We investigate the effects of the nearby interstellar medium (ISM) on the locally measured cosmic-ray (CR) spectra. Using the G al P rop code, we explore how variations in the local gas and source distributions affect spectral features at low energies. Comparing with recent Voyager 1 measurements taken in the local ISM, we show that for a realistic interstellar gas distribution the data favor models in which there are no significant CR sources within ∼150–200 pc of the solar system, implying that the nearest dominant contributors to the low-energy CR flux are located at distances beyond this range. We find that the modeling supports the conclusion of A. C. Cummings et al. that there is a significant fraction of primary boron in its observed spectrum at low energies. Our study shows that detailed modeling of the immediate Galactic environment is required to robustly infer Galactic CR propagation parameters from local measurements and that accounting for nearby ISM structure can alleviate tensions between direct CR data and global propagation models.
",
"doi": "10.3847/1538-4357/ae4c57",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2026-04-10",
"series_number": "1",
"volume": "1001",
"issue": "1",
"pages": "17"
},
{
"id": "authors:ycxkr-2tn85",
"collection": "authors",
"collection_id": "ycxkr-2tn85",
"cite_using_url": "https://authors.library.caltech.edu/records/ycxkr-2tn85",
"type": "article",
"title": "Voyager 1 Observations of Galactic Cosmic-Ray Isotopes in the Very Local Interstellar Medium: Evidence for Primary \u00b2H and B",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Moskalenko",
"given_name": "I. V.",
"orcid": "0000-0001-6141-458X"
},
{
"family_name": "Heikkila",
"given_name": "B. C."
},
{
"family_name": "J\u00f3hannesson",
"given_name": "G.",
"orcid": "0000-0003-1458-7036"
},
{
"family_name": "Porter",
"given_name": "T. A.",
"orcid": "0000-0002-2621-4440"
}
],
"abstract": "\n
We present the first measurements of the energy spectra of the isotopes of Galactic cosmic rays (GCRs) with nuclear charge Z = 1–14 in the very local interstellar medium (VLISM). We also update our previously published energy spectra of GCR elements in the VLISM from Z = 1–28 for a new longer time period of observations, 2013 January 1 through 2021 December 31. The observations are from the Cosmic Ray Subsystem on the Voyager 1 (V1) spacecraft and cover the Z-dependent energy range from ∼3 to 661 MeV nuc−1. The data are fit to eight models using the GCR propagation code GalProp, which differ by having four options for fragmentation and two options for production cross sections. The models are all plain diffusion models with injection spectra as power laws in rigidity, where the propagation parameters and the injection power-law index are the same for all species, and derived self-consistently and independently for each model. The VLISM energy spectra generated by the models agree reasonably well with the observed VLISM energy spectra for the elements with Z = 1–28 and with the isotopes with Z = 1–14. However, to achieve reasonable fits to the 2H and B energy spectra, it was necessary to add a primary source of 2H and B.
\n
\n
In the latter moments of 2023 July 17, the solar active region (AR) 13363, near the southwestern face of the Sun, was undergoing considerable evolution, which resulted in a significant solar energetic particle (SEP) event measured by Parker Solar Probe’s Integrated Science Investigation of the Sun (IS\u2299IS) and near-Earth spacecraft. Remote observations from GOES and CHASE captured two M5.0+ solar flares that peaked at 23:34 and 00:06 UT from the source region. In tandem, STEREO COR2 first recorded a small, narrow coronal mass ejection (CME) emerging at 22:54 UT and then saw a major halo CME emerge at 23:43 UT with a bright, rapidly expanding core and CME-driven magnetic shock with an estimated speed of ∼1400 km s−1. Parker Solar Probe was positioned at 0.65 au, near-perfectly on the nominal Parker spiral magnetic field line, which connected Earth and the AR for a 537 km s−1 ambient solar wind speed at L1. This fortuitous alignment provided the opportunity to examine how the SEP velocity dispersion, energy spectra, elemental composition, and fluence varied from 0.65 to 1 au along a shared magnetic connection to the Sun. We find a strong radial gradient, which is best characterized for H and He as r−4.0, and most surprisingly, is stronger for O and Fe, which is better described by r−5.7.
\n
\n
The 2021 October 28 solar energetic particle (SEP) event was a rare ground level enhancement (GLE) event, where secondary particles from the interactions of SEPs with the Earth's atmosphere were detected by neutron monitors on the ground. A number of papers have examined the solar signatures, neutron monitor observations, and the characteristics of the SEP protons and electrons for this event. Here we describe the heavy ion signatures, specifically O and Fe, observed by multiple spacecraft. Parker Solar Probe, Solar Terrestrial Relations Observatory-Ahead, and Advanced Composition Explorer were distributed over nearly 60° in solar longitude and 0.4 au in heliocentric distance. Despite their separations, all three spacecraft measured event-integrated O and Fe spectra, well represented by power laws, with nearly the same power-law index of approximately −1.7, which is significantly harder than most large SEP events and many GLE events. Moreover, the Fe/O abundance ratio determined from these spectra was also found to be spatially invariant over the 60° in longitude and 0.4 au in heliocentric distance. Such near uniformity is highly unusual, and only one similar occurrence was found in a previous multispacecraft. The observed Fe/O ratio of 0.39 is higher than typical for large SEP events but not unusual for GLE events.
\n
Edward Stone was a pre-eminent space scientist with an exceptional record of leading space missions and building ground-based astronomical facilities. The public face of NASA’s Voyager missions for the launch of the two probes in 1977, he served as project scientist for 50 years. Stone introduced the world to the wonders of the gas-giant planets (Jupiter, Saturn, Uranus and Neptune) in multiple press conferences, from Voyager 1’s encounter with Jupiter in 1979 to Voyager 2’s fly-by of Neptune in 1989. He also oversaw the probes entering interstellar space — the first in 2012 and the second in 2018. They continue to transmit data to Earth today.
",
"doi": "10.1038/d41586-024-02285-w",
"issn": "0028-0836",
"publisher": "Nature Publishing Group",
"publication": "Nature",
"publication_date": "2024-07-18",
"series_number": "8021",
"volume": "631",
"issue": "8021",
"pages": "501"
},
{
"id": "authors:e15ew-kkm87",
"collection": "authors",
"collection_id": "e15ew-kkm87",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20220908-184327219",
"type": "article",
"title": "The Isotopic Abundances of Galactic Cosmic Rays with Atomic Number 29 \u2264 Z \u2264 38",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-Mark-E"
},
{
"family_name": "Rosenvinge",
"given_name": "T. T. von",
"orcid": "0000-0001-7320-4141",
"clpid": "Rosenvinge-T-T-von"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Nolfo",
"given_name": "G. A. de",
"orcid": "0000-0002-3677-074X",
"clpid": "Nolfo-G-A-de"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The Cosmic Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer spacecraft has been operating successfully in a halo orbit about the L1 Lagrange point since late 1997. We report here the isotopic composition of the Galactic cosmic ray (GCR) elements with 29 \u2264 Z \u2264 38 derived from more than 20 years of CRIS data. Using a model of cosmic-ray transport in the Galaxy and the solar system (SS), we have derived from these observations the isotopic composition of the accelerated material at the GCR source (GCRS). Comparison of the isotopic fractions of these elements in the GCRS with corresponding fractions in the solar system gives no indication of GCRS enrichment in r-process isotopes. Since a large fraction of core-collapse supernovae (CCSNe) occur in OB associations, the fact that GCRs do not contain enhanced abundances of r-process nuclides indicates that CCSNe are not the principal source of lighter (Z \u2264 38) r-process nuclides in the solar system. This conclusion supports recent work that points to binary neutron-star mergers, rather than supernovae, as the principal source of galactic r-process isotopes.",
"doi": "10.3847/1538-4357/ac82e7",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2022-09-01",
"series_number": "1",
"volume": "936",
"issue": "1",
"pages": "13"
},
{
"id": "authors:rj39w-zab87",
"collection": "authors",
"collection_id": "rj39w-zab87",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20210608-140607023",
"type": "article",
"title": "Magnetic field line random walk and solar energetic particle path lengths. Stochastic theory and PSP/IS\u2299IS observations",
"author": [
{
"family_name": "Chhiber",
"given_name": "R.",
"clpid": "Chhiber-R"
},
{
"family_name": "Matthaeus",
"given_name": "W. H."
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Ruffolo",
"given_name": "D."
},
{
"family_name": "Sonsrettee",
"given_name": "W."
},
{
"family_name": "Tooprakai",
"given_name": "P."
},
{
"family_name": "Seripienlert",
"given_name": "A."
},
{
"family_name": "Chuychai",
"given_name": "P."
},
{
"family_name": "Usmanov",
"given_name": "A. V."
},
{
"family_name": "Goldstein",
"given_name": "M. L."
},
{
"family_name": "McComas",
"given_name": "D. J."
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Szalay",
"given_name": "J. R."
},
{
"family_name": "Joyce",
"given_name": "C. J."
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Roelof",
"given_name": "E. C.",
"orcid": "0000-0002-2270-0652"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-Allan-W"
},
{
"family_name": "Giacalone",
"given_name": "J.",
"orcid": "0000-0002-0850-4233"
},
{
"family_name": "Schwadron",
"given_name": "N. A.",
"orcid": "0000-0002-3737-9283"
},
{
"family_name": "Mitchell",
"given_name": "D. G.",
"orcid": "0000-0003-1960-2119"
},
{
"family_name": "Hill",
"given_name": "M. E.",
"orcid": "0000-0002-5674-4936"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-Mark-E"
},
{
"family_name": "McNutt",
"given_name": "R. L.",
"orcid": "0000-0002-4722-9166"
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008"
}
],
"abstract": "Context. In 2020 May-June, six solar energetic ion events were observed by the Parker Solar Probe/IS\u2299IS instrument suite at \u22480.35 AU from the Sun. From standard velocity-dispersion analysis, the apparent ion path length is \u22480.625 AU at the onset of each event. \n\nAims. We develop a formalism for estimating the path length of random-walking magnetic field lines to explain why the apparent ion path length at an event onset greatly exceeds the radial distance from the Sun for these events. \n\nMethods. We developed analytical estimates of the average increase in path length of random-walking magnetic field lines, relative to the unperturbed mean field. Monte Carlo simulations of field line and particle trajectories in a model of solar wind turbulence were used to validate the formalism and study the path lengths of particle guiding-center and full-orbital trajectories. The formalism was implemented in a global solar wind model, and the results are compared with ion path lengths inferred from IS\u2299IS observations. \n\nResults. Both a simple estimate and a rigorous theoretical formulation are obtained for field-lines' path length increase as a function of path length along the large-scale field. From simulated field line and particle trajectories, we find that particle guiding centers can have path lengths somewhat shorter than the average field line path length, while particle orbits can have substantially longer path lengths due to their gyromotion with a nonzero effective pitch angle. \n\nConclusions. The long apparent path length during these solar energetic ion events can be explained by (1) a magnetic field line path length increase due to the field line random walk and (2) particle transport about the guiding center with a nonzero effective pitch angle due to pitch angle scattering. Our formalism for computing the magnetic field line path length, accounting for turbulent fluctuations, may be useful for application to solar particle transport in general.",
"doi": "10.1051/0004-6361/202039816",
"issn": "0004-6361",
"publisher": "EDP Sciences",
"publication": "Astronomy and Astrophysics",
"publication_date": "2021-06",
"volume": "650",
"pages": "Art. No. \tA26"
},
{
"id": "authors:p0mr3-esh29",
"collection": "authors",
"collection_id": "p0mr3-esh29",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20201002-094021793",
"type": "article",
"title": "Voyager 2 Observations Near the Heliopause",
"author": [
{
"family_name": "Richardson",
"given_name": "John D.",
"orcid": "0000-0003-4041-7540",
"clpid": "Richardson-J-D"
},
{
"family_name": "Belcher",
"given_name": "John W.",
"clpid": "Belcher-J-W"
},
{
"family_name": "Burlaga",
"given_name": "Leonard F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
},
{
"family_name": "Cummings",
"given_name": "Alan C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Decker",
"given_name": "Robert B.",
"clpid": "Decker-R-B"
},
{
"family_name": "Opher",
"given_name": "Merav",
"clpid": "Opher-M"
},
{
"family_name": "Stone",
"given_name": "Edward C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "This paper discusses plasma characteristics in the heliosheath region before the heliopause (HP), at the HP, and in the very local interstellar medium (VLISM). The Voyager 2 (V2) HP was a sharp boundary where the radial plasma currents went to background levels. The radial flow speeds derived from 53-85 keV (V1) and 28-43 keV (V2) ion data decreased about 2 years (8 AU) before the HP at V1 and V2. A speed decrease was not observed by the V2 plasma instrument until 160 days (1.5 AU) before the HP crossing when V2 entered the plasma boundary layer where the plasma density and 28-43 keV ion intensity increased. We determine the HP orientation based on the plasma flow and magnetic field data and show these observations are consistent with models predicting a blunt HP. Variations are observed in the currents observed in the VLISM; roll data from this region clearly show the plasma instrument observes the interstellar plasma and may be consistent with larger than expected VLISM temperatures near the HP.",
"doi": "10.1088/1742-6596/1620/1/012016",
"issn": "1742-6588",
"publisher": "IOP",
"publication": "Journal of Physics Conference Series",
"publication_date": "2020-09-30",
"volume": "1620",
"pages": "Art. No. 012016"
},
{
"id": "authors:thaks-ave64",
"collection": "authors",
"collection_id": "thaks-ave64",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200203-092721301",
"type": "article",
"title": "Seed Population Preconditioning and Acceleration Observed by the Parker Solar Probe",
"author": [
{
"family_name": "Schwadron",
"given_name": "N. A.",
"orcid": "0000-0002-3737-9283",
"clpid": "Schwadron-N-A"
},
{
"family_name": "Bale",
"given_name": "S.",
"orcid": "0000-0002-1989-3596"
},
{
"family_name": "Bonnell",
"given_name": "J."
},
{
"family_name": "Case",
"given_name": "A.",
"orcid": "0000-0002-3520-4041"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Dudok de Wit",
"given_name": "T.",
"orcid": "0000-0002-4401-0943"
},
{
"family_name": "de Wet",
"given_name": "W."
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008"
},
{
"family_name": "Joyce",
"given_name": "C. J.",
"orcid": "0000-0002-3841-5020"
},
{
"family_name": "Goetz",
"given_name": "K."
},
{
"family_name": "Giacalone",
"given_name": "J."
},
{
"family_name": "Goerby",
"given_name": "M."
},
{
"family_name": "Harvey",
"given_name": "P."
},
{
"family_name": "Heber",
"given_name": "B.",
"orcid": "0000-0003-0960-5658"
},
{
"family_name": "Hill",
"given_name": "M. E.",
"orcid": "0000-0002-5674-4936"
},
{
"family_name": "Karavolos",
"given_name": "M."
},
{
"family_name": "Kasper",
"given_name": "J. C.",
"orcid": "0000-0002-7077-930X"
},
{
"family_name": "Korreck",
"given_name": "K.",
"orcid": "0000-0001-6095-2490"
},
{
"family_name": "Larson",
"given_name": "D."
},
{
"family_name": "Livi",
"given_name": "R."
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Malandraki",
"given_name": "O."
},
{
"family_name": "MacDowall",
"given_name": "R.",
"orcid": "0000-0003-3112-4201"
},
{
"family_name": "Malaspina",
"given_name": "D.",
"orcid": "0000-0003-1191-1558"
},
{
"family_name": "Matthaeus",
"given_name": "W. H.",
"orcid": "0000-0001-7224-6024"
},
{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158"
},
{
"family_name": "McNutt",
"given_name": "R. L., Jr."
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Mitchell",
"given_name": "D. G.",
"orcid": "0000-0003-1960-2119"
},
{
"family_name": "Mays",
"given_name": "L."
},
{
"family_name": "Niehof",
"given_name": "J. T."
},
{
"family_name": "Odstrcil",
"given_name": "D."
},
{
"family_name": "Pulupa",
"given_name": "M.",
"orcid": "0000-0002-1573-7457"
},
{
"family_name": "Poduval",
"given_name": "B."
},
{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444"
},
{
"family_name": "Roelof",
"given_name": "E. C."
},
{
"family_name": "Stevens",
"given_name": "M.",
"orcid": "0000-0002-7728-0085"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Szalay",
"given_name": "J. R.",
"orcid": "0000-0003-2685-9801"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Winslow",
"given_name": "R."
},
{
"family_name": "Whittlesey",
"given_name": "P."
}
],
"abstract": "A series of solar energetic particle (SEP) events was observed by the Integrated Science Investigation of the Sun (IS\u2299IS) on the Parker Solar Probe (PSP) during the period from 2019 April 18 through 24. The PSP spacecraft was located near 0.48 au from the Sun on Parker spiral field lines that projected out to 1 au within ~25\u00b0 of the near-Earth spacecraft. These SEP events, though small compared to historically large SEP events, were among the largest observed thus far in the PSP mission and provide critical information about the space environment inside 1 au during SEP events. During this period, the Sun released multiple coronal mass ejections (CMEs). One of these CMEs observed was initiated on 2019 April 20 at 01:25 UTC, and the interplanetary CME (ICME) propagated out and passed over the PSP spacecraft. Observations by the Electromagnetic Fields Investigation show that the magnetic field structure was mostly radial throughout the passage of the compression region and the plasma that followed, indicating that PSP did not directly observe a flux rope internal to the ICME, consistent with the location of PSP on the ICME flank. Analysis using relativistic electrons observed near Earth by the Electron, Proton and Alpha Monitor on the Advanced Composition Explorer demonstrates the presence of electron seed populations (40\u2013300 keV) during the events observed. The energy spectrum of the IS\u2299IS-observed proton seed population below 1 MeV is close to the limit of possible stationary-state plasma distributions out of equilibrium. IS\u2299IS observations reveal the enhancement of seed populations during the passage of the ICME, which likely indicates a key part of the preacceleration process that occurs close to the Sun.",
"doi": "10.3847/1538-4365/ab5527",
"issn": "1538-4365",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Supplement Series",
"publication_date": "2020-02",
"series_number": "2",
"volume": "246",
"issue": "2",
"pages": "Art. No. 33"
},
{
"id": "authors:87qdd-8eb27",
"collection": "authors",
"collection_id": "87qdd-8eb27",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200203-104219201",
"type": "article",
"title": "Energetic Particle Increases Associated with Stream Interaction Regions",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
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{
"family_name": "Davis",
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{
"family_name": "Desai",
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{
"family_name": "Giacalone",
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{
"family_name": "Hill",
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{
"family_name": "Joyce",
"given_name": "C. J.",
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{
"family_name": "Labrador",
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{
"family_name": "Leske",
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{
"family_name": "Matthaeus",
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{
"family_name": "McComas",
"given_name": "D. J.",
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},
{
"family_name": "McNutt",
"given_name": "R. L., Jr."
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
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{
"family_name": "Mitchell",
"given_name": "D. G.",
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{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444"
},
{
"family_name": "Roelof",
"given_name": "E. C."
},
{
"family_name": "Schwadron",
"given_name": "N. A.",
"orcid": "0000-0002-3737-9283"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Szalay",
"given_name": "J. R.",
"orcid": "0000-0003-2685-9801"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128"
},
{
"family_name": "Allen",
"given_name": "R. C.",
"orcid": "0000-0003-2079-5683"
},
{
"family_name": "Ho",
"given_name": "G. C."
},
{
"family_name": "Jian",
"given_name": "L. K.",
"orcid": "0000-0002-6849-5527"
},
{
"family_name": "Lario",
"given_name": "D.",
"orcid": "0000-0002-3176-8704"
},
{
"family_name": "Odstrcil",
"given_name": "D."
},
{
"family_name": "Bale",
"given_name": "S. D.",
"orcid": "0000-0002-1989-3596"
},
{
"family_name": "Badman",
"given_name": "S. T.",
"orcid": "0000-0002-6145-436X"
},
{
"family_name": "Pulupa",
"given_name": "M.",
"orcid": "0000-0002-1573-7457"
},
{
"family_name": "MacDowall",
"given_name": "R. J.",
"orcid": "0000-0003-3112-4201"
},
{
"family_name": "Kasper",
"given_name": "J. C.",
"orcid": "0000-0002-7077-930X"
},
{
"family_name": "Case",
"given_name": "A. W.",
"orcid": "0000-0002-3520-4041"
},
{
"family_name": "Korreck",
"given_name": "K. E.",
"orcid": "0000-0001-6095-2490"
},
{
"family_name": "Larson",
"given_name": "D. E."
},
{
"family_name": "Livi",
"given_name": "Roberto"
},
{
"family_name": "Stevens",
"given_name": "M. L.",
"orcid": "0000-0002-7728-0085"
},
{
"family_name": "Whittlesey",
"given_name": "Phyllis"
}
],
"abstract": "The Parker Solar Probe was launched on 2018 August 12 and completed its second orbit on 2019 June 19 with perihelion of 35.7 solar radii. During this time, the Energetic Particle Instrument-Hi (EPI-Hi, one of the two energetic particle instruments comprising the Integrated Science Investigation of the Sun, IS\u2299IS) measured seven proton intensity increases associated with stream interaction regions (SIRs), two of which appear to be occurring in the same region corotating with the Sun. The events are relatively weak, with observed proton spectra extending to only a few MeV and lasting for a few days. The proton spectra are best characterized by power laws with indices ranging from \u22124.3 to \u22126.5, generally softer than events associated with SIRs observed at 1 au and beyond. Helium spectra were also obtained with similar indices, allowing He/H abundance ratios to be calculated for each event. We find values of 0.016\u20130.031, which are consistent with ratios obtained previously for corotating interaction region events with fast solar wind \u2264 600 km s\u207b\u00b9. Using the observed solar wind data combined with solar wind simulations, we study the solar wind structures associated with these events and identify additional spacecraft near 1 au appropriately positioned to observe the same structures after some corotation. Examination of the energetic particle observations from these spacecraft yields two events that may correspond to the energetic particle increases seen by EPI-Hi earlier.",
"doi": "10.3847/1538-4365/ab4c38",
"issn": "1538-4365",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Supplement Series",
"publication_date": "2020-02",
"series_number": "2",
"volume": "246",
"issue": "2",
"pages": "Art. No. 20"
},
{
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"collection_id": "vr2bs-atw39",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200203-131825142",
"type": "article",
"title": "Observations of the 2019 April 4 Solar Energetic Particle Event at the Parker Solar Probe",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
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{
"family_name": "Christian",
"given_name": "E. R.",
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{
"family_name": "Cohen",
"given_name": "C. M. S.",
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{
"family_name": "Cummings",
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{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
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{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008"
},
{
"family_name": "Giacalone",
"given_name": "J."
},
{
"family_name": "Hill",
"given_name": "M. E.",
"orcid": "0000-0002-5674-4936"
},
{
"family_name": "Joyce",
"given_name": "C. J.",
"orcid": "0000-0002-3841-5020"
},
{
"family_name": "Krimigis",
"given_name": "S. M.",
"orcid": "0000-0003-2781-2386"
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{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
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{
"family_name": "Malandraki",
"given_name": "O.",
"orcid": "0000-0002-4751-6835"
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{
"family_name": "Matthaeus",
"given_name": "W. H.",
"orcid": "0000-0001-7224-6024"
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{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158"
},
{
"family_name": "McNutt",
"given_name": "R. L., Jr."
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
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{
"family_name": "Mitchell",
"given_name": "D. G.",
"orcid": "0000-0003-1960-2119"
},
{
"family_name": "Posner",
"given_name": "A.",
"orcid": "0000-0003-1572-8734"
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{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444"
},
{
"family_name": "Roelof",
"given_name": "E. C."
},
{
"family_name": "Schwadron",
"given_name": "N. A.",
"orcid": "0000-0002-3737-9283"
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{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
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{
"family_name": "Szalay",
"given_name": "J. R.",
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{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128"
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{
"family_name": "Vourlidas",
"given_name": "A.",
"orcid": "0000-0002-8164-5948"
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{
"family_name": "Bale",
"given_name": "S. D.",
"orcid": "0000-0002-1989-3596"
},
{
"family_name": "MacDowall",
"given_name": "R. J.",
"orcid": "0000-0003-3112-4201"
},
{
"family_name": "Pulupa",
"given_name": "M.",
"orcid": "0000-0002-1573-7457"
},
{
"family_name": "Kasper",
"given_name": "J. C.",
"orcid": "0000-0002-7077-930X"
},
{
"family_name": "Allen",
"given_name": "R. C.",
"orcid": "0000-0003-2079-5683"
},
{
"family_name": "Case",
"given_name": "A. W.",
"orcid": "0000-0002-3520-4041"
},
{
"family_name": "Korreck",
"given_name": "K. E.",
"orcid": "0000-0001-6095-2490"
},
{
"family_name": "Livi",
"given_name": "R.",
"orcid": "0000-0002-0396-0547"
},
{
"family_name": "Stevens",
"given_name": "M. L.",
"orcid": "0000-0002-7728-0085"
},
{
"family_name": "Whittlesey",
"given_name": "P.",
"orcid": "0000-0002-7287-5098"
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{
"family_name": "Poduval",
"given_name": "B.",
"orcid": "0000-0003-1258-0308"
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],
"abstract": "A solar energetic particle event was detected by the Integrated Science Investigation of the Sun (IS\u2299IS) instrument suite on Parker Solar Probe (PSP) on 2019 April 4 when the spacecraft was inside of 0.17 au and less than 1 day before its second perihelion, providing an opportunity to study solar particle acceleration and transport unprecedentedly close to the source. The event was very small, with peak 1 MeV proton intensities of ~0.3 particles (cm\u00b2 sr s MeV)\u207b\u00b9, and was undetectable above background levels at energies above 10 MeV or in particle detectors at 1 au. It was strongly anisotropic, with intensities flowing outward from the Sun up to 30 times greater than those flowing inward persisting throughout the event. Temporal association between particle increases and small brightness surges in the extreme-ultraviolet observed by the Solar TErrestrial RElations Observatory, which were also accompanied by type III radio emission seen by the Electromagnetic Fields Investigation on PSP, indicates that the source of this event was an active region nearly 80\u00b0 east of the nominal PSP magnetic footpoint. This suggests that the field lines expanded over a wide longitudinal range between the active region in the photosphere and the corona.",
"doi": "10.3847/1538-4365/ab5712",
"issn": "1538-4365",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Supplement Series",
"publication_date": "2020-02",
"series_number": "2",
"volume": "246",
"issue": "2",
"pages": "Art. No. 35"
},
{
"id": "authors:sbf8x-a1b82",
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"collection_id": "sbf8x-a1b82",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200203-092721818",
"type": "article",
"title": "\u00b3He-rich Solar Energetic Particle Observations at the Parker Solar Probe and near Earth",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
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{
"family_name": "Bu\u010dik",
"given_name": "R.",
"orcid": "0000-0001-7381-6949"
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{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618"
},
{
"family_name": "Ho",
"given_name": "G. C.",
"orcid": "0000-0003-1093-2066"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
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{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
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{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937"
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{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
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{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008"
},
{
"family_name": "Giacalone",
"given_name": "J."
},
{
"family_name": "Haggerty",
"given_name": "D. K.",
"orcid": "0000-0001-6395-8943"
},
{
"family_name": "Hill",
"given_name": "M. E.",
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{
"family_name": "Joyce",
"given_name": "C. J.",
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{
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"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
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{
"family_name": "Malandraki",
"given_name": "O.",
"orcid": "0000-0002-4751-6835"
},
{
"family_name": "Matthaeus",
"given_name": "W. H.",
"orcid": "0000-0001-7224-6024"
},
{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158"
},
{
"family_name": "McNutt",
"given_name": "R. L., Jr.",
"orcid": "0000-0002-4722-9166"
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{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
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{
"family_name": "Mitchell",
"given_name": "D. G.",
"orcid": "0000-0003-1960-2119"
},
{
"family_name": "Posner",
"given_name": "A.",
"orcid": "0000-0003-1572-8734"
},
{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444"
},
{
"family_name": "Roelof",
"given_name": "E. C.",
"orcid": "0000-0002-2270-0652"
},
{
"family_name": "Schwadron",
"given_name": "N. A.",
"orcid": "0000-0002-3737-9283"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Szalay",
"given_name": "J. R.",
"orcid": "0000-0003-2685-9801"
},
{
"family_name": "Bale",
"given_name": "S. D.",
"orcid": "0000-0002-1989-3596"
},
{
"family_name": "Case",
"given_name": "A. W.",
"orcid": "0000-0002-3520-4041"
},
{
"family_name": "Kasper",
"given_name": "J. C.",
"orcid": "0000-0002-7077-930X"
},
{
"family_name": "Korreck",
"given_name": "K. E.",
"orcid": "0000-0001-6095-2490"
},
{
"family_name": "Larson",
"given_name": "D. E.",
"orcid": "0000-0001-5030-6030"
},
{
"family_name": "MacDowall",
"given_name": "R. J.",
"orcid": "0000-0003-3112-4201"
},
{
"family_name": "Pulupa",
"given_name": "M.",
"orcid": "0000-0002-1573-7457"
},
{
"family_name": "Stevens",
"given_name": "M. L.",
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],
"abstract": "The Integrated Science Investigation of the Sun (IS\u2299IS) instrument suite on the Parker Solar Probe (PSP) spacecraft is making in situ observations of energetic ions and electrons closer to the Sun than any previous mission. Using data collected during its first two orbits, which reached perihelion distances of 0.17 au, we have searched for \u00b3He-rich solar energetic particle (SEP) events under very quiet solar minimum conditions. On 2019-110\u2013111 (April 20\u201321), \u00b3He-rich SEPs were observed at energies near 1 MeV nucleon \u207b\u00b9 in association with energetic protons, heavy ions, and electrons. This activity was also detected by the Ultra-Low-Energy Isotope Spectrometer and the Electron, Proton, and Alpha Monitor instruments on the Advanced Composition Explorer (ACE) spacecraft located near Earth, 0.99 au from the Sun. At that time, PSP and ACE were both magnetically connected to locations near the west limb of the Sun. Remote sensing measurements showed the presence of type III radio bursts and also helical jets from this region of the Sun. This combination of observations is commonly associated with \u00b3He-rich SEP acceleration on the Sun. AR 12738, which was located at Carrington coordinates from which numerous X-ray flares were observed over a period of more than 6 months, was identified as the source of the \u00b3He-rich events. This region was also the source of several other SEP events detected at PSP or ACE. Aside from the period in 2019 April, IS\u2299IS did not observe any other \u00b3He-rich SEPs during orbits 1 and 2.",
"doi": "10.3847/1538-4365/ab5963",
"issn": "1538-4365",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Supplement Series",
"publication_date": "2020-02",
"series_number": "2",
"volume": "246",
"issue": "2",
"pages": "Art. No. 42"
},
{
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"collection_id": "1bfnf-pry08",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200203-092721619",
"type": "article",
"title": "Energetic Particle Observations from the Parker Solar Probe Using Combined Energy Spectra from the IS\u2299IS Instrument Suite",
"author": [
{
"family_name": "Joyce",
"given_name": "C. J.",
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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{
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"given_name": "J. S.",
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{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008",
"clpid": "Desai-M-I"
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{
"family_name": "Giacalone",
"given_name": "J.",
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{
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}
],
"abstract": "The Integrated Science Investigations of the Sun (IS\u2299IS) instrument suite includes two Energetic Particle instruments: EPI-Hi, designed to measure ions from ~1 to 200 MeV nuc\u207b\u00b9, and EPI-Lo, designed to measure ions from ~20 to ~15 MeV nuc\u207b\u00b9. We present an analysis of eight energetic proton events observed across the energy range of both instruments during Parker Solar Probe's (PSP) first two orbits in order to examine their combined energy spectra. Background corrections are applied to help resolve spectral breaks between the two instruments and are shown to be effective. In doing so we demonstrate that even in the early stages of calibration, IS\u2299IS is capable of producing reliable spectral observations across broad energy ranges. In addition to making groundbreaking measurements very near the Sun, IS\u2299IS also characterizes energetic particle populations over a range of heliocentric distances inside 1 au. During the first two orbits, IS\u2299IS observed energetic particle events from a single corotating interaction region (CIR) at three different distances from the Sun. The events are separated by two Carrington rotations and just 0.11 au in distance; however, the relationship shown between proton intensities and proximity of the spacecraft to the source region shows evidence of the importance of transport effects on observations of energetic particles from CIRs. Future IS\u2299IS observations of similar events over larger distances will help disentangle the effects of CIR-related acceleration and transport. We apply similar spectral analyses to the remaining five events, including four that are likely related to stream interaction regions (SIRs) and one solar energetic particle (SEP) event.",
"doi": "10.3847/1538-4365/ab5948",
"issn": "1538-4365",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Supplement Series",
"publication_date": "2020-02",
"series_number": "2",
"volume": "246",
"issue": "2",
"pages": "Art. No. 41"
},
{
"id": "authors:s0bt8-xes74",
"collection": "authors",
"collection_id": "s0bt8-xes74",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20191202-155700225",
"type": "article",
"title": "ACR Proton Acceleration Associated with Reconnection Processes beyond the Heliospheric Termination Shock",
"author": [
{
"family_name": "Zhao",
"given_name": "L.-L.",
"orcid": "0000-0002-4299-0490",
"clpid": "Zhao-Lingling"
},
{
"family_name": "Zank",
"given_name": "G. P.",
"orcid": "0000-0002-4642-6192",
"clpid": "Zank-G-P"
},
{
"family_name": "Hu",
"given_name": "Q.",
"orcid": "0000-0002-7570-2301",
"clpid": "Hu-Qiang"
},
{
"family_name": "Chen",
"given_name": "Y.",
"orcid": "0000-0002-0065-7622",
"clpid": "Chen-Yu"
},
{
"family_name": "Adhikari",
"given_name": "L.",
"orcid": "0000-0003-1549-5256",
"clpid": "Adhikari-L"
},
{
"family_name": "leRoux",
"given_name": "J. A.",
"orcid": "0000-0001-9199-2890",
"clpid": "leRoux-J-A"
},
{
"family_name": "Cummings",
"given_name": "A.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Burlaga",
"given_name": "L. F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
}
],
"abstract": "One of the curious observations from the Voyagers is that the intensity of anomalous cosmic rays (ACRs) did not peak at the heliospheric termination shock (HTS) but instead a short distance (within ~1 au) downstream of the HTS. One possible explanation is that the interaction of the wavy heliospheric current sheet with the HTS enhances magnetic reconnection and generates numerous small-scale magnetic flux ropes in the heliosheath immediately downstream of the HTS. Charged particles are accelerated in this region due to Fermi acceleration and the reconnection electric field. In this work, we provide observational evidence of the presence of magnetic flux ropes in the heliosheath region just downstream of the HTS using a wavelet analysis of the reduced magnetic helicity and Grad\u2013Shafranov reconstruction techniques. The Zank et al. kinetic transport theory for particles propagating through the magnetic islands region is employed to fit the observed energetic proton intensities in the post-HTS region. Our modeling results agree reasonably well with the observations, which suggests that stochastic acceleration via reconnection processes can explain the ACR proton peak beyond the HTS.",
"doi": "10.3847/1538-4357/ab4db4",
"issn": "1538-4357",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2019-12-01",
"series_number": "2",
"volume": "886",
"issue": "2",
"pages": "Art. No. 144"
},
{
"id": "authors:85fpw-hjk26",
"collection": "authors",
"collection_id": "85fpw-hjk26",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190926-164717298",
"type": "article",
"title": "Cosmic ray measurements from Voyager 2 as it crossed into interstellar space",
"author": [
{
"family_name": "Stone",
"given_name": "Edward C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "Alan C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Heikkila",
"given_name": "Bryant C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "Nand",
"clpid": "Lal-Nand"
}
],
"abstract": "The interaction of the interstellar and solar winds is complex, as revealed by differences in intensities and anisotropies of low-energy ions (>0.5\u2009MeV per nucleon) originating inside the heliosphere and those of higher-energy Galactic cosmic rays (>70\u2009MeV per nucleon) originating outside, in the Milky Way. On 5 November 2018, Voyager 2 observed a sharp decrease in the intensity of low-energy ions and a simultaneous increase in the intensity of cosmic rays, indicating that Voyager 2 had crossed the heliopause at 119\u2009au and entered interstellar space about six years after Voyager 1. Unlike Voyager 1, which found that two interstellar flux tubes had invaded the heliosheath and served as precursors to the heliopause, Voyager 2 found no similar precursors. However, just beyond the heliopause Voyager 2 discovered a boundary layer, in which low-energy particles streamed outward along the magnetic field and cosmic ray intensities were only 90% of those further out.",
"doi": "10.1038/s41550-019-0928-3",
"issn": "2397-3366",
"publisher": "Nature Publishing Group",
"publication": "Nature Astronomy",
"publication_date": "2019-11",
"series_number": "11",
"volume": "3",
"issue": "11",
"pages": "1013-1018"
},
{
"id": "authors:4bqp6-1fh76",
"collection": "authors",
"collection_id": "4bqp6-1fh76",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20190321-114830889",
"type": "article",
"title": "Galactic Cosmic-Ray Anisotropies: Voyager 1 in the Local Interstellar Medium",
"author": [
{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444",
"clpid": "Rankin-J-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158",
"clpid": "McComas-D-J"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-Nand"
},
{
"family_name": "Heikkila",
"given_name": "B. C.",
"clpid": "Heikkila-B-C"
}
],
"abstract": "Since crossing the heliopause on 2012 August 25, Voyager 1 observed reductions in galactic cosmic ray count rates caused by a time-varying depletion of particles with pitch angles near 90\u00b0, while intensities of particles with other pitch angles remain unchanged. Between late 2012 and mid-2017, three large-scale events occurred, lasting from ~100 to ~630 days. Omnidirectional and directional high-energy data from Voyager 1's Cosmic Ray Subsystem are used to report cosmic ray intensity variations. Omnidirectional (\u227320 MeV) proton-dominated measurements show up to a 3.8% intensity reduction. Bidirectional (\u227370 MeV) proton-dominated measurements taken from various spacecraft orientations provide insight about the depletion region's spatial properties. We characterize the anisotropy as a \"notch\" in an otherwise uniform pitch angle distribution of varying depth and width centered about 90\u00b0 in pitch angle space. The notch averages 22\u00b0 wide and 15% deep, signifying a depletion region that is broad and shallow. There are indications that the anisotropy is formed by a combination of magnetic trapping and cooling downstream of solar-induced transient disturbances in a region that is also likely influenced by the highly compressed fields near the heliopause.",
"doi": "10.3847/1538-4357/ab041f",
"issn": "1538-4357",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2019-03-01",
"series_number": "1",
"volume": "873",
"issue": "1",
"pages": "Art. No. 46"
},
{
"id": "authors:5x61c-yn009",
"collection": "authors",
"collection_id": "5x61c-yn009",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20181025-112020309",
"type": "article",
"title": "Voyager 2 Observations of Plasma and Pressure Pulses",
"author": [
{
"family_name": "Richardson",
"given_name": "John D.",
"orcid": "0000-0003-4041-7540",
"clpid": "Richardson-J-D"
},
{
"family_name": "Belcher",
"given_name": "John W.",
"clpid": "Belcher-J-W"
},
{
"family_name": "Cummings",
"given_name": "Alan C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Decker",
"given_name": "Robert",
"clpid": "Decker-R"
},
{
"family_name": "Stone",
"given_name": "Edward C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "This paper provides the latest data from Voyager 2 on plasma characteristics in the heliosheath including the observations of pressure waves in the plasma and particle data. Models and observations show that solar transients drive pressure waves through the heliosphere. Pressure pulses that could drive heliosheath waves are observed near the previous solar maximum upstream of the termination shock. We show that the most recent data is consistent with the presence of pressure waves and compare the heliosheath waves with the pressure increases in the heliosheath. The magnetic field is better correlated with density and galactic cosmic ray intensities in the supersonic solar wind than in the heliosheath. The galactic cosmic rays are correlated with the plasma and particles with a ~30-day lag in both the supersonic wind and heliosheath.",
"doi": "10.1088/1742-6596/1100/1/012019",
"issn": "1742-6596",
"publisher": "IOP",
"publication": "Journal of Physics: Conference Series",
"publication_date": "2018-10-24",
"volume": "1100",
"pages": "Art. No. 012019"
},
{
"id": "authors:ahn06-d5974",
"collection": "authors",
"collection_id": "ahn06-d5974",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20180921-095050945",
"type": "article",
"title": "Elemental Composition at the Cosmic-Ray Source Derived from the ACE-CRIS Instrument. I. _6C to _(28)Ni",
"author": [
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Lave",
"given_name": "K. A.",
"clpid": "Lave-K-A"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We report new elemental source abundances from _6C to _(28)Ni for galactic cosmic rays, using observations from the Cosmic Ray Isotope Spectrometer (CRIS) on board the NASA Advanced Composition Explorer spacecraft. Abundances were calculated using CRIS energy spectra at energies below 550 MeV/nucleon from the 1997\u201398 and 2009\u201310 solar-minimum periods, as well as from the 2001\u201303 solar-maximum period. These new results, when combined with results for heavier elements reported in a forthcoming paper, are consistent with a model of galactic cosmic-ray origin where nuclei found in interstellar grains are accelerated preferentially over those found in interstellar gas, with this acceleration happening in OB associations.",
"doi": "10.3847/1538-4357/aad867",
"issn": "1538-4357",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2018-09-20",
"series_number": "1",
"volume": "865",
"issue": "1",
"pages": "Art. No. 69"
},
{
"id": "authors:hw75f-x3841",
"collection": "authors",
"collection_id": "hw75f-x3841",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140709-091502003",
"type": "article",
"title": "Integrated Science Investigation of the Sun (ISIS): Design of the Energetic Particle Investigation",
"author": [
{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158",
"clpid": "McComas-D-J"
},
{
"family_name": "Burnham",
"given_name": "J. A.",
"clpid": "Burnham-J-A"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Klemic",
"given_name": "J.",
"clpid": "Klemic-J"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Rankin",
"given_name": "J. S.",
"orcid": "0000-0002-8111-1444",
"clpid": "Rankin-J-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The Integrated Science Investigation of the Sun (ISIS) is a complete science investigation on the Solar Probe Plus (SPP) mission, which flies to within nine solar radii of the Sun's surface. ISIS comprises a two-instrument suite to measure energetic particles over a very broad energy range, as well as coordinated management, science operations, data processing, and scientific analysis. Together, ISIS observations allow us to explore the mechanisms of energetic particles dynamics, including their: (1) Origins\u2014defining the seed populations and physical conditions necessary for energetic particle acceleration; (2) Acceleration\u2014determining the roles of shocks, reconnection, waves, and turbulence in accelerating energetic particles; and (3) Transport\u2014revealing how energetic particles propagate from the corona out into the heliosphere. The two ISIS Energetic Particle Instruments measure lower (EPI-Lo) and higher (EPI-Hi) energy particles. EPI-Lo measures ions and ion composition from \u223c20 keV/nucleon\u201315 MeV total energy and electrons from \u223c25\u20131000 keV. EPI-Hi measures ions from \u223c1\u2013200 MeV/nucleon and electrons from \u223c0.5\u20136 MeV. EPI-Lo comprises 80 tiny apertures with fields-of-view (FOVs) that sample over nearly a complete hemisphere, while EPI-Hi combines three telescopes that together provide five large-FOV apertures. ISIS observes continuously inside of 0.25 AU with a high data collection rate and burst data (EPI-Lo) coordinated with the rest of the SPP payload; outside of 0.25 AU, ISIS runs in low-rate science mode whenever feasible to capture as complete a record as possible of the solar energetic particle environment and provide calibration and continuity for measurements closer in to the Sun. The ISIS Science Operations Center plans and executes commanding, receives and analyzes all ISIS data, and coordinates science observations and analyses with the rest of the SPP science investigations. Together, ISIS' unique observations on SPP will enable the discovery, untangling, and understanding of the important physical processes that govern energetic particles in the innermost regions of our heliosphere, for the first time. This paper summarizes the ISIS investigation at the time of the SPP mission Preliminary Design Review in January 2014.",
"doi": "10.1007/s11214-014-0059-1",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2016-12",
"series_number": "1",
"volume": "204",
"issue": "1",
"pages": "187-256"
},
{
"id": "authors:sqqfe-61v61",
"collection": "authors",
"collection_id": "sqqfe-61v61",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160422-072602817",
"type": "article",
"title": "Observation of the ^(60)Fe nucleosynthesis-clock isotope in galactic cosmic rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Lave",
"given_name": "K. A.",
"clpid": "Lave-K-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "^(60)Fe is a radioactive isotope in cosmic rays that serves as a clock to infer an upper limit on the time between nucleosynthesis and acceleration. We have used the ACE-CRIS instrument to collect 3.55 \u00d7 10^5 iron nuclei, with energies ~195 to ~500 MeV/nucleon, of which we identify 15 ^(60)Fe nuclei. The ^(60)Fe/^(56)Fe source ratio is (7.5 \u00b1 2.9) \u00d7 10^(\u22125). The detection of supernova-produced ^(60)Fe in cosmic rays implies that the time required for acceleration and transport to Earth does not greatly exceed the ^(60)Fe half-life of 2.6 Myr and that the ^(60)Fe source distance does not greatly exceed the distance cosmic rays can diffuse over this time, \u2a8d 1 kpc. A natural place for ^(60)Fe origin is in nearby clusters of massive stars.",
"doi": "10.1126/science.aad6004",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "2016-05-06",
"series_number": "6286",
"volume": "352",
"issue": "6286",
"pages": "677-680"
},
{
"id": "authors:chzt2-ykn38",
"collection": "authors",
"collection_id": "chzt2-ykn38",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160324-112710122",
"type": "article",
"title": "Diffusive Shock Acceleration and Reconnection Acceleration Processes",
"author": [
{
"family_name": "Zank",
"given_name": "G. P.",
"orcid": "0000-0002-4642-6192",
"clpid": "Zank-G-P"
},
{
"family_name": "Hunana",
"given_name": "P.",
"clpid": "Hunana-P"
},
{
"family_name": "Mostafavi",
"given_name": "P.",
"clpid": "Mostafavi-P"
},
{
"family_name": "Le Roux",
"given_name": "J. A.",
"clpid": "Le-Roux-J-A"
},
{
"family_name": "Li",
"given_name": "Gang",
"orcid": "0000-0001-9313-251X",
"clpid": "Li-Gang"
},
{
"family_name": "Webb",
"given_name": "G. M.",
"clpid": "Webb-G-M"
},
{
"family_name": "Khabarova",
"given_name": "O.",
"clpid": "Khabarova-O"
},
{
"family_name": "Cummings",
"given_name": "A.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E.",
"clpid": "Stone-E"
},
{
"family_name": "Decker",
"given_name": "R.",
"clpid": "Decker-R"
}
],
"abstract": "Shock waves, as shown by simulations and observations, can generate high levels of downstream vortical turbulence, including magnetic islands. We consider a combination of diffusive shock acceleration (DSA) and downstream magnetic-island-reconnection-related processes as an energization mechanism for charged particles. Observations of electron and ion distributions downstream of interplanetary shocks and the heliospheric termination shock (HTS) are frequently inconsistent with the predictions of classical DSA. We utilize a recently developed transport theory for charged particles propagating diffusively in a turbulent region filled with contracting and reconnecting plasmoids and small-scale current sheets. Particle energization associated with the anti-reconnection electric field, a consequence of magnetic island merging, and magnetic island contraction, are considered. For the former only, we find that (i) the spectrum is a hard power law in particle speed, and (ii) the downstream solution is constant. For downstream plasmoid contraction only, (i) the accelerated spectrum is a hard power law in particle speed; (ii) the particle intensity for a given energy peaks downstream of the shock, and the distance to the peak location increases with increasing particle energy, and (iii) the particle intensity amplification for a particular particle energy, f(x,c/c_0)/f(0,c/c_0), is not 1, as predicted by DSA, but increases with increasing particle energy. The general solution combines both the reconnection-induced electric field and plasmoid contraction. The observed energetic particle intensity profile observed by Voyager 2 downstream of the HTS appears to support a particle acceleration mechanism that combines both DSA and magnetic-island-reconnection-related processes.",
"doi": "10.1088/0004-637X/814/2/137",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2015-12-01",
"series_number": "2",
"volume": "814",
"issue": "2",
"pages": "Art. No. 137"
},
{
"id": "authors:ntq8e-m6777",
"collection": "authors",
"collection_id": "ntq8e-m6777",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151020-083336736",
"type": "article",
"title": "Precursors To Interstellar Shocks of Solar Origin",
"author": [
{
"family_name": "Gurnett",
"given_name": "D. A.",
"clpid": "Gurnett-D-A"
},
{
"family_name": "Kurth",
"given_name": "W. S.",
"clpid": "Kurth-W-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Krimigis",
"given_name": "S. M.",
"orcid": "0000-0003-2781-2386",
"clpid": "Krimigis-S-M"
},
{
"family_name": "Decker",
"given_name": "R. B.",
"clpid": "Decker-R-B"
},
{
"family_name": "Ness",
"given_name": "N. F.",
"clpid": "Ness-N-F"
},
{
"family_name": "Burlaga",
"given_name": "L. F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
}
],
"abstract": "On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the \"foreshock\" that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.",
"doi": "10.1088/0004-637X/809/2/121",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2015-08-10",
"series_number": "2",
"volume": "809",
"issue": "2",
"pages": "Art. No. 121"
},
{
"id": "authors:7fcww-ftx52",
"collection": "authors",
"collection_id": "7fcww-ftx52",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150604-140432982",
"type": "article",
"title": "Spectral Evolution of Anomalous Cosmic Rays at Voyager 1 beyond the Termination Shock",
"author": [
{
"family_name": "Senanayake",
"given_name": "U. K.",
"clpid": "Senanayake-U-K"
},
{
"family_name": "Florinski",
"given_name": "V.",
"orcid": "0000-0001-5485-2872",
"clpid": "Florinski-V"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "When the Voyager 1 spacecraft crossed the termination shock (TS) on 2004 December 16, the energy spectra of anomalous cosmic rays (ACRs) could not have been produced by steady-state diffusive shock acceleration. However, over the next few years, in the declining phase of the solar cycle, the spectra began to evolve into the expected power-law profile. Observations at the shock led to a broad range of alternative theories for ACR acceleration. In spite of that, in this work we show that the observations could be explained by assuming ACRs are accelerated at the TS. In this paper, we propose that the solar cycle had an important effect on the unrolling of the spectra in the heliosheath. To investigate the spectral evolution of ACRs, a magnetohydrodynamic background model with stationary solar-wind inner boundary conditions was used to model the transport of helium and oxygen ions. We used a backward-in-time stochastic integration technique where phase-space trajectories are integrated until the so-called \"injection energy\" is reached. Our simulation results were compared with Voyager 1 observations using three different diffusion models. It is shown that the spectral evolution of ACRs in the heliosheath at Voyager 1 could be explained by an increase in the source strength and an enhancement in diffusion as a result of a decrease of the turbulent correlation length in the declining phase of the solar cycle. At the same time, drift effects seem to have had a smaller effect on the evolution of the spectra.",
"doi": "10.1088/0004-637X/804/1/12",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2015-05-01",
"series_number": "1",
"volume": "804",
"issue": "1",
"pages": "Art. No. 12"
},
{
"id": "authors:a96e5-s3z10",
"collection": "authors",
"collection_id": "a96e5-s3z10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150518-085218576",
"type": "article",
"title": "Energetic Particle Anisotropies at the Heliospheric Boundary. II. Transient Features and Rigidity Dependence",
"author": [
{
"family_name": "Florinski",
"given_name": "V.",
"orcid": "0000-0001-5485-2872",
"clpid": "Florinski-V"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Le Roux",
"given_name": "J. A.",
"clpid": "Le-Roux-J-A"
}
],
"abstract": "In the preceding paper, we showed that large second-order anisotropies of heliospheric ions measured by the Voyager 1 space probe during the August 2012 boundary crossing event could be explained by a magnetic shear across the heliopause preventing particles streaming along the magnetic field from escaping the inner heliosheath. According to Stone et al., the penetration distance of heliospheric ions into the outer heliosheath had a strong dependence on the particle's Larmor radius. By comparing hydrogen, helium, and oxygen ions with the same energy per nucleon, these authors argued that this effect must be attributed to larger cyclotron radii of heavier species rather than differences in velocity. We propose that gradient drift in a nonuniform magnetic field was the cause of both the large second-order anisotropies and the spatial differentiation based on the ion's rigidity. A latitudinal gradient of magnetic field strength of about 10% per AU between 2012.7 and 2012.9 could have provided drift motion sufficient to match both LECP and CRS Voyager 1 observations. We explain the transient intensity dropout observed prior to the heliocliff using flux tube structures embedded in the heliosheath and magnetically connected to interstellar space. Finally, this paper reports a new indirect measurement of the plasma radial velocity at the heliopause on the basis of the time difference between two cosmic-ray telescopes measuring the same intensity dropout.",
"doi": "10.1088/0004-637X/803/1/47",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2015-04-10",
"series_number": "1",
"volume": "803",
"issue": "1",
"pages": "Art. No. 47"
},
{
"id": "authors:yya6h-gfp31",
"collection": "authors",
"collection_id": "yya6h-gfp31",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130725-143748629",
"type": "article",
"title": "Voyager 1 Observes Low-Energy Galactic Cosmic Rays in a Region Depleted of Heliospheric Ions",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Heikkila",
"given_name": "B. C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "On 25 August 2012, Voyager 1 was at 122 astronomical units when the steady intensity of low-energy ions it had observed for the previous 6 years suddenly dropped for a third time and soon completely disappeared as the ions streamed away into interstellar space. Although the magnetic field observations indicate that Voyager 1 remained inside the heliosphere, the intensity of cosmic ray nuclei from outside the heliosphere abruptly increased. We report the spectra of galactic cosmic rays down to ~3 \u00d7 10^6 electron volts per nucleon, revealing H and He energy spectra with broad peaks from 10 \u00d7 10^6 to 40 \u00d7 10^6 electron volts per nucleon and an increasing galactic cosmic-ray electron intensity down to ~10 \u00d7 10^6 electron volts.",
"doi": "10.1126/science.1236408",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "2013-07-12",
"series_number": "6142",
"volume": "341",
"issue": "6142",
"pages": "150-153"
},
{
"id": "authors:qqgnw-p8m74",
"collection": "authors",
"collection_id": "qqgnw-p8m74",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130725-072008737",
"type": "article",
"title": "Galactic Cosmic-Ray Energy Spectra and Composition during the 2009-2010 Solar Minimum Period",
"author": [
{
"family_name": "Lave",
"given_name": "K. A.",
"clpid": "Lave-K-A"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We report new measurements of the elemental energy spectra and composition of galactic cosmic rays during the 2009-2010 solar minimum period using observations from the Cosmic Ray Isotope Spectrometer (CRIS) onboard the Advanced Composition Explorer. This period of time exhibited record-setting cosmic-ray intensities and very low levels of solar activity. Results are given for particles with nuclear charge 5 \u2264 Z \u2264 28 in the energy range ~50-550 MeV nucleon^(\u20131). Several recent improvements have been made to the earlier CRIS data analysis, and therefore updates of our previous observations for the 1997-1998 solar minimum and 2001-2003 solar maximum are also given here. For most species, the reported intensities changed by less than ~7%, and the relative abundances changed by less than ~4%. Compared with the 1997-1998 solar minimum relative abundances, the 2009-2010 abundances differ by less than 2\u03c3, with a trend of fewer secondary species observed in the more recent time period. The new 2009-2010 data are also compared with results of a simple \"leaky-box\" galactic transport model combined with a spherically symmetric solar modulation model. We demonstrate that this model is able to give reasonable fits to the energy spectra and the secondary-to-primary ratios B/C and (Sc+Ti+V)/Fe. These results are also shown to be comparable to a GALPROP numerical model that includes the effects of diffusive reacceleration in the interstellar medium.",
"doi": "10.1088/0004-637X/770/2/117",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2013-06-20",
"series_number": "2",
"volume": "770",
"issue": "2",
"pages": "Art. No. 117"
},
{
"id": "authors:k90rj-5sd35",
"collection": "authors",
"collection_id": "k90rj-5sd35",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-083853990",
"type": "article",
"title": "Anomalous and Galactic Cosmic Rays at 1 AU During the Cycle 23/24 Solar Minimum",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "Anomalous cosmic ray (ACR) intensities at 1 AU at solar minimum generally track galactic cosmic ray (GCR) intensities such as those measured by neutron monitors, albeit with differences between solar polarity cycles. The unusual cycle 23/24 solar minimum was long-lasting with very low sunspot numbers and significantly reduced interplanetary magnetic field strength and solar wind dynamic pressure and turbulence, but also featured a heliospheric current sheet tilt that remained high for an extended period. Peak ACR intensities did not recover to the maximum values reached during the last two A>0 solar minima and just barely reached the last A<0 levels. However, GCR intensities in 2009 (neutron monitor rates and also at \u223c200 MeV/nucleon) were the highest recorded during the last 50 years, indicating their intensities were not as heavily modulated during their transport from the outer heliosphere. This unexpected difference in the behavior of ACRs and GCRs remains unexplained, but suggests that either the ACR source intensity may have weakened since the last A<0 epoch, or perhaps that ACR intensities at 1 AU in the ecliptic may be more sensitive than GCRs to the higher tilt angle. This seems plausible if the ACR source intensity is greater at low latitudes during A<0 cycles, while the GCR distribution at the heliospheric boundary is more uniform in latitude. Shortly after an abrupt increase in the current sheet tilt angle in late 2009, both ACR and GCR intensities showed dramatic decreases, marking the end of solar minimum modulation conditions for this cycle.",
"doi": "10.1007/s11214-011-9772-1",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2013-06",
"series_number": "1-4",
"volume": "176",
"issue": "1-4",
"pages": "253-263"
},
{
"id": "authors:a4cjf-bfp18",
"collection": "authors",
"collection_id": "a4cjf-bfp18",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121207-133222594",
"type": "article",
"title": "Large Proton Anisotropies in the 18 August 2010 Solar Particle Event",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The solar particle event observed at STEREO Ahead on 18 August 2010 displayed a rich variety of behavior in the particle anisotropies. Sectored rates measured by the Low Energy Telescope (LET) on STEREO showed very large bidirectional anisotropies in 4\u2009\u2013\u20096 MeV protons for the first \u223c\u200917 hours of the event while inside a magnetic cloud, with intensities along the field direction several hundred to nearly 1000 times greater than those perpendicular to the field. At the trailing end of the cloud, the protons became isotropic and their spectrum hardened slightly, while the He/H abundance ratio plunged by a factor of approximately four for about four hours. Associated with the arrival of a shock on 20 August was a series of brief (<\u200910 minute duration) intensity increases (commonly called \"shock spikes\") with relatively narrow angular distributions (\u223c\u200945\u2218 FWHM), followed by an abrupt decrease in particle intensities at the shock itself and a reversal of the proton flow to a direction toward the Sun and away from the receding shock. We discuss the STEREO/LET observations of this interesting event in the context of other observations reported in the literature.",
"doi": "10.1007/s11207-012-0018-5",
"issn": "0038-0938",
"publisher": "Springer",
"publication": "Solar Physics",
"publication_date": "2012-11",
"series_number": "1",
"volume": "281",
"issue": "1",
"pages": "301-318"
},
{
"id": "authors:4266a-vj606",
"collection": "authors",
"collection_id": "4266a-vj606",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120502-145049365",
"type": "article",
"title": "Sudden intensity increases and radial gradient changes of cosmic ray MeV electrons and protons observed at Voyager 1 beyond 111 AU in the heliosheath",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "Voyager 1 has entered regions of different propagation conditions for energetic cosmic rays in the outer heliosheath at a distance of about 111 AU from the Sun. The low energy 6\u201314 MeV galactic electron intensity increased by ~20% over a time period \u226410 days and the electron radial intensity gradient abruptly decreased from \u223c19%/AU to \u223c8%/AU at 2009.7 at a radial distance of 111.2 AU. At about 2011.2 at a distance of 116.6 AU a second abrupt intensity increase of \u223c25% was observed for electrons. After the second sudden electron increase the radial intensity gradient increased to 18%/AU. This large positive gradient and the \u223c13 day periodic variations of >200 MeV particles observed near the end of 2011 indicate that V1 is still within the overall heliospheric modulating region. The implications of these results regarding the proximity of the heliopause are discussed.",
"doi": "10.1029/2012GL051171",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2012-03-28",
"series_number": "6",
"volume": "39",
"issue": "6",
"pages": "Art. No. L06107"
},
{
"id": "authors:38agc-jgp60",
"collection": "authors",
"collection_id": "38agc-jgp60",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110118-090120711",
"type": "article",
"title": "Multipoint connectivity analysis of the May 2007 solar energetic particle events",
"author": [
{
"family_name": "Chollet",
"given_name": "E. E.",
"clpid": "Chollet-E-E"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Gosling",
"given_name": "J. T.",
"clpid": "Gosling-J-T"
},
{
"family_name": "Haggerty",
"given_name": "D. K.",
"orcid": "0000-0001-6395-8943",
"clpid": "Haggerty-D-K"
},
{
"family_name": "Hu",
"given_name": "Q.",
"clpid": "Hu-Q"
},
{
"family_name": "Larson",
"given_name": "D.",
"clpid": "Larson-D"
},
{
"family_name": "Lavraud",
"given_name": "B.",
"clpid": "Lavraud-B"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Opitz",
"given_name": "A.",
"clpid": "Opitz-A"
},
{
"family_name": "Roelof",
"given_name": "E. C.",
"orcid": "0000-0002-2270-0652",
"clpid": "Roelof-E-C"
},
{
"family_name": "Russell",
"given_name": "C. T.",
"orcid": "0000-0003-1639-8298",
"clpid": "Russell-C-T"
},
{
"family_name": "Sauvaud",
"given_name": "J.\u2010A.",
"clpid": "Sauvaud-J-A"
}
],
"abstract": "In May of 2007, the STEREO Ahead and Behind spacecraft, along with the ACE spacecraft situated between the two STEREO spacecraft, observed two small solar energetic particle (SEP) events. STEREO-A and -B observed nearly identical time profiles in the 19 May event, but in the 23 May event, the protons arrived significantly earlier at STEREO-A than at STEREO-B and the time-intensity profiles were markedly different. We present SEP anisotropy, suprathermal electron pitch angle and solar wind data to demonstrate distortion in the magnetic field topology produced by the passage of multiple interplanetary coronal mass ejections on 22 and 23 May, causing the two spacecraft to magnetically connect to different points back at the Sun. This pair of events illustrates the power of multipoint observations in detailed interpretation of complex events, since only a small shift in observer location results in different magnetic field line connections and different SEP time-intensity profiles.",
"doi": "10.1029/2010JA015552",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2010-12-11",
"volume": "115",
"pages": "Art. No. A12106"
},
{
"id": "authors:d0mwj-88n55",
"collection": "authors",
"collection_id": "d0mwj-88n55",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101209-103120218",
"type": "article",
"title": "Record-setting Cosmic-ray Intensities in 2009 and 2010",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
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{
"family_name": "Davis",
"given_name": "A. J.",
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{
"family_name": "Lave",
"given_name": "K. A.",
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{
"family_name": "Leske",
"given_name": "R. A.",
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{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
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{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
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{
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"given_name": "E. R.",
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{
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"given_name": "A. C.",
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{
"family_name": "de Nolfo",
"given_name": "G. A.",
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{
"family_name": "Israel",
"given_name": "M. H.",
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{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
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{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
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"abstract": "We report measurements of record-setting intensities of cosmic-ray nuclei from C to Fe, made with the Cosmic Ray Isotope Spectrometer carried on the Advanced Composition Explorer in orbit about the inner Sun-Earth Lagrangian point. In the energy interval from ~70 to ~450 MeV nucleon^(\u20131), near the peak in the near-Earth cosmic-ray spectrum, the measured intensities of major species from C to Fe were each 20%-26% greater in late 2009 than in the 1997-1998 minimum and previous solar minima of the space age (1957-1997). The elevated intensities reported here and also at neutron monitor energies were undoubtedly due to several unusual aspects of the solar cycle 23/24 minimum, including record-low interplanetary magnetic field (IMF) intensities, an extended period of reduced IMF turbulence, reduced solar-wind dynamic pressure, and extremely low solar activity during an extended solar minimum. The estimated parallel diffusion coefficient for cosmic-ray transport based on measured solar-wind properties was 44% greater in 2009 than in the 1997-1998 solar-minimum period. In addition, the weaker IMF should result in higher cosmic-ray drift velocities. Cosmic-ray intensity variations at 1 AU are found to lag IMF variations by 2-3 solar rotations, indicating that significant solar modulation occurs inside ~20 AU, consistent with earlier galactic cosmic-ray radial-gradient measurements. In 2010, the intensities suddenly decreased to 1997 levels following increases in solar activity and in the inclination of the heliospheric current sheet. We describe the conditions that gave cosmic rays greater access to the inner solar system and discuss some of their implications.",
"doi": "10.1088/2041-8205/723/1/L1",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "2010-11-01",
"series_number": "1",
"volume": "723",
"issue": "1",
"pages": "L1-L6"
},
{
"id": "authors:xsk2t-3gj23",
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"collection_id": "xsk2t-3gj23",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100830-135106755",
"type": "article",
"title": "Heavy-ion Fractionation in the Impulsive Solar Energetic Particle Event of 2002 August 20: Elements, Isotopes, and Inferred Charge States",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
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{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
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{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
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{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
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],
"abstract": "Measurements of heavy-ion elemental and isotopic composition in the energy range ~12-60 MeV nucleon^(\u20131) are reported from the Advanced Composition Explorer/Solar Isotope Spectrometer (ACE/SIS) instrument for the solar energetic particle (SEP) event of 2002 August 20. We investigate fractionation in this particularly intense impulsive event by examining the enhancements of elemental and isotopic abundance ratios relative to corresponding values in the solar wind. The elemental enhancement pattern is similar to those in other impulsive events detected by ACE/SIS and in compilations of average impulsive-event composition. For individual elements, the abundance of a heavy isotope (mass M_2) is enhanced relative to that of a lighter isotope (M_1) by a factor ~(M_(1)/M_2)^\u03b1 with \u03b1 \u2243 15. Previous studies have reported elemental abundance enhancements organized as a power law in Q/M, the ratio of estimated ionic charge to mass in the material being fractionated. We consider the possibility that a fractionation law of this form could be responsible for the isotopic fractionation as a power law in the mass ratio and then explore the implications it would have for the ionic charge states in the source material. Assuming that carbon is fully stripped (Q_C = 6), we infer mean values of the ionic charge during the fractionation process, Q_Z , for a variety of elements with atomic numbers 7 \u2264 Z \u2264 28. We find that Q_(Fe) \u2243 21-22, comparable to the highest observed values that have been reported at lower energies in impulsive SEP events from direct measurements near 1 AU. The inferred charge states as a function of Z are characterized by several step increases in the number of attached electrons, Z \u2013 Q_Z . We discuss how this step structure, together with the known masses of the elements, might account for a variety of features in the observed pattern of elemental abundance enhancements. We also briefly consider alternative fractionation laws and the relationship between the charge states we infer in the source material and those derived from in situ observations.",
"doi": "10.1088/0004-637X/719/2/1212",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2010-08-20",
"series_number": "2",
"volume": "719",
"issue": "2",
"pages": "1212-1229"
},
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"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091021-153057198",
"type": "article",
"title": "First LIGO search for gravitational wave bursts from cosmic (super)strings",
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{
"literal": "LIGO Scientific Collaboration"
}
],
"abstract": "We report on a matched-filter search for gravitational wave bursts from cosmic string cusps using LIGO data from the fourth science run (S4) which took place in February and March 2005. No gravitational waves were detected in 14.9 days of data from times when all three LIGO detectors were operating. We interpret the result in terms of a frequentist upper limit on the rate of gravitational wave bursts and use the limits on the rate to constrain the parameter space (string tension, reconnection probability, and loop sizes) of cosmic string models. Many grand unified theory-scale models (with string tension G\u00b5/c^2[approximate]10^(-6)) can be ruled out at 90% confidence for reconnection probabilities p<=10^(-3) if loop sizes are set by gravitational back reaction.",
"doi": "10.1103/PhysRevD.80.062002",
"issn": "2470-0010",
"publisher": "American Physical Society",
"publication": "Physical Review D",
"publication_date": "2009-09-23",
"series_number": "6",
"volume": "80",
"issue": "6",
"pages": "Art. No. 062002"
},
{
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"collection": "authors",
"collection_id": "e986n-xa711",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091013-093452473",
"type": "article",
"title": "Radial and latitudinal gradients of anomalous cosmic ray oxygen in the inner heliosphere",
"author": [
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"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Tranquille",
"given_name": "C.",
"clpid": "Tranquille-C"
},
{
"family_name": "Marsden",
"given_name": "R. G.",
"clpid": "Marsden-R-G"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We use data from the Ulysses, Advanced Composition Explorer, and Solar Terrestrial Relations Observatory spacecraft to determine the radial and latitudinal gradients of anomalous cosmic ray oxygen in two energy ranges from 4.5\u201315.6 MeV/nuc in the inner heliosphere for the first time during an A<0 part of the solar cycle. Using measurements from early 2007 to mid-2008, we find that the radial gradient is \u223c48 \u00b1 13%/AU, consistent with previous inferences for A<0 and larger than that determined in the inner heliosphere for A>0. The latitudinal gradient is consistent with zero and in the range \u22120.3 to 0.4%/degree, suggesting that during A<0 these particles are not able to propagate into the inner heliosphere by rapid drift along the heliospheric current sheet if the tilt of the sheet is as large as 30 degrees.",
"doi": "10.1029/2009GL039851",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2009-09-19",
"series_number": "18",
"volume": "36",
"issue": "18",
"pages": "L18103"
},
{
"id": "authors:z18q5-6p558",
"collection": "authors",
"collection_id": "z18q5-6p558",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090817-144816744",
"type": "article",
"title": "Transient intensity changes of cosmic rays beyond the heliospheric termination shock as observed at Voyager 1",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "This paper continues our studies of temporal variations of cosmic rays beyond the heliospheric termination shock (HTS) using Voyager 1 (V1) data when V1 was beyond 94 AU. This new study utilizes cosmic ray protons and electrons of several energies. Notable transient decreases of 5\u201350% are observed in galactic cosmic ray nuclei and electrons at V1 shortly after similar decreases are observed at Voyager 2 (V2) still inside the HTS. These decreases at V1 appear to be related to the large solar events in September 2005 and December 2006 and the resulting outward moving interplanetary shock. These two large interplanetary shocks were the largest observed at V2 after V1 crossed the HTS at the end of 2004. They were observed at V2 just inside the HTS at 2006.16 and 2007.43 providing timing markers for V1. From the timing of the intensity decreases observed at V1 as the shocks first reach the HTS and then later reach V1 itself, we can estimate the shock speed beyond the HTS to be between 240 and 300 km s^(\u22121) in both cases. From the timing of the decreases observed when the shock first reaches the HTS and then several months later encounters the heliopause, we can estimate the heliosheath thickness to be 31 \u00b1 4 and 37 \u00b1 6 AU, respectively, for the two sequences of three decreases seen at V1. These values, along with the distances to the HTS that are determined, give distances from the Sun to the heliopause of 121 \u00b1 4 and 124 \u00b1 6 AU, respectively.",
"doi": "10.1029/2009JA014156",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2009-07-30",
"series_number": "7",
"volume": "114",
"issue": "7",
"pages": "A07108"
},
{
"id": "authors:fef0s-40h45",
"collection": "authors",
"collection_id": "fef0s-40h45",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20091009-094741170",
"type": "article",
"title": "Elemental Composition and Energy Spectra of Galactic Cosmic Rays During Solar Cycle 23",
"author": [
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Lave",
"given_name": "K. A.",
"clpid": "Lave-K-A"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "We report improved measurements of elemental abundances and spectra for galactic cosmic-ray (GCR) nuclei obtained by the Cosmic Ray Isotope Spectrometer on board NASA's Advanced Composition Explorer (ACE) spacecraft during the minimum and maximum phases of solar cycle 23. We discuss results for particles with nuclear charge 5 \u2264 Z \u2264 28 and typical energies between 50 and 500 MeV nucleon^(\u20131). We demonstrate that a detailed \"leaky box\" Galactic propagation model combined with a spherically symmetric solar modulation model gives a good (but not perfect) fit to the observed spectra by using a solar modulation parameter of \u03c6 = 325 MV at solar minimum and \u03c6 = 900 MV at solar maximum. Although our results are generally consistent with previous measurements from space-based and balloon-based missions, there are significant differences. The large geometrical acceptance and excellent charge resolution of the instrument result in the most detailed and statistically significant record of GCR composition to date in this energy range. The measurements reported here serve as a high-precision baseline for continued studies of GCR composition, solar modulation over the solar cycle, space radiation hazards, and other applications.",
"doi": "10.1088/0004-637X/698/2/1666",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2009-06-20",
"series_number": "2",
"volume": "689",
"issue": "2",
"pages": "1666-1681"
},
{
"id": "authors:g4w6c-bz545",
"collection": "authors",
"collection_id": "g4w6c-bz545",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-101854474",
"type": "article",
"title": "The Solar Energetic Particle Event of 14 December 2006",
"author": [
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Richardson",
"given_name": "I. G.",
"orcid": "0000-0002-3855-3634",
"clpid": "Richardson-I-G"
},
{
"family_name": "Reames",
"given_name": "D. V.",
"clpid": "Reames-D-V"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "The solar energetic particle event on 14 December 2006 was observed by several near-Earth spacecraft including the Advanced Composition Explorer (ACE), STEREO A and B, SOHO and Wind. An interesting feature of this event is a series of unusual fluctuations in the particle intensity that occurred during the first few hours. These fluctuations were observed inside a magnetic cloud that originated in a solar event on 13 December and show both similarities and variations at the different spacecraft. Interestingly, the most striking difference is between observations at the two closely-separated STEREO spacecraft. In particular, large fluctuations in the proton intensity were seen by the High Energy Telescope (HET) on STEREO A, and to a lesser extent at Wind and ACE, but not by the STEREO B HET. We conclude that the differences in intensity-time profiles were caused by anisotropies in the particle distribution and the different viewing directions of the individual particle telescopes. The intensity/anisotropy variations suggest that flux tubes with different particle propagation conditions existed within this magnetic cloud despite the absence of local magnetic field signatures associated with these regions. The intensity fluctuations are similar to those occasionally seen in impulsive particle events. There were also spacecraft-to-spacecraft differences during the onset of the particle event. An initial rapid onset of energetic (>\u200940 MeV) protons was observed by the STEREO A and B spacecraft outside the magnetic cloud, but not by spacecraft such as SOHO that were already inside the magnetic cloud at this time. The latter spacecraft observed a slower, lower intensity increase. Evidently, energetic proton propagation from the solar event to the vicinity of Earth was inhibited within the magnetic cloud compared to outside.",
"doi": "10.1007/s11207-009-9353-6",
"issn": "0038-0938",
"publisher": "Springer",
"publication": "Solar Physics",
"publication_date": "2009-05",
"series_number": "1-2",
"volume": "256",
"issue": "1-2",
"pages": "443-462"
},
{
"id": "authors:r1gwt-09x60",
"collection": "authors",
"collection_id": "r1gwt-09x60",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20090918-091120378",
"type": "article",
"title": "STEREO Observations of Energetic Neutral Hydrogen Atoms During the 2006 December 5 Solar Flare",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Barghouty",
"given_name": "A. F.",
"clpid": "Barghouty-A-F"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "von-Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "We report the discovery of energetic neutral hydrogen atoms (ENAs) emitted during the X9 solar event of 2006 December 5. Beginning ~1 hr following the onset of this E79 flare, the Low Energy Telescopes (LETs) on both the STEREO A and B spacecraft observed a sudden burst of 1.6-15 MeV protons beginning hours before the onset of the main solar energetic particle event at Earth. More than 70% of these particles arrived from a longitude within \u00b110\u00b0 of the Sun, consistent with the measurement resolution. The derived emission profile at the Sun had onset and peak times remarkably similar to the GOES soft X-ray profile and continued for more than an hour. The observed arrival directions and energy spectrum argue strongly that the particle events < 5 MeV were due to ENAs. To our knowledge, this is the first reported observation of ENA emission from a solar flare/coronal mass ejection. Possible origins for the production of ENAs in a large solar event are considered. We conclude that the observed ENAs were most likely produced in the high corona and that charge-transfer reactions between accelerated protons and partially stripped coronal ions are an important source of ENAs in solar events.",
"doi": "10.1088/0004-637X/693/1/L11",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "2009-03-01",
"series_number": "1",
"volume": "693",
"issue": "1",
"pages": "L11-L15"
},
{
"id": "authors:rzfjy-c5372",
"collection": "authors",
"collection_id": "rzfjy-c5372",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WEBjgra08",
"type": "article",
"title": "Galactic cosmic ray H and He nuclei energy spectra measured by Voyagers 1 and 2 near the heliospheric termination shock in positive and negative solar magnetic polarity cycles",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "Using data from the Voyager 1 and 2 spacecraft, we have followed the intensity variations of H, He and C + O nuclei between 1998 and 2008 and determined the spectra for H and He at the time of minimum modulation in 1998, when the solar magnetic polarity was positive and again in 2008 when the solar magnetic polarity was negative. At these times these data are representative of conditions near a heliospheric termination shock assumed to be located at \u223c90 AU. Above \u223c400 MeV/nuc for He nuclei the 11-year solar modulation cycle observed at the Earth is not seen; instead there is a 22-year variation. The negative polarity cycle intensities above \u223c150 MeV/nuc are higher than those in the positive polarity cycle by a factor of 1.4\u20131.7 times for both H and He nuclei. Below \u223c100 MeV/nuc the C nuclei intensities are similar in the two cycles to within \u00b110%. These observations are compared with theoretical calculations which also show a negative to positive polarity cycle intensity difference at higher energies, most likely associated with energy changes due to drifts near the termination shock, but the comparison suggests that improved estimates of the local interstellar spectra are required.",
"doi": "10.1029/2008JA013395",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2008-10-28",
"series_number": "A10",
"volume": "113",
"issue": "A10",
"pages": "A10108"
},
{
"id": "authors:95gns-pw536",
"collection": "authors",
"collection_id": "95gns-pw536",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BINnar08",
"type": "article",
"title": "The OB association origin of galactic cosmic rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Arnould",
"given_name": "M.",
"clpid": "Arnould-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Goriely",
"given_name": "S.",
"clpid": "Goriely-S"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The isotopic abundances of neon, iron, and a number of other species in the galactic cosmic rays have been measured using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the NASA Advanced Composition Explorer (ACE) spacecraft. We compare our data to results from two-component Wolf-Rayet (WR) models. The largest deviations of galactic cosmic ray (GCR) isotope ratios from solar-system ratios predicted by these models are ^C12/^O16, ^Ne22/^Ne20, and ^Fe58/^Fe56. Our measured abundance ratios show good agreement with the model predictions. All of our measured isotopic ratios are consistent with a GCR source consisting of ~20% of WR material mixed with ~80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations, the good agreement of our data with these models strongly suggests that OB associations are the most probable source of at least a substantial fraction of GCRs. In previous work we have shown that the primary ^Ni59 (which is radioactive and decays only by electron-capture) synthesized in supernovae has decayed prior to being accelerated to GCRs, indicating a time interval between nucleosynthesis and acceleration of >10^5 yr. In this paper we describe a scenario that should allow most of the ^Ni59 to decay in the OB association environment and conclude that OB associations are the likely source of most GCRs.",
"doi": "10.1016/j.newar.2008.05.008",
"issn": "1387-6473",
"publisher": "Elsevier",
"publication": "New Astronomy Reviews",
"publication_date": "2008-10",
"series_number": "7-10",
"volume": "52",
"issue": "7-10",
"pages": "427-430"
},
{
"id": "authors:yeh9t-99d43",
"collection": "authors",
"collection_id": "yeh9t-99d43",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-095819459",
"type": "article",
"title": "An asymmetric solar wind termination shock",
"author": [
{
"family_name": "Stone",
"given_name": "Edward C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "Alan C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "Frank B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Heikkila",
"given_name": "Bryant C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "Nand",
"clpid": "Lal-N"
},
{
"family_name": "Webber",
"given_name": "William R.",
"clpid": "Webber-W-R"
}
],
"abstract": "Voyager 2 crossed the solar wind termination shock at 83.7 au in the southern hemisphere, ~10 au closer to the Sun than found by Voyager 1 in the north. This asymmetry could indicate an asymmetric pressure from an interstellar magnetic field, from transient-induced shock motion, or from the solar wind dynamic pressure. Here we report that the intensity of 4\u20135 MeV protons accelerated by the shock near Voyager 2 was three times that observed concurrently by Voyager 1, indicating differences in the shock at the two locations. (Companion papers report on the plasma, magnetic field, plasma-wave and lower energy particle observations at the shock.) Voyager 2 did not find the source of anomalous cosmic rays at the shock, suggesting that the source is elsewhere on the shock or in the heliosheath. The small intensity gradient of Galactic cosmic ray helium indicates that either the gradient is further out in the heliosheath or the local interstellar Galactic cosmic ray intensity is lower than expected.",
"doi": "10.1038/nature07022",
"issn": "0028-0836",
"publisher": "Nature Publishing Group",
"publication": "Nature",
"publication_date": "2008-07-03",
"series_number": "7200",
"volume": "454",
"issue": "7200",
"pages": "71-74"
},
{
"id": "authors:5j7d5-yr416",
"collection": "authors",
"collection_id": "5j7d5-yr416",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:SOLapj08",
"type": "article",
"title": "A novel technique to infer ionic charge states of solar energetic particles",
"author": [
{
"family_name": "Sollitt",
"given_name": "L. S.",
"clpid": "Sollitt-L-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"clpid": "Weidenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "In some large solar energetic particle (SEP) events, the intensities of higher energy SEPs decay more rapidly than at lower energies. This energy dependence varies with particle species, as would be expected if the decay timescale depended on a rigidity-dependent diffusion mean free path. By comparing the decay timescales of carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron, mean charge states are inferred for these (and other) elements in three SEP events between 1997 and 2002 at energies between 10 and 200 MeV nucleon\u22121. In a fourth event, upper limits for the charge states are inferred. The charge states of many different particle species are all consistent with a single source temperature; in two events in 1997 and 2002, the best-fit temperature is much higher than that of the corona, which could imply a contribution from solar flare material. However, comparison with lower energy iron charge states for the 1997 event implies that the observed high-energy charge state could also be understood as the result of stripping during shock acceleration in the corona.",
"doi": "10.1086/587121",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2008-05-20",
"series_number": "1",
"volume": "679",
"issue": "1",
"pages": "910-919"
},
{
"id": "authors:78tsr-fce19",
"collection": "authors",
"collection_id": "78tsr-fce19",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140908-100947326",
"type": "article",
"title": "STEREO IMPACT Investigation Goals, Measurements, and Data Products Overview",
"author": [
{
"family_name": "Luhmann",
"given_name": "J. G.",
"orcid": "0000-0003-0626-9353",
"clpid": "Luhmann-J-G"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
}
],
"abstract": "The IMPACT (In situ Measurements of Particles And CME Transients) investigation on the STEREO mission was designed and developed to provide multipoint solar wind and suprathermal electron, interplanetary magnetic field, and solar energetic particle information required to unravel the nature of coronal mass ejections and their heliospheric consequences. IMPACT consists of seven individual sensors which are packaged into a boom suite, and a SEP suite. This review summarizes the science objectives of IMPACT, the instruments that comprise the IMPACT investigation, the accommodation of IMPACT on the STEREO twin spacecraft, and the overall data products that will flow from the IMPACT measurements. Accompanying papers in this volume of Space Science Reviews highlight the individual sensor technical details and capabilities, STEREO project plans for the use of IMPACT data, and modeling activities for IMPACT (and other STEREO) data interpretation.",
"doi": "10.1007/s11214-007-9170-x",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2008-04",
"series_number": "1-4",
"volume": "136",
"issue": "1-4",
"pages": "117-184"
},
{
"id": "authors:jxjvj-d4w12",
"collection": "authors",
"collection_id": "jxjvj-d4w12",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160630-091011138",
"type": "article",
"title": "The High Energy Telescope for STEREO",
"author": [
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Reames",
"given_name": "D. V.",
"clpid": "Reames-D-V"
},
{
"family_name": "Baker",
"given_name": "R.",
"clpid": "Baker-R"
},
{
"family_name": "Hawk",
"given_name": "J.",
"clpid": "Hawk-J"
},
{
"family_name": "Nolan",
"given_name": "J.T.",
"clpid": "Nolan-J-T"
},
{
"family_name": "Ryan",
"given_name": "L.",
"clpid": "Ryan-L"
},
{
"family_name": "Shuman",
"given_name": "S.",
"clpid": "Shuman-S"
},
{
"family_name": "Wortman",
"given_name": "K.A.",
"clpid": "Wortman-K-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "The IMPACT investigation for the STEREO Mission includes a complement of Solar Energetic Particle instruments on each of the two STEREO spacecraft. Of these instruments, the High Energy Telescopes (HETs) provide the highest energy measurements. This paper describes the HETs in detail, including the scientific objectives, the sensors, the overall mechanical and electrical design, and the on-board software. The HETs are designed to measure the abundances and energy spectra of electrons, protons, He, and heavier nuclei up to Fe in interplanetary space. For protons and He that stop in the HET, the kinetic energy range corresponds to \u223c13 to 40 MeV/n. Protons that do not stop in the telescope (referred to as penetrating protons) are measured up to \u223c100 MeV/n, as are penetrating He. For stopping He, the individual isotopes 3He and 4He can be distinguished. Stopping electrons are measured in the energy range \u223c0.7\u20136 MeV.",
"doi": "10.1007/978-0-387-09649-0_14",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2008-04",
"series_number": "1-4",
"volume": "136",
"issue": "1-4",
"pages": "391-435"
},
{
"id": "authors:0ncnh-kyh91",
"collection": "authors",
"collection_id": "0ncnh-kyh91",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140908-100838268",
"type": "article",
"title": "The Low-Energy Telescope (LET) and SEP Central Electronics for the STEREO Mission",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Geier",
"given_name": "S.",
"orcid": "0000-0002-3948-9339",
"clpid": "Geier-S"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Klemic",
"given_name": "J.",
"clpid": "Klemic-J"
},
{
"family_name": "Labrador",
"given_name": "A. W.",
"orcid": "0000-0001-9178-5349",
"clpid": "Labrador-A-W"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Miyasaka",
"given_name": "H.",
"orcid": "0000-0002-8074-4186",
"clpid": "Miyasaka-Hiromasa"
},
{
"family_name": "Nguyen",
"given_name": "V.",
"clpid": "Nguyen-V"
},
{
"family_name": "Ogliore",
"given_name": "R. C.",
"clpid": "Ogliore-R-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Radocinski",
"given_name": "R. G.",
"clpid": "Radocinski-R-G"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Hawk",
"given_name": "J.",
"clpid": "Hawk-J"
},
{
"family_name": "Shuman",
"given_name": "S.",
"clpid": "Shuman-S"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wortman",
"given_name": "K.",
"clpid": "Wortman-K"
}
],
"abstract": "The Low-Energy Telescope (LET) is one of four sensors that make up the Solar Energetic Particle (SEP) instrument of the IMPACT investigation for NASA's STEREO mission. The LET is designed to measure the elemental composition, energy spectra, angular distributions, and arrival times of H to Ni ions over the energy range from \u223c3 to \u223c30 MeV/nucleon. It will also identify the rare isotope ^(3)He and trans-iron nuclei with 30\u2264Z\u226483. The SEP measurements from the two STEREO spacecraft will be combined with data from ACE and other 1-AU spacecraft to provide multipoint investigations of the energetic particles that result from interplanetary shocks driven by coronal mass ejections (CMEs) and from solar flare events. The multipoint in situ observations of SEPs and solar-wind plasma will complement STEREO images of CMEs in order to investigate their role in space weather. Each LET instrument includes a sensor system made up of an array of 14 solid-state detectors composed of 54 segments that are individually analyzed by custom Pulse Height Analysis System Integrated Circuits (PHASICs). The signals from four PHASIC chips in each LET are used by a Minimal Instruction Set Computer (MISC) to provide onboard particle identification of a dozen species in \u223c12 energy intervals at event rates of \u223c1,000 events/sec. An additional control unit, called SEP Central, gathers data from the four SEP sensors, controls the SEP bias supply, and manages the interfaces to the sensors and the SEP interface to the Instrument Data Processing Unit (IDPU). This article outlines the scientific objectives that LET will address, describes the design and operation of LET and the SEP Central electronics, and discusses the data products that will result.",
"doi": "10.1007/s11214-007-9288-x",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2008-04",
"series_number": "1-4",
"volume": "136",
"issue": "1-4",
"pages": "285-362"
},
{
"id": "authors:4fb8v-2vh68",
"collection": "authors",
"collection_id": "4fb8v-2vh68",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140908-091625580",
"type": "article",
"title": "Passage of a large interplanetary shock from the inner heliosphere to the heliospheric termination shock and beyond: Its effects on cosmic rays at Voyagers 1 and 2",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "Using data from the charged particle telescopes on V1 and V2 we have followed the progress of a large interplanetary shock as it passes V2 at a distance of 79 AU at about 2006.16, then later crosses the heliospheric termination shock finally reaching V1 at a distance \u223c100 AU. A decrease \u223c15% is observed in the V2 >70 MeV rate starting at 2006.19 and three smaller decreases starting at 2006.29, 2006.50 and 2006.86 are observed at V1. From the timing of the first two decreases at V1 we are able to determine that the average shock speed slows down at the termination shock from \u223c600 km s^(\u22121) to 210\u2013270 km s^(\u22121). Decreases of \u223c30\u201350% in anomalous He and galactic H are observed at V2 when the shock passes this location inside the termination shock. Smaller decreases are observed for both of these components when the weakened interplanetary shock passes V1 at 2006.50. These results define the extent and magnitude of solar modulation effects on cosmic rays caused by transients both inside and beyond the termination shock.",
"doi": "10.1029/2007GL031339",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2007-10",
"series_number": "20",
"volume": "34",
"issue": "20",
"pages": "Art. No. L20107"
},
{
"id": "authors:czhfs-nkf29",
"collection": "authors",
"collection_id": "czhfs-nkf29",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140905-154130174",
"type": "article",
"title": "Temporal and spectral variations of anomalous oxygen nuclei measured by Voyager 1 and Voyager 2 in the outer heliosphere",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "We have studied the temporal and spectral variations of anomalous oxygen nuclei at the Voyager 1 (V1) and 2 (V2) spacecraft in the outer heliosphere from 1990 to the present time in 2006 when V1 is now beyond the heliospheric termination shock. During this time period, the intensities increased from their lowest values in 1990\u20131991 up to a maximum in 1998\u20131999 and then decreased rapidly in 2000\u20132001 in time coincidence with the change in solar magnetic polarity from positive to negative. During the time period after 2001, significant changes in intensities and spectra are observed relative to the earlier period of positive solar magnetic polarity before 2001. It is found that the intensities of O above \u223c10 MeV/nuc at V1 after \u223c2002.0 were higher relative to the same galactic cosmic ray He intensity between 150\u2013380 MeV/nuc than in the earlier time period. As a result, by 2006 these intensities were a factor \u223c3 times those measured at the intensity maximum in 1998\u20131999 in the previous polarity cycle. The changes observed at V2 followed a similar pattern, but the relative intensity changes of O were a factor \u223c2 times greater than those observed at V1. Also, above \u223c10 MeV/nuc, the intensity changes at V1 and V2 were nearly energy independent, and the spectra at all times before and after the solar magnetic polarity change and at all modulation levels remained \u223cE^(\u22123.0\u00b10.2), possibly characteristic of a \"source\" spectrum. When V1 crossed the termination shock, no noticeable spectral or intensity changes were observed.",
"doi": "10.1029/2006JA012207",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2007-06-05",
"series_number": "A6",
"volume": "112",
"issue": "A6",
"pages": "Art. No. A06105"
},
{
"id": "authors:rbjct-m9t19",
"collection": "authors",
"collection_id": "rbjct-m9t19",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-105038224",
"type": "article",
"title": "OB Associations, Wolf-Rayet Stars, and the Origin of Galactic Cosmic Rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Arnould",
"given_name": "M.",
"clpid": "Arnould-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Goriely",
"given_name": "S.",
"clpid": "Goriely-S"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Meynet",
"given_name": "G.",
"clpid": "Meynet-G"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We have measured the isotopic abundances of neon and a number of other species in the galactic cosmic rays (GCRs) using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent results from two-component (Wolf\u2013Rayet material plus solar-like mixtures) Wolf\u2013Rayet (WR) models. The three largest deviations of galactic cosmic ray isotope ratios from solar-system ratios predicted by these models, ^(12)C/^(16)O, ^(22)Ne/^(20)Ne, and ^(58)Fe/^(56)Fe, are very close to those observed. All of the isotopic ratios that we have measured are consistent with a GCR source consisting of \u223c20% of WR material mixed with \u223c80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with WR models suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs. In previous work it has been shown that the primary ^(59)Ni (which decays only by electron-capture) in GCRs has decayed, indicating a time interval between nucleosynthesis and acceleration of >10^5 y. It has been suggested that in the OB association environment, ejecta from supernovae might be accelerated by the high velocity WR winds on a time scale that is short compared to the half-life of ^(59)Ni. Thus the ^(59)Ni might not have time to decay and this would cast doubt upon the OB association origin of cosmic rays. In this paper we suggest a scenario that should allow much of the ^(59)Ni to decay in the OB association environment and conclude that the hypothesis of the OB association origin of cosmic rays appears to be viable.",
"doi": "10.1007/s11214-007-9195-1",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "439-449"
},
{
"id": "authors:6chxg-mj695",
"collection": "authors",
"collection_id": "6chxg-mj695",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100503-155507464",
"type": "article",
"title": "An Update on Ultra-Heavy Elements in Solar Energetic Particles above 10 MeV/Nucleon",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Measurements below several MeV/nucleon from Wind/LEMT and ACE/ULEIS show that elements heavier than Zn (Z=30) can be enhanced by factors of ~100 to 1000, depending on species, in ^3He-rich solar energetic particle (SEP) events. Using the Solar Isotope Spectrometer (SIS) on ACE we find that even large SEP (LSEP) shock-accelerated events at energies from ~10 to >100 MeV/nucleon are often very iron rich and might contain admixtures of flare seed material. Studies of ultra-heavy (UH) SEPs (with Z>30) above 10 MeV/nucleon can be used to test models of acceleration and abundance enhancements in both LSEP and ^3He-rich events. We find that the long-term average composition for elements from Z=30 to 40 is similar to standard solar system values, but there is considerable event-to-event variability. Although most of the UH fluence arrives during LSEP events, UH abundances are relatively more enhanced in ^3He-rich events, with the (3410 MeV/nucleon, the most extreme event in terms of UH composition detected so far took place on 23 July 2004 and had a (34",
"doi": "10.1007/s11214-007-9191-5",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "335-340"
},
{
"id": "authors:qh4jk-q7h10",
"collection": "authors",
"collection_id": "qh4jk-q7h10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100503-100012820",
"type": "article",
"title": "Solar Elemental Composition Based on Studies of Solar Energetic Particles",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
}
],
"abstract": "Solar abundances can be derived from the composition of the solar wind and solar energetic particles (SEPs) as well as obtained through spectroscopic means. Past comparisons have suggested that all three samples agree well, when rigidity-related fractionation effects on the SEPs were accounted for. It has been known that such effects vary from one event to the next and should be addressed on an event-by-event basis. This paper examines event variability more closely, particularly in terms of energy-dependent SEP abundances. This is now possible using detailed SEP measurements spanning several decades in energy from the Ultra Low Energy Isotope Spectrometer (ULEIS) and the Solar Isotope Spectrometer (SIS) on the ACE spacecraft. We present examples of the variability of the elemental composition with energy and suggest they can be understood in terms of diffusion from the acceleration region near the interplanetary shock. By means of a spectral scaling procedure, we obtain energy-independent abundance ratios for 14 large SEP events and compare them to reported solar wind and coronal abundances as well as to previous surveys of SEP events.",
"doi": "10.1007/s11214-007-9218-y",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "183-194"
},
{
"id": "authors:03nm5-91j72",
"collection": "authors",
"collection_id": "03nm5-91j72",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100909-133903373",
"type": "article",
"title": "An Overview of the Origin of Galactic Cosmic Rays as Inferred from Observations of Heavy Ion Composition and Spectra",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "de Nolfo",
"given_name": "G. A.",
"orcid": "0000-0002-3677-074X",
"clpid": "de-Nolfo-G-A"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The galactic cosmic rays arriving near Earth, which include both stable and long-lived nuclides from throughout the periodic table, consist of a mix of stellar nucleosynthesis products accelerated by shocks in the interstellar medium (ISM) and fragmentation products made by high-energy collisions during propagation through the ISM. Through the study of the composition and spectra of a variety of elements and isotopes in this diverse sample, models have been developed for the origin, acceleration, and transport of galactic cosmic rays. We present an overview of the current understanding of these topics emphasizing the insights that have been gained through investigations in the charge and energy ranges Z \u2272 30 and E/M \u2272 1 GeV/nuc, and particularly those using data obtained from the Cosmic Ray Isotope Spectrometer on NASA's Advanced Composition Explorer mission.",
"doi": "10.1007/s11214-007-9198-y",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "415-429"
},
{
"id": "authors:emp5w-xgp42",
"collection": "authors",
"collection_id": "emp5w-xgp42",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100506-100356849",
"type": "article",
"title": "On the Differences in Composition between Solar Energetic Particles and Solar Wind",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008",
"clpid": "Desai-M-I"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Raines",
"given_name": "J.",
"clpid": "Raines-J"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Zurbuchen",
"given_name": "T. H.",
"clpid": "Zurbuchen-T-H"
}
],
"abstract": "Although the average composition of solar energetic particles (SEPs) and the bulk solar wind are similar in a number of ways, there are key differences which imply that solar wind is not the principal seed population for SEPs accelerated by coronal mass ejection (CME) driven shocks. This paper reviews these composition differences and considers the composition of other possible seed populations, including coronal material, impulsive flare material, and interplanetary CME material.",
"doi": "10.1007/s11214-007-9187-1",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "207-219"
},
{
"id": "authors:gmcfb-bbh33",
"collection": "authors",
"collection_id": "gmcfb-bbh33",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100503-093124629",
"type": "article",
"title": "Solar Isotopic Composition as Determined Using Solar Energetic Particles",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Solar energetic particles (SEPs) provide a sample of the Sun from which solar composition may be determined. Using high-resolution measurements from the Solar Isotope Spectrometer (SIS) onboard NASA's Advanced Composition Explorer (ACE) spacecraft, we have studied the isotopic composition of SEPs at energies \u226520 MeV/nucleon in large SEP events. We present SEP isotope measurements of C, O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni made in 49 large events from late 1997 to the present. The isotopic composition is highly variable from one SEP event to another due to variations in seed particle composition or due to mass fractionation that occurs during the acceleration and/or transport of these particles. We show that various isotopic and elemental enhancements are correlated with each other, discuss the empirical corrections used to account for the compositional variability, and obtain estimated solar isotopic abundances. We compare the solar values and their uncertainties inferred from SEPs with solar wind and other solar system abundances and find generally good agreement.",
"doi": "10.1007/s11214-007-9185-3",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "195-205"
},
{
"id": "authors:4nh5v-gxz69",
"collection": "authors",
"collection_id": "4nh5v-gxz69",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140716-161335184",
"type": "article",
"title": "Composition of Anomalous Cosmic Rays",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The \"classic\" anomalous cosmic ray (ACR) component originates as interstellar neutral atoms that drift into the heliosphere, become ionized and picked up by the solar wind, and carried to the outer heliosphere where the pickup ions are accelerated to hundreds of MeV, presumably at the solar wind termination shock. These interstellar ACRs are predominantly singly charged, although higher charge states are present and become dominant above \u223c350 MeV. Their isotopic composition is like that of the solar system and unlike that of the source of galactic cosmic rays. A comparison of their energy spectra with the estimated flux of pickup ions flowing into the termination shock reveals a mass-dependent acceleration efficiency that favors heavier ions. There is also a heliospheric ACR component as evidenced by \"minor\" ACR ions, such as Na, Mg, S, and Si that appear to be singly-ionized ions from a source likely in the outer heliosphere.",
"doi": "10.1007/s11214-007-9161-y",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2007-06",
"series_number": "1-4",
"volume": "130",
"issue": "1-4",
"pages": "389-399"
},
{
"id": "authors:5f29p-crk70",
"collection": "authors",
"collection_id": "5f29p-crk70",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150324-133810503",
"type": "article",
"title": "Anomalous cosmic rays in the distant heliosphere and the reversal of the Sun's magnetic polarity in Cycle 23",
"author": [
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Heikkila",
"given_name": "B. C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "Beginning in early June 2001 and extending over a \u223c3 month period the Cosmic Ray Subsystem (CRS) experiment on Voyager 1 (80.3 AU, 34\u00b0N) observed a rapid transition in the energy of the peak intensity of anomalous cosmic ray (ACR) He from \u223c11 MeV/n to \u223c25 MeV/n. One month later there began a similar spectral shift at Voyager 2 (64.7 AU, 24\u00b0S). When these ACR transition times are extrapolated back from the estimated location of the heliospheric termination shock (TS) to the Sun (\u223c1 year) there is reasonable agreement with the range of times obtained for the polarity reversal of the interplanetary magnetic field (IPB) in the northern hemisphere near the Sun and the later reversal in the south. We interpret these changes in the ACR spectra as giving a global view of the interplanetary field reversal at the TS and confirmation of the important role of the TS in controlling the ACRs.",
"doi": "10.1029/2006GL028932",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2007-03-07",
"series_number": "5",
"volume": "34",
"issue": "5",
"pages": "Art. No. L05105"
},
{
"id": "authors:nyzka-vxa38",
"collection": "authors",
"collection_id": "nyzka-vxa38",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:BINjpcs06",
"type": "article",
"title": "Superbubbles, Wolf-Rayet stars, and the origin of galactic cosmic rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"clpid": "Weidenbeck-M-E"
},
{
"family_name": "Arnould",
"given_name": "M.",
"clpid": "Arnould-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Goriely",
"given_name": "S.",
"clpid": "Goriely-S"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Meynet",
"given_name": "G.",
"clpid": "Meynet-G"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The abundances of neon and several other isotopic ratios in the galactic cosmic rays (GCRs) have been measured using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). We have derived the 22Ne/20Ne ratio at the cosmic-ray source using the measured 21Ne, 19F, and 17O abundances as \"tracers\" of secondary isotope production. Using this approach, the 22Ne/20Ne abundance ratio obtained for the cosmic-ray source is 0.387 \u00b1 0.007 (stat.) \u00b1 0.022 (syst.). This corresponds to an enhancement by a factor of 5.3\u00b10.3 over the 22Ne/20Ne ratio in the solar wind. We compare our data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (WR) models. The three largest deviations of GCR isotope ratios from solar system ratios predicted by these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are present in the GCRs. In fact, all of the isotope ratios that we have measured are consistent with a GCR source consisting of about 80% material with solar-system composition and about 20% of WR material. Since WR stars are evolutionary products of O and B stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with WR models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.",
"doi": "10.1088/1742-6596/47/1/008",
"issn": "1742-6596",
"publisher": "Journal of Physics: Conference Series",
"publication": "Journal of Physics: Conference Series",
"publication_date": "2006-12",
"volume": "47",
"pages": "68-77"
},
{
"id": "authors:nktpg-hyy18",
"collection": "authors",
"collection_id": "nktpg-hyy18",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140407-091931371",
"type": "article",
"title": "Source and consequences of a large shock near 79 AU",
"author": [
{
"family_name": "Richardson",
"given_name": "J. D.",
"orcid": "0000-0003-4041-7540",
"clpid": "Richardson-J-D"
},
{
"family_name": "Liu",
"given_name": "Y.",
"clpid": "Liu-Y"
},
{
"family_name": "Wang",
"given_name": "C.",
"clpid": "Wang-C"
},
{
"family_name": "McComas",
"given_name": "D. J.",
"orcid": "0000-0001-6160-1158",
"clpid": "McComas-D-J"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Burlaga",
"given_name": "L. F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
},
{
"family_name": "Acuna",
"given_name": "M. H.",
"clpid": "Acuna-M-H"
},
{
"family_name": "Ness",
"given_name": "N. F.",
"clpid": "Ness-N-F"
}
],
"abstract": "In March 2006, Voyager 2 (V2) observed a large interplanetary (IP) shock near 79 AU followed by a merged interaction region (MIR). This shock is comparable to the shock observed by V2 at 65 AU in October 2001; these two shocks are the largest observed by V2 since 1991 when V2 was at 35 AU. This shock provides the first opportunity to compare the plasma structure in an IP shock and MIR with the energetic particle fluxes in the termination shock (TS) foreshock region. The flux of >0.5 MeV particles observed by V2 decreased after the shock; the shock and MIR probably pushed the TS outward so that the foreshock region moved outside the distance of V2. The >70 MeV cosmic ray ions decreased in the MIR, probably due to the reduced inward transport caused by the enhanced magnetic field. We model two possible sources of this shock, fast streams from polar coronal holes and coronal mass ejections (CMEs); these sources, when combined, provide a reasonable match to the V2 data.",
"doi": "10.1029/2006GL027983",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2006-12",
"series_number": "23",
"volume": "33",
"issue": "23",
"pages": "Art. No. L23107"
},
{
"id": "authors:zan2e-rsh70",
"collection": "authors",
"collection_id": "zan2e-rsh70",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-155626084",
"type": "article",
"title": "Correlation between energetic ion enhancements and heliospheric current sheet crossings in the outer heliosphere",
"author": [
{
"family_name": "Richardson",
"given_name": "J. D.",
"orcid": "0000-0003-4041-7540",
"clpid": "Richardson-J-D"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Kasper",
"given_name": "J. C.",
"orcid": "0000-0002-7077-930X",
"clpid": "Kasper-J-C"
},
{
"family_name": "Zhang",
"given_name": "M.",
"clpid": "Zhang-M"
},
{
"family_name": "Burlaga",
"given_name": "L. F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
},
{
"family_name": "Ness",
"given_name": "N. F.",
"clpid": "Ness-N-F"
},
{
"family_name": "Liu",
"given_name": "Y.",
"clpid": "Liu-Y"
}
],
"abstract": "Voyagers 1 and 2 observed highly-variable beams of energetic ions in the foreshock region upstream of the termination shock (TS). At Voyager 2 (V2), the ion intensities are generally not related to the plasma properties. At Voyager 1 (V1), the beams are often coincident with crossings of the heliospheric current sheet (HCS). The V1 intensity peaks occur when the HCS is crossed from negative to positive magnetic polarities and V1 is within a few AU of the TS. Two mechanisms are considered: current sheet drift and streaming of ions from the TS along magnetic field lines which are parallel to the HCS. The current sheet drift hypothesis predicts that enhancements observed at V2 will occur when the HCS is crossed in the opposite direction, from positive to negative magnetic polarity, since V2 is at southern heliolatitudes.",
"doi": "10.1029/2006GL027578",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2006-11-14",
"series_number": "21",
"volume": "33",
"issue": "21",
"pages": "Art. No. L21112"
},
{
"id": "authors:kap4x-tqq13",
"collection": "authors",
"collection_id": "kap4x-tqq13",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20110120-162201593",
"type": "article",
"title": "Wolf-Rayet stars, OB associations, and the origin\n of galactic cosmic rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Arnould",
"given_name": "M.",
"clpid": "Arnould-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Goriely",
"given_name": "S.",
"clpid": "Goriely-S"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Meynet",
"given_name": "G.",
"clpid": "Meynet-G"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We have measured the isotopic abundances of neon and several refractory species in the galactic cosmic rays (GCRs) using the cosmic\nray isotope spectrometer (CRIS) aboard the ACE spacecraft. The ^(22)Ne/^(20)Ne ratio at the cosmic-ray source that we have obtained is\n0.387 \u00b1 0.007 (stat.) \u00b1 0.022 (syst.), which corresponds to enhancement by a factor of 5.3 \u00b1 0.3 over that in the solar wind. Our\nACE-CRIS data, and data from other experiments, are compared to recent results from two-component Wolf-Rayet (WR) models.\nThe three largest deviations of galactic cosmic ray isotope ratios from solar-system ratios predicted by these models, ^(12)C/^(16)O,^(22)Ne/^(20)Ne,\nand ^(58)Fe/^(56)Fe, are, in fact, very close to those observed. Furthermore, all of the isotope ratios that we have measured are consistent with\na GCR source consisting of ~20% of WR material mixed with ~80% material with solar-system composition. Since WR stars are evolutionary\nproducts of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with\nWR models suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs.",
"doi": "10.1016/j.newar.2006.06.058",
"issn": "1387-6473",
"publisher": "Elsevier",
"publication": "New Astronomy Reviews",
"publication_date": "2006-10",
"series_number": "7-8",
"volume": "50",
"issue": "7-8",
"pages": "516-520"
},
{
"id": "authors:dhn00-s9g22",
"collection": "authors",
"collection_id": "dhn00-s9g22",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140407-093553418",
"type": "article",
"title": "The disappearance of anomalous protons at Voyager 1 and Voyager 2 in the outer heliosphere between 1998 and 2002",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
}
],
"abstract": "In 1998 and 1999 at V1 and V2 in the outer heliosphere between 55 and 75 AU, large intensities of anomalous H were observed with a peak in the differential energy spectrum at \u223c25 MeV. Subsequently, in 2000 and 2001 when these spacecraft were 5\u201310 AU further out, these intensities were greatly reduced by 11-year modulation effects, so that by the beginning of 2002 anomalous H had completely disappeared beneath the E^(1.0) spectrum of galactic H at low energies. The modulation between 1998 and 2002 produced intensity changes of galactic H similar to those observed at the Earth in the same time period except that the changes at V1 and V2 were much smaller. The intensity change at V2 was also larger than that at V1. For anomalous H, however, the intensity changes at V1 and V2 were a factor of 10\u201320 times larger than those for galactic H, so that by the end of 2001 the anomalous H intensities were less than 1% of their 1998 values. Also, during one time period in late 2001 there was a large reduction of anomalous H at both V1 and V2 with no corresponding change in galactic H. These different intensity changes between galactic and anomalous H provide an insight into particle transport, drift, and acceleration processes in the region near the heliospheric termination shock, which is located just beyond V1. Radial gradient comparisons in 1998 and also at the times of reduced anomalous H intensities imply that most of the intensity reduction of anomalous H apparently occurred at \u223c90 AU or beyond. This could indicate source changes in the anomalous H spectra but most likely is a measure of changes in the \"connection\" between V1 and V2 and the source region, such as might be caused by changing drift patterns and particle entry into the heliosphere.",
"doi": "10.1029/2006JA011669",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2006-08-26",
"series_number": "A8",
"volume": "111",
"issue": "A8",
"pages": "Art. No. A08107"
},
{
"id": "authors:dc38s-4x526",
"collection": "authors",
"collection_id": "dc38s-4x526",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-093644016",
"type": "article",
"title": "Cosmic-Ray Neon, Wolf-Rayet Stars, and the Superbubble Origin of Galactic Cosmic Rays",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Arnould",
"given_name": "M.",
"clpid": "Arnould-M"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Goriely",
"given_name": "S.",
"clpid": "Goriely-S"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Meynet",
"given_name": "G.",
"clpid": "Meynet-G"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We report the abundances of neon isotopes in the Galactic cosmic rays (GCRs) using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). These abundances have been measured for seven energy intervals over the energy range of 84 \u2264 E/M \u2264 273 MeV nucleon^(-1). We have derived the ^(22)Ne/^(20)Ne ratio at the cosmic-ray source using the measured ^(21)Ne, ^(19)F, and ^(17)O abundances as \"tracers\" of secondary production of the neon isotopes. Using this approach, the ^(22)Ne/^(20)Ne abundance ratio that we obtain for the cosmic-ray source is 0.387 \u00b1 0.007(statistical) \u00b1 0.022(systematic). This corresponds to an enhancement by a factor of 5.3 \u00b1 0.3 over the ^(22)Ne/^(20)Ne ratio in the solar wind. This cosmic-ray source ^(22)Ne/^(20)Ne ratio is also significantly larger than that found in anomalous cosmic rays, solar energetic particles, most meteoritic samples of matter, and interplanetary dust particles. We compare our ACE CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (W-R) models. The three largest deviations of GCR isotope ratios from solar system ratios predicted by these models, ^(12)C/^(16)O, ^(22)Ne/^(20)Ne, and ^(58)Fe/^(56)Fe, are indeed present in the GCRs. In fact, all of the isotope ratios that we have measured are consistent with a GCR source consisting of about 80% material with solar system composition and about 20% W-R material. Since W-R stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with W-R models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.",
"doi": "10.1086/496959",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2005-11-20",
"series_number": "1",
"volume": "634",
"issue": "1",
"pages": "351-364"
},
{
"id": "authors:rb184-jnt10",
"collection": "authors",
"collection_id": "rb184-jnt10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-084449577",
"type": "article",
"title": "Voyager 1 Explores the Termination Shock Region and the Heliosheath Beyond",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Heikkila",
"given_name": "B. C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "Voyager 1 crossed the termination shock of the supersonic flow of the solar wind on 16 December 2004 at a distance of 94.01 astronomical units from the Sun, becoming the first spacecraft to begin exploring the heliosheath, the outermost layer of the heliosphere. The shock is a steady source of low-energy protons with an energy spectrum \u223cE^(\u20131.41 \u00b1 0.15) from 0.5 to \u223c3.5 megaelectron volts, consistent with a weak termination shock having a solar wind velocity jump ratio r = 2.6^(+0.4)_(-0.2). However, in contradiction to many predictions, the intensity of anomalous cosmic ray (ACR) helium did not peak at the shock, indicating that the ACR source is not in the shock region local to Voyager 1. The intensities of \u223c10\u2013megaelectron volt electrons, ACRs, and galactic cosmic rays have steadily increased since late 2004 as the effects of solar modulation have decreased.",
"doi": "10.1126/science.1117684",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "2005-09-23",
"series_number": "5743",
"volume": "309",
"issue": "5743",
"pages": "2017-2020"
},
{
"id": "authors:459jm-wtt31",
"collection": "authors",
"collection_id": "459jm-wtt31",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140407-101736587",
"type": "article",
"title": "Heavy ion abundances and spectra from the large solar energetic particle events of October-November 2003",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008",
"clpid": "Desai-M-I"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "Observations from the Solar Isotope Spectrometer and the Ultra Low Energy Isotope Spectrometer on the ACE spacecraft during the extremely large events of October and November 2003 are combined to create heavy ion spectra over more than 3 decades in energy. The resulting spectra differed substantially in shape from event to event, as well as from element to element within a given event, resulting in energy-dependent abundance ratios. Although the effects of strong local shock acceleration are apparent in the intensities of the 28 and 29 October events, these do not explain the order of magnitude differences between the event-integrated abundances obtained at 0.64\u20130.91 MeV/nucleon and those at 12\u201360 MeV/nucleon. The higher-energy abundances relative to the lower-energy ones show trends with nuclear charge or charge-to-mass ratio that are similar for all the events and suggest that heavier ions are less efficiently accelerated to high energies. The position of the breaks in the energy spectra of O, Ne, Mg, Si, S, Ca, and Fe can be understood in terms of leakage from the shock region, if the mean free path is assumed to be a power law in rigidity. The resulting rigidity dependence is consistent with a source of wave turbulence in the vicinity of the shock when the ions are accelerated.",
"doi": "10.1029/2005JA011004",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2005-08-10",
"series_number": "A9",
"volume": "110",
"issue": "A9",
"pages": "Art. No. A09S16"
},
{
"id": "authors:xp7nb-pzr89",
"collection": "authors",
"collection_id": "xp7nb-pzr89",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150324-090430351",
"type": "article",
"title": "Differences in the spectra of anomalous cosmic ray helium nuclei in two solar magnetic polarity cycles",
"author": [
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "Heikkila",
"given_name": "B.",
"clpid": "Heikkila-B-C"
}
],
"abstract": "We compare the spectra of anomalous He nuclei measured in the heliosphere by the IMP, Voyager, and Pioneer spacecraft at heliospheric distances ranging from 1 to over 80 AU in the time period from 1977 to 2003. Striking differences in the energy spectra of these nuclei are found between positive and negative solar magnetic polarity cycles. These differences are such that the spectra observed in negative polarity cycles appear to be greatly deficient in particles with energies of less than \u223c15 MeV but have an excess intensity above >25 MeV, relative to the spectra observed in positive cycles. These spectral differences are complex and may be related to both solar modulation effects inside of the heliospheric termination shock as well as differences occurring at or near the termination shock itself. At the modulation minimum in 1998 when V2 was at a distance of 56 AU and V1 at 71 AU, a high intensity of low-energy anomalous He particles was observed with a peak in the spectrum at \u223c5 MeV/nuc. In late 2001 after the solar magnetic polarity had changed from positive to negative and the 11-year solar modulation had increased, the previous high intensities of the anomalous He nuclei seen in 1998 were greatly reduced at both V1 and V2, and the energy of the peak intensity had moved up to \u223c20\u201325 MeV/nuc. However, in both polarity periods the highest-energy part of this spectrum above \u223c30 MeV/nuc is similar with a slope of \u22122.8 \u00b1 0.2. The details of these complex spectral changes are described in this paper.",
"doi": "10.1029/2005JA011123",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2005-07-27",
"series_number": "A7",
"volume": "110",
"issue": "A7",
"pages": "Art. No. A07106"
},
{
"id": "authors:8fq5g-pz718",
"collection": "authors",
"collection_id": "8fq5g-pz718",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-114144077",
"type": "article",
"title": "Isotopic Composition of Cosmic Rays: Results from the Cosmic Ray Isotope Spectrometer on the ACE Spacecraft",
"author": [
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "The Cosmic Ray Isotope Spectrometer on the ACE spacecraft measures the isotopic composition of cosmic-ray elements from Li through Zn with an unprecedented combination of excellent mass resolution and high statistics. The results indicate a cosmic-ray source whose composition is remarkably similar to that of the solar system, but which is enriched in material that may have originated in Wolf-Rayet stars. The lack of ^(59)Ni is strong indication that the cosmic rays are accelerated at least 10^5 years after nucleosynthesis. We examine these results in the context of the superbubble model of cosmic-ray origin that has been described by Higdon and Lingenfelter.",
"doi": "10.1016/j.nuclphysa.2005.05.038",
"issn": "0375-9474",
"publisher": "Elsevier",
"publication": "Nuclear Physics A",
"publication_date": "2005-07-25",
"volume": "758",
"pages": "201-208"
},
{
"id": "authors:y72v2-bm013",
"collection": "authors",
"collection_id": "y72v2-bm013",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-134905200",
"type": "article",
"title": "IMPACT: Science goals and firsts with STEREO",
"author": [
{
"family_name": "Luhmann",
"given_name": "J. G.",
"orcid": "0000-0003-0626-9353",
"clpid": "Luhmann-J-G"
},
{
"family_name": "Cummings",
"given_name": "A.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Davis",
"given_name": "A.",
"clpid": "Davis-A"
}
],
"abstract": "The in situ measurements of particles and CME transients (IMPACT) investigation on the twin STEREO spacecraft focuses on the solar energetic particle, solar wind and suprathermal electron, and magnetic field measurements needed to address STEREO's goals. IMPACT will provide regular, identical, in situ multipoint measurements bracketing Earth as each spacecraft separates from it at a rate of \u223c22\u00b0/yr along Earth's orbit. Combined with the PLASTIC and SWAVES investigations, IMPACT fills a critical role in the STEREO quest to connect SECCHI's 3D coronal images to their interplanetary consequences.",
"doi": "10.1016/j.asr.2005.03.033",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2005",
"series_number": "8",
"volume": "36",
"issue": "8",
"pages": "1534-1543"
},
{
"id": "authors:b774t-yeg31",
"collection": "authors",
"collection_id": "b774t-yeg31",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140319-135713728",
"type": "article",
"title": "Do Anomalous Cosmic Rays Modify the Termination Shock?",
"author": [
{
"family_name": "Florinski",
"given_name": "V.",
"orcid": "0000-0001-5485-2872",
"clpid": "Florinski-V"
},
{
"family_name": "Zank",
"given_name": "G. P.",
"orcid": "0000-0002-4642-6192",
"clpid": "Zank-G-P"
},
{
"family_name": "Jokipii",
"given_name": "J. R.",
"clpid": "Jokipii-J-R"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
}
],
"abstract": "This work extends our previous two-dimensional self-consistent model of the cosmic rays interacting with the solar wind to include anomalous cosmic rays. As before, energetic particles are described kinetically using a Parker equation. The model includes diffusion, convection, and drift effects, as well as shock and compression acceleration and expansion cooling by nonuniform solar wind flow. A new numerical model has been developed featuring an adaptive-mesh refinement algorithm to accommodate small diffusive length scales of low-energy shock-accelerated particles. We show that anomalous cosmic rays have only a minor effect on the termination shock during the time near solar minima. Specifically, cosmic-ray gradients cause the subshock to move away from the Sun by about 1 AU with its compression ratio decreasing by about 5% compared to the reference case without cosmic-ray effects. We also study the effect of solar wind slowdown by charge exchange downstream of the termination shock, producing compressive flow in this region and resulting in additional acceleration of anomalous cosmic rays in the heliosheath. For the first time, spectra calculated with our self-consistent model show a good agreement with the cosmic-ray data from the two Voyager spacecraft, giving more confidence in the model predictions than the previous parametric studies.",
"doi": "10.1086/421901",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2004-08-01",
"series_number": "2",
"volume": "610",
"issue": "2",
"pages": "1169-1181"
},
{
"id": "authors:w96r6-sa675",
"collection": "authors",
"collection_id": "w96r6-sa675",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-084638532",
"type": "article",
"title": "Enhancements of energetic particles near the heliospheric termination shock",
"author": [
{
"family_name": "McDonald",
"given_name": "Frank B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Stone",
"given_name": "Edward C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "Alan C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Heikkila",
"given_name": "Bryant C.",
"clpid": "Heikkila-B-C"
},
{
"family_name": "Lal",
"given_name": "Nand",
"clpid": "Lal-N"
},
{
"family_name": "Webber",
"given_name": "William R.",
"clpid": "Webber-W-R"
}
],
"abstract": "The spacecraft Voyager 1 is at a distance greater than 85 au from the Sun, in the vicinity of the termination shock that marks the abrupt slowing of the supersonic solar wind and the beginning of the extended and unexplored distant heliosphere. This shock is expected to accelerate 'anomalous cosmic rays', as well as to re-accelerate Galactic cosmic rays and low-energy particles from the inner Solar System. Here we report a significant increase in the numbers of energetic ions and electrons that persisted for seven months beginning in mid-2002. This increase differs from any previously observed in that there was a simultaneous increase in Galactic cosmic ray ions and electrons, anomalous cosmic rays and low-energy ions. The low-intensity level and spectral energy distribution of the anomalous cosmic rays, however, indicates that Voyager 1 still has not reached the termination shock. Rather, the observed increase is an expected precursor event. We argue that the radial anisotropy of the cosmic rays is expected to be small in the foreshock region, as is observed.",
"doi": "10.1038/nature02066",
"issn": "0028-0836",
"publisher": "Nature Publishing Group",
"publication": "Nature",
"publication_date": "2003-11-06",
"series_number": "6962",
"volume": "426",
"issue": "6962",
"pages": "48-51"
},
{
"id": "authors:whjpk-25631",
"collection": "authors",
"collection_id": "whjpk-25631",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-091516862",
"type": "article",
"title": "Elemental Fractionation in Small Solar Energetic Particle Events",
"author": [
{
"family_name": "Slocum",
"given_name": "P. L.",
"clpid": "Slocum-P-L"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Desai",
"given_name": "M. I.",
"orcid": "0000-0002-7318-6008",
"clpid": "Desai-M-I"
},
{
"family_name": "Dwyer",
"given_name": "J. R.",
"clpid": "Dwyer-J-R"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "Using the Solar Isotope Spectrometer on the Advanced Composition Explorer (ACE), we have measured the 11.0-21.8 MeV nucleon^(-1) heavy (Z \u2265 6) element abundances of 39 small solar energetic particle (SEP) events that occurred between 1998 April 3 and 2002 February 26. Using He isotope data from the Ultra-Low-Energy Isotope Spectrometer on ACE, we have classified the events according to their 0.5-2.0 MeV nucleon^(-1) ^3He/^4He ratios. We find that their average heavy-element composition is similar to that of either large gradual events or ^3He-rich events, depending on their ^3He/^4He ratio. As seen in recent studies of small SEP events, we find that the heavy-element intensities relative to C increase with the ^3He/^4He ratios. The dependence of the heavy-element abundances on first ionization potential (FIP) has been derived, using a model consisting of a power law in Q/M (and Z) times a step function in FIP. We report the magnitude of the FIP factor in each event and find that it varies from ~2 to 7 with no clear dependence on the ^3He/^4He ratio.",
"doi": "10.1086/376755",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2003-09-01",
"series_number": "1",
"volume": "594",
"issue": "1",
"pages": "592-604"
},
{
"id": "authors:c0tt0-3fd60",
"collection": "authors",
"collection_id": "c0tt0-3fd60",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-164919486",
"type": "article",
"title": "Cosmic ray energy loss in the heliosphere: Direct evidence from electron-capture-decay secondary isotopes",
"author": [
{
"family_name": "Niebur",
"given_name": "S. M.",
"clpid": "Niebur-S-M"
},
{
"family_name": "Scott",
"given_name": "L. M.",
"clpid": "Scott-L-M"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "Measurements by the Cosmic Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer (ACE) spacecraft provide direct evidence that galactic cosmic rays lose energy as a result of their interactions with magnetic fields expanding with the solar wind. The secondary isotopes ^(49)V and ^(51)Cr can decay to ^(49)Ti and ^(51)V, respectively, only by electron capture. The observed abundances of these isotopes are directly related to the probability of attaching an electron from the interstellar medium; this probability decreases strongly with increasing energy around a few hundred MeV/nucleon. At the highest energies observed by CRIS, electron attachment on these nuclides is very unlikely, and thus ^(49)V and ^(51)Cr are essentially stable. At lower energies, attachment and decay do occur. Comparison of the energy dependence of the daughter/parent ratios ^(49)Ti/^(49)V and ^(51)V/^(51)Cr during solar minimum and solar maximum conditions confirms that increased energy loss occurs during solar maximum. This analysis indicates an increase in the modulation parameter \u03d5 of about 400 to 700 MV corresponding to an increase in average energy loss for these elements of about 200 to 300 MeV/nucleon.",
"doi": "10.1029/2003JA009876",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2003-08-19",
"series_number": "A10",
"volume": "108",
"issue": "A10",
"pages": "Art. No. 8033"
},
{
"id": "authors:9taz6-5ee10",
"collection": "authors",
"collection_id": "9taz6-5ee10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-090049799",
"type": "article",
"title": "Variability of spectra in large solar energetic particle events",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "Using data from the Solar Isotope Spectrometer on the Advanced Composition Explorer obtained during 36large solar energetic particle events (SEPs) that occurred during 1997\u20132002 we have examined the spectral characteristics of oxygen and iron. Based on the shape of the oxygen spectrum during the decay phase following the peak in particle intensity, each SEP event was categorized as either exponential (7 events) or power law (29 events). We find that the exponential events were typically the larger events (in terms of peak oxygen intensity) and had Fe/O ratios that strongly decreased with increasing energy. Event-averaged Fe/O ratios (integrated over 12 to 60 MeV/nucleon) were at or below coronal abundances for nearly all these events, while the ratios obtained in the power law events were typically enhanced over coronal values. The majority of the power law events had the same spectral index for both O and Fe resulting in an Fe/O ratio independent of energy. However 6 of the 29 power law events had Fe/O ratios that increased with increasing energy due to an Fe spectral index less negative than that of O. We consider simple diffusion theory in an effort to understand the nature of these events and obtain preliminary but promising results.",
"doi": "10.1016/S0273-1177(03)00901-3",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2003",
"series_number": "12",
"volume": "32",
"issue": "12",
"pages": "2649-2654"
},
{
"id": "authors:wwa1c-x2d25",
"collection": "authors",
"collection_id": "wwa1c-x2d25",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150304-160334774",
"type": "article",
"title": "Erratum: Composition of Anomalous Cosmic Rays and Other Heliospheric Ions",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Steenberg",
"given_name": "C. D.",
"clpid": "Steenberg-C-D"
}
],
"doi": "10.1086/345507",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2002-12-20",
"series_number": "2",
"volume": "581",
"issue": "2",
"pages": "1413-1413"
},
{
"id": "authors:qtnkm-r3t34",
"collection": "authors",
"collection_id": "qtnkm-r3t34",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140226-144958207",
"type": "article",
"title": "Composition of Anomalous Cosmic Rays and Other Heliospheric Ions",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Steenberg",
"given_name": "C. D.",
"clpid": "Steenberg-C-D"
}
],
"abstract": "Interstellar pickup ions accelerated by the termination shock of the solar wind dominate the anomalous cosmic-ray (ACR) intensities observed by the Voyager spacecraft in the outer heliosphere. Using a two-dimensional acceleration and propagation model, we derive the relative abundances of these interstellar ACRs and determine the mass dependence of the injection/acceleration efficiency for the diffusive acceleration of H^+, He^+, N^+, O^+, and Ne^+. The energy spectra of C, Na, Mg, Si, S, and Ar also exhibit ACR increases at low energies. To interpret these observations, we have developed a new set of ionization rates for 11 neutral atoms, H, He, C, N, O, Ne, Na, Mg, Si, S, and Ar at 1 AU, and a new set of filtration factors relating neutral densities in the local interstellar medium to those at the location of the solar wind termination shock. Using the injection/acceleration efficiencies and the Ar filtration factor, we estimate the density of neutral Ar to be (3.5 \u00b1 1.6) \u00d7 10^(-7) cm^(-3) in the local interstellar medium. ACR C may have a significant contribution from interstellar neutral C, but the observed intensities of ACR Na, Mg, Si, and S significantly exceed that expected from interstellar neutrals, providing evidence of another source of pickup ions. One possibility discussed is the recently discovered \"inner source\" of singly charged ions that is thought to be solar wind atoms desorbed from interplanetary dust grains.",
"doi": "10.1086/342427",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2002-10-10",
"series_number": "1",
"volume": "578",
"issue": "1",
"pages": "194-210"
},
{
"id": "authors:nemk2-dq215",
"collection": "authors",
"collection_id": "nemk2-dq215",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-085036707",
"type": "article",
"title": "Spectral Properties of He and Heavy Ions in ^3He-rich Solar Flares",
"author": [
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Miller",
"given_name": "J. A.",
"clpid": "Miller-J-A"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Dwyer",
"given_name": "J. R.",
"clpid": "Dwyer-J-R"
},
{
"family_name": "Gold",
"given_name": "R. E.",
"clpid": "Gold-R-E"
},
{
"family_name": "Krimigis",
"given_name": "S. M.",
"orcid": "0000-0003-2781-2386",
"clpid": "Krimigis-S-M"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Slocum",
"given_name": "P. L.",
"clpid": "Slocum-P-L"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Using advanced instrumentation on the ACE spacecraft, we have conducted a survey of solar energetic particle spectra in ^3He-rich events over a broad energy range ~80 keV nucleon^(-1) to 15 MeV nucleon^(-1) during the period 1997 September-2001 March. The spectra of ^4He and heavy ions (C, N, O, Ne, Mg, Si, S, Ca, Fe) were generally similar over this range but often hardened below ~1 MeV nucleon^(-1). In most of the events there was even stronger hardening of the ^3He spectrum below ~1 MeV nucleon^(-1), leading to an energy-dependent ^3He : ^4He ratio. These observations point to unique and distinct properties of ^3He in these events and place new constraints on models that seek to explain enhancements of ^3He and heavy ions using the same mechanisms. In addition to the events with spectra in the form of power laws or double power laws, there is a second class of event in which the low-energy ^3He and Fe spectra are rounded, while the ^4He remains a power law. In these cases ^3He and Fe spectra can be fitted at low energies by a stochastic acceleration model, but this model does not explain the higher energy portions of these spectra, nor the power-law spectral forms of the ^4He. These observations appear to require an additional mechanism, such as acceleration by cascading MHD turbulence. The ^3He enrichment pattern that we observe suggests that all these different spectral features might be due to processes with a common origin but then followed by different acceleration histories.",
"doi": "10.1086/341112",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2002-08-01",
"series_number": "2",
"volume": "574",
"issue": "2",
"pages": "1039-1058"
},
{
"id": "authors:817w6-4ew86",
"collection": "authors",
"collection_id": "817w6-4ew86",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-110121697",
"type": "article",
"title": "Fractionation of solar energetic particles and solar wind according to first ionization potential",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "Although it is well known that solar energetic particles are depleted in elements with first ionization potential (FIP) greater than \u223c10 eV, it is less well known that the degree of FIP fractionation varies from event to event. Similar fractionation patterns and variations are observed in the solar wind, suggesting that these variations may have a common origin. We review evidence for the FIP-related fractionation of SEPs and compare it with FIP fractionation effects in the solar wind at 1 AU. On the basis of several significant differences between the solar wind and SEP compositions, we suggest that most solar energetic particles are not simply an accelerated sample of the average solar wind as observed at 1 AU; rather, solar particles and fast and slow solar wind appear to be distinct samples of coronal material with distinctly different FIP-fractionation patterns.",
"doi": "10.1016/S0273-1177(02)00263-6",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2002",
"series_number": "1",
"volume": "30",
"issue": "1",
"pages": "79-84"
},
{
"id": "authors:8xpt8-xbe36",
"collection": "authors",
"collection_id": "8xpt8-xbe36",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-134134744",
"type": "article",
"title": "Energetic particle composition at 1 au during periods of moderate interplanetary particle fluxes",
"author": [
{
"family_name": "Slocum",
"given_name": "P. L.",
"clpid": "Slocum-P-L"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "It has recently been proposed that residual energetic ions from preceding impulsive solar energetic particle (SEP) events may contribute to the source population for the larger gradual events accelerated by CME-driven shocks (Mason et al., 1999). This suggests that there may be impulsive SEP material left in interplanetary space during periods relatively free of energetic particle activity. To test this idea we have studied the heavy ions and ^3He present at L1 during periods of low\u2014to\u2014moderate energetic particle fluxes between February 1998 and April 2000. Using the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have measured the energy spectra of heavy elements (Z\u22656) and ^3He over the ranges \u223c8\u201320 MeV/nucleon and \u223c4\u201315 MeV/nucleon, respectively. In these energy spectra, we have looked for spectral and compositional signatures typically characteristic of impulsive or gradual SEP events. We discuss the implications of these observations for the origin of particles accelerated in gradual SEP events.",
"doi": "10.1016/S0273-1177(02)00264-8",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2002",
"series_number": "1",
"volume": "30",
"issue": "1",
"pages": "97-104"
},
{
"id": "authors:85bh6-bkx41",
"collection": "authors",
"collection_id": "85bh6-bkx41",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-082013151",
"type": "article",
"title": "Measurement of the Secondary Radionuclides ^(10)Be, ^(26)Al, ^(36)Cl, ^(54)Mn, and ^(14)C and Implications for the Galactic Cosmic-Ray Age",
"author": [
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
}
],
"abstract": "We report on abundance measurements of ^(10)Be, ^(26)Al, ^(36)Cl, and ^(54)Mn in the Galactic cosmic rays (GCRs) using the Cosmic-Ray Isotope Spectrometer (CRIS) instrument aboard the Advanced Composition Explorer spacecraft at energies from ~70 to ~400 MeV nucleon^(-1). We also report an upper limit on the abundance of GCR ^(14)C. The high statistical significance of these measurements allows the energy dependence of their relative abundances to be studied. A steady-state, leaky-box propagation model, incorporating observations of the local interstellar medium (ISM) composition and density and recent partial fragmentation cross section measurements, is used to interpret these abundances. Using this model, the individual galactic confinement times derived using data for each species are consistent with a unique confinement time value of \u03c4_(esc) = 15.0 \u00b1 1.6 Myr. The CRIS abundance measurements are consistent with propagation through an average ISM hydrogen number density n_H = 0.34 \u00b1 0.04 H atoms cm^(-3). The surviving fractions, f, for each radioactive species have been calculated. From predictions of the diffusion models of Ptuskin & Soutoul, the values of f indicate an interstellar cosmic-ray diffusion coefficient of D = (3.5 \u00b1 2.0) \u00d7 10^(28) cm^2 s^(-1).",
"doi": "10.1086/323842",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2001-12-20",
"series_number": "2",
"volume": "563",
"issue": "2",
"pages": "768-792"
},
{
"id": "authors:0crfh-4w440",
"collection": "authors",
"collection_id": "0crfh-4w440",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-110736601",
"type": "article",
"title": "Solar minimum spectra of galactic cosmic rays and their implications for models of the near-Earth radiation environment",
"author": [
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
}
],
"abstract": "The radiation dose from galactic cosmic rays during a manned mission to Mars is expected to be comparable to the allowable limit for space shuttle astronauts. Most of this dose would be due to galactic cosmic rays with energies < 1 GeV nucleon^(\u22121), with important contributions from heavy nuclei in spite of their low abundance relative to H and He. Using instruments on NASA's Advanced Composition Explorer (ACE) spacecraft, we have made the most statistically precise measurements to date of the solar minimum energy spectra of cosmic ray nuclei with charge Z = 4\u201328 in the energy range \u223c 40\u2013500 MeV nucleon^(\u22121). We compare these measurements obtained during the 1997\u20131998 solar minimum period with measurements from previous solar minima and with models of the near-Earth radiation environment currently used to perform shielding and dose calculations. We find that the cosmic ray heavy-element spectra measured by ACE are as much as 20% higher than previously published solar minimum measurements. We also find significant differences between the ACE measurements and the predictions of available models of the near-Earth radiation environment, suggesting that these models need revision. We describe a cosmic ray interstellar propagation and solar modulation model that provides an improved fit to the ACE measurements compared to radiation environment models currently in use.",
"doi": "10.1029/2000JA000325",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2001-12-01",
"series_number": "A12",
"volume": "106",
"issue": "A12",
"pages": "29979-29987"
},
{
"id": "authors:babjv-nnp37",
"collection": "authors",
"collection_id": "babjv-nnp37",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-085913469",
"type": "article",
"title": "Forecasting the arrival of shock-accelerated solar energetic particles at Earth",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Slocum",
"given_name": "P. L.",
"clpid": "Slocum-P-L"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Energetic particles accelerated at interplanetary shocks can result in an increased radiation dose for astronauts as well as an increased risk to satellite hardware. These shocks are known to occasionally accelerate protons to energies greater than 100 MeV and can result in very high fluxes. Advanced warning of the arrival of strong interplanetary shocks can enable steps to be taken to minimize the potential risks. In an effort to monitor and assess the radiation risk to astronauts, two real-time count rate monitors were implemented in the Solar Isotope Spectrometer (SIS) on the ACE spacecraft. These rates measure protons with energies >10 and >30 MeV. Since ACE is located at the L1 Lagrangian point, these rates provide information and warning up to 1 hour before an interplanetary shock reaches Earth. Using ACE and GOES, data we have examined examples of shocks and associated energetic particles that have been detected at ACE and were later observed near Earth in an effort to develop more fully the forecasting capability of ACE. Because of the limited amount of solar activity during 1997\u20131999, this current work is primarily a proof of concept.",
"doi": "10.1029/2000JA000216",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "2001-10-01",
"series_number": "A10",
"volume": "106",
"issue": "A10",
"pages": "20979-20983"
},
{
"id": "authors:x4yd0-9e422",
"collection": "authors",
"collection_id": "x4yd0-9e422",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-090214937",
"type": "article",
"title": "The Origin of Primary Cosmic Rays: Constraints from ACE Elemental and Isotopic Composition Observations",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Lijowski",
"given_name": "M.",
"clpid": "Lijowski-M-L"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Cosmic-ray isotope observations from NASA's Advanced Composition Explorer (ACE) mission have been used to investigate the composition of cosmic-ray source material. Source abundances relative to ^(56)Fe are reported for eleven isotopes of Ca, Fe, Co, and Ni, including the very rare isotopes ^(48)Ca and ^(64)Ni. Although the source abundances range over a factor \u223c10^4, most of the ratios to ^(56)Fe are consistent with solar-system values to within \u223c20%. However, there are some notable differences, the most significant being an excess of \u223c(70\u00b130)% relative to the solar system for the cosmic-ray source ratio ^(58)Fe/^(56)Fe. The possible association of such an excess with a contribution to the cosmic-ray source from Wolf\u2013Rayet star ejecta is discussed.",
"doi": "10.1023/A:1013816209004",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2001-10",
"series_number": "1-4",
"volume": "99",
"issue": "1-4",
"pages": "15-26"
},
{
"id": "authors:btrqg-5hc77",
"collection": "authors",
"collection_id": "btrqg-5hc77",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-154628633",
"type": "article",
"title": "Radioactive clocks and cosmic-ray transport in the galaxy",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Niebur",
"given_name": "S. M.",
"clpid": "Niebur-S-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "There are a number of radioactive 'clocks' in the cosmic radiation that can be used to measure the time scales for cosmic ray processes in the Galaxy. With high-resolution isotope measurements available from ACE it is now possible to read these clocks with greatly improved accuracy and address key questions about the origin and lifetime of cosmic rays. This paper discusses the status of three such investigations.",
"doi": "10.1023/A:1013868225842",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "2001-10",
"series_number": "1-4",
"volume": "99",
"issue": "1-4",
"pages": "27-39"
},
{
"id": "authors:0x5zr-b1w10",
"collection": "authors",
"collection_id": "0x5zr-b1w10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-133307053",
"type": "article",
"title": "Galactic cosmic ray neon isotopic abundances measured by the cosmic ray isotope spectrometer (CRIS) on ACE",
"author": [
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Klarmann",
"given_name": "J.",
"clpid": "Klarmann-J"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Lijowski",
"given_name": "M.",
"clpid": "Lijowski-M"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "We present measurements of neon isotopic abundances from the ACE-CRIS experiment. These abundances have been obtained in seven energy intervals over the energy range of \u223c80\u2264E\u2264280 MeV/nucleon. We find that the ^(22)Ne/^(20)Ne abundance ratio at the cosmic-ray source is a factor of 5.0\u00b10.2 greater than for the solar wind. These measured abundances agree well with previous experiments. The significance of these results is discussed.",
"doi": "10.1016/S0273-1177(01)00119-3",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2001",
"series_number": "4",
"volume": "27",
"issue": "4",
"pages": "767-772"
},
{
"id": "authors:4qa5f-kw436",
"collection": "authors",
"collection_id": "4qa5f-kw436",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-115932195",
"type": "article",
"title": "Cosmic-ray time scales using radioactive clocks",
"author": [
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Lijowski",
"given_name": "M.",
"clpid": "Lijowski-M"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Radionuclides in the galactic cosmic rays serve as chronometers for measuring the characteristic time of physical processes affecting cosmic ray energy spectra and composition. The radionuclide ^(59)Ni, present in the ejecta of supernovae, will decay to ^(59)Co via electron-capture with a halflife of T_(1/2) = 7.6 \u00d7 10^4 yr. However, if the cosmic ray acceleration time scale is shorter than the decay halflife, ^(59)Ni will become fully-stripped of electrons and will be present in the cosmic rays. Abundances of cosmic ray ^(59)Ni and ^(59)Co measured with the Cosmic Ray Isotope Spectrometer (CRIS) are consistent with the decay of all source ^(59)Ni, implying an acceleration time delay > 10^5 yr. Abundances of the \u03b2-decay radioactive secondaries, produced by fragmentation of the cosmic rays during transport in the interstellar medium (ISM), depend on the time scales for spallation and escape from the Galaxy. Consequently, measurement of these abundances can be used to derive the galactic confinement time, \u03c4_(esc), for cosmic rays. Using the abundances of the \u03b2-decay species ^(10)Be, ^(26)Al, ^(36)Cl, and ^(54)Mn measured by CRIS, we find a confinement time \u03c4_(esc) \u223c 15 Myr.",
"doi": "10.1016/S0273-1177(01)00114-4",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2001",
"series_number": "4",
"volume": "27",
"issue": "4",
"pages": "727-736"
},
{
"id": "authors:rrt4w-xvp29",
"collection": "authors",
"collection_id": "rrt4w-xvp29",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-132540360",
"type": "article",
"title": "Distinguishing galactic cosmic-ray source models with first ionization potential and volatility",
"author": [
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Barghouty",
"given_name": "A. F.",
"clpid": "Barghouty-A-F"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "Studies of the galactic cosmic-ray source composition reveal a pattern in the elemental abundances that may be controlled by the first ionization potential (FIP) or a closely correlated parameter, the condensation temperature (volatility). Determining the true parameter is key identifying the galactic cosmic-ray source (GCRS) material. Using data from the CRIS instrument onboard the ACE spacecraft, we examine five elements that are more volatile than other elements of similar FIP. Three of these (Na, Cu, Ge) show small deficits in their source abundances that may suggest a volatility-dependent fractionation. The source abundances of Ga and Zn (an intermediate FIP element) are consistent with either model. Possible systematic uncertainties from the cosmic-ray pathlength estimate as well as effects due to the instrumental acceptance are discussed. We also compare the GCRS composition to that observed in solar energetic particles.",
"doi": "10.1016/S0273-1177(01)00116-8",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2001",
"series_number": "4",
"volume": "27",
"issue": "4",
"pages": "779-784"
},
{
"id": "authors:7m8rw-9bf22",
"collection": "authors",
"collection_id": "7m8rw-9bf22",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140826-112434005",
"type": "article",
"title": "The isotopic source composition of cosmic-ray iron, cobalt, and nickel",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Davis",
"given_name": "A. J.",
"clpid": "Davis-A-J"
},
{
"family_name": "George",
"given_name": "J. S.",
"clpid": "George-J-S"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Israel",
"given_name": "M. H.",
"orcid": "0000-0002-8104-208X",
"clpid": "Israel-M-H"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Lijowski",
"given_name": "M.",
"clpid": "Lijowski-M"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "The isotopic composition of cosmic-ray Fe, Co, and Ni at energies \u223c150\u2013500 MeV/nucleon has been measured with the Cosmic-Ray Isotope Spectrometer (CRIS) instrument on ACE. Source abundances have been derived from a leaky-box propagation model using secondary species in the range 41 \u2264 A \u2264 55 to constrain the calculated secondary contributions to the Fe, Co, and Ni isotopes. The derived relative source abundances bear a strong resemblance to solar-system values. The most significant difference, an excess of \u223c (70 \u00b1 30)%, is found for the source abundance ratio ^(58)Fe/^(56)Fe. Some implications of the derived source composition for the origin of cosmic rays are discussed.",
"doi": "10.1016/S0273-1177(01)00120-X",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "2001",
"series_number": "4",
"volume": "27",
"issue": "4",
"pages": "773-778"
},
{
"id": "authors:6vs9s-dcp02",
"collection": "authors",
"collection_id": "6vs9s-dcp02",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140225-104036311",
"type": "article",
"title": "Solar cycle dependence of the geomagnetically trapped anomalous cosmic rays",
"author": [
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
}
],
"abstract": "Solar cycle variations in the intensity of geomagnetically trapped anomalous cosmic ray (ACR) oxygen are demonstrated by \u223c7 years of data from the SAMPEX satellite. They correspond to similar variations in the interplanetary ACR source. Trapped particle losses during the approach to solar maximum are not associated with geomagnetic activity and may be consistent with atmospheric energy degradation. The average trapped particle pitch angle distribution and energy spectra support this interpretation in which both source and loss rates are proportional to atmospheric density.",
"doi": "10.1029/2000GL000049",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "2000-08-01",
"series_number": "15",
"volume": "27",
"issue": "15",
"pages": "2349-2352"
},
{
"id": "authors:0eewn-xz288",
"collection": "authors",
"collection_id": "0eewn-xz288",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:ABUprl00",
"type": "article",
"title": "Exclusion limits on the WIMP-nucleon cross section from the Cryogenic Dark Matter Search",
"author": [
{
"family_name": "Abusaidi",
"given_name": "R.",
"clpid": "Abusaidi-R"
},
{
"family_name": "Akerib",
"given_name": "D. S.",
"clpid": "Akerib-D-S"
},
{
"family_name": "Barnes",
"given_name": "P. D., Jr.",
"clpid": "Barnes-P-D-Jr"
},
{
"family_name": "Bauer",
"given_name": "D. A.",
"clpid": "Bauer-D-A"
},
{
"family_name": "Bolozdynya",
"given_name": "A.",
"clpid": "Bolozdynya-A"
},
{
"family_name": "Brink",
"given_name": "P. L.",
"clpid": "Brink-P-L"
},
{
"family_name": "Bunker",
"given_name": "R.",
"clpid": "Bunker-R"
},
{
"family_name": "Cabrera",
"given_name": "B.",
"clpid": "Cabrera-B"
},
{
"family_name": "Caldwell",
"given_name": "D. O.",
"clpid": "Caldwell-D-O"
},
{
"family_name": "Castle",
"given_name": "J. P.",
"clpid": "Castle-J-P"
},
{
"family_name": "Clarke",
"given_name": "R. M.",
"clpid": "Clarke-R-M"
},
{
"family_name": "Colling",
"given_name": "P.",
"clpid": "Colling-P"
},
{
"family_name": "Crisler",
"given_name": "M. B.",
"clpid": "Crisler-M-B"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Da Silva",
"given_name": "A.",
"clpid": "Da-Silva-A"
},
{
"family_name": "Davies",
"given_name": "A. K.",
"clpid": "Davies-A-K"
},
{
"family_name": "Dixon",
"given_name": "R.",
"clpid": "Dixon-R"
},
{
"family_name": "Dougherty",
"given_name": "B. L.",
"clpid": "Dougherty-B-L"
},
{
"family_name": "Driscoll",
"given_name": "D.",
"clpid": "Driscoll-D"
},
{
"family_name": "Eichblatt",
"given_name": "S.",
"clpid": "Eichblatt-S"
},
{
"family_name": "Emes",
"given_name": "J.",
"clpid": "Emes-J"
},
{
"family_name": "Gaitskell",
"given_name": "R. J.",
"clpid": "Gaitskell-R-J"
},
{
"family_name": "Golwala",
"given_name": "S. R.",
"orcid": "0000-0002-1098-7174",
"clpid": "Golwala-S-R"
},
{
"family_name": "Hale",
"given_name": "D.",
"clpid": "Hale-D"
},
{
"family_name": "Haller",
"given_name": "E. E.",
"clpid": "Haller-E-E"
},
{
"family_name": "Hellmig",
"given_name": "J.",
"clpid": "Hellmig-J"
},
{
"family_name": "Huber",
"given_name": "M. E.",
"clpid": "Huber-M-E"
},
{
"family_name": "Irwin",
"given_name": "K. D.",
"clpid": "Irwin-K-D"
},
{
"family_name": "Jochum",
"given_name": "J.",
"clpid": "Jochum-J"
},
{
"family_name": "Lipschultz",
"given_name": "F. P.",
"clpid": "Lipschultz-F-P"
},
{
"family_name": "Lu",
"given_name": "A.",
"clpid": "Lu-A"
},
{
"family_name": "Mandic",
"given_name": "V.",
"clpid": "Mandic-V"
},
{
"family_name": "Martinis",
"given_name": "J. M.",
"clpid": "Martinis-J-M"
},
{
"family_name": "Nam",
"given_name": "S. W.",
"clpid": "Nam-S-W"
},
{
"family_name": "Nelson",
"given_name": "H.",
"clpid": "Nelson-H"
},
{
"family_name": "Neuhauser",
"given_name": "B.",
"clpid": "Neuhauser-B"
},
{
"family_name": "Penn",
"given_name": "M. J.",
"clpid": "Penn-M-J"
},
{
"family_name": "Perera",
"given_name": "T. A.",
"clpid": "Perera-T-A"
},
{
"family_name": "Isaac",
"given_name": "M. C. Perillo",
"clpid": "Isaac-M-C-P"
},
{
"family_name": "Pritychenko",
"given_name": "B.",
"clpid": "Pritychenko-B"
},
{
"family_name": "Ross",
"given_name": "R. R.",
"clpid": "Ross-R-R"
},
{
"family_name": "Saab",
"given_name": "T.",
"clpid": "Saab-T"
},
{
"family_name": "Sadoulet",
"given_name": "B.",
"clpid": "Sadoulet-B"
},
{
"family_name": "Schnee",
"given_name": "R. W.",
"clpid": "Schnee-R-W"
},
{
"family_name": "Seitz",
"given_name": "D. N.",
"clpid": "Seitz-D-N"
},
{
"family_name": "Shestople",
"given_name": "P.",
"clpid": "Shestople-P"
},
{
"family_name": "Shutt",
"given_name": "T.",
"clpid": "Shutt-T"
},
{
"family_name": "Smith",
"given_name": "A.",
"orcid": "0000-0002-1938-4660",
"clpid": "Smith-A"
},
{
"family_name": "Smith",
"given_name": "G. W.",
"clpid": "Smith-G-W"
},
{
"family_name": "Sonnenschein",
"given_name": "A. H.",
"clpid": "Sonnenschein-A-H"
},
{
"family_name": "Spadafora",
"given_name": "A. L.",
"clpid": "Spadafora-A-L"
},
{
"family_name": "Stockwell",
"given_name": "W.",
"clpid": "Stockwell-W"
},
{
"family_name": "Taylor",
"given_name": "J. D.",
"clpid": "Taylor-J-D"
},
{
"family_name": "White",
"given_name": "S.",
"clpid": "White-S"
},
{
"family_name": "Yellin",
"given_name": "S.",
"clpid": "Yellin-S"
},
{
"family_name": "Young",
"given_name": "B. A.",
"clpid": "Young-B-A"
},
{
"literal": "CDMS Collaboration"
}
],
"abstract": "The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c^2 WIMP mass and, at >75% C.L., the entire 3\u03c3 allowed region for the WIMP signal reported by the DAMA experiment.",
"doi": "10.1103/PhysRevLett.84.5699",
"issn": "0031-9007",
"publisher": "American Physical Society",
"publication": "Physical Review Letters",
"publication_date": "2000-06-19",
"series_number": "25",
"volume": "84",
"issue": "25",
"pages": "5699-5703"
},
{
"id": "authors:z2k7x-f9s78",
"collection": "authors",
"collection_id": "z2k7x-f9s78",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140902-132158815",
"type": "article",
"title": "Constraints on the Time Delay between Nucleosynthesis and Cosmic-Ray Acceleration from Observations of ^(59)Ni and ^(59)Co",
"author": [
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Dougherty",
"given_name": "B. L.",
"clpid": "Dougherty-B-L"
},
{
"family_name": "Hink",
"given_name": "P. L.",
"clpid": "Hink-P-L"
},
{
"family_name": "Klarmann",
"given_name": "J.",
"clpid": "Klarmann-J"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Lijowski",
"given_name": "M.",
"clpid": "Lijowski-M"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Thayer",
"given_name": "M. R.",
"clpid": "Thayer-M-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Yanasak",
"given_name": "N. E.",
"clpid": "Yanasak-N-E"
}
],
"abstract": "Measurements of the abundances of cosmic-ray ^(59)Ni and ^(59)Co are reported from the Cosmic-Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer. These nuclides form a parent-daughter pair in a radioactive decay which can occur only by electron capture. This decay cannot occur once the nuclei are accelerated to high energies and stripped of their electrons. The CRIS data indicate that the decay of ^(59)Ni to ^(59)Co has occurred, leading to the conclusion that a time longer than the 7.6 \u00d7 10^4 yr half-life of ^(59)Ni elapsed before the particles were accelerated. Such long delays indicate the acceleration of old, stellar or interstellar material rather than fresh supernova ejecta. For cosmic-ray source material to have the composition of supernova ejecta would require that these ejecta not undergo significant mixing with normal interstellar gas before ~10^5 yr has elapsed.",
"doi": "10.1086/312242",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "1999-09-20",
"series_number": "1",
"volume": "523",
"issue": "1",
"pages": "L61-L64"
},
{
"id": "authors:taehd-0mp12",
"collection": "authors",
"collection_id": "taehd-0mp12",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-151845333",
"type": "article",
"title": "New observations of heavy-ion-rich solar particle events from ACE",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Following launch of the Advanced Composition Explorer in August 1997, the Solar Isotope Spectrometer measured the composition of nine solar energetic particle events. We have used isotopic measurements of Ne to determine the degree of charge-to-mass-dependent fractionation and infer the charge states of C-Ni in the four most heavy-ion-rich of the nine events. The results indicate a source temperature of \u223c4\u00d710^6 K; this and the measured abundances suggest that these four events are more characteristic of impulsive events than gradual. Although the ^3He/^4He ratios are not enhanced to the level commonly ascribed to impulsive events, there are sizable enhancements over typical solar wind values measured in three of the events.",
"doi": "10.1029/1999GL900560",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1999-09-01",
"series_number": "17",
"volume": "26",
"issue": "17",
"pages": "2697-2700"
},
{
"id": "authors:77c1s-a3b69",
"collection": "authors",
"collection_id": "77c1s-a3b69",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140828-090809602",
"type": "article",
"title": "Event-to-event variations in the isotopic composition of neon in solar energetic particle events",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Using the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have measured the isotopic composition of neon at 24\u201372 MeV/nucleon in nine solar energetic particle events between 4 November 1997 and 16 November 1998. The ^(22)Ne/^(20)Ne ratio varies from \u223c0.7 to \u223c2 times the solar wind value from event to event, indicating significant mass fractionation in the acceleration and/or transport of these particles. The mass fractionation is strongly correlated with the Fe/O and Na/Mg element abundance ratios, suggesting that elemental and isotopic fractionation are both governed by the ionic charge to mass ratio.",
"doi": "10.1029/1999GL900561",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1999-09-01",
"series_number": "17",
"volume": "26",
"issue": "17",
"pages": "2693-2696"
},
{
"id": "authors:knhg2-9x340",
"collection": "authors",
"collection_id": "knhg2-9x340",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-113048212",
"type": "article",
"title": "Unusual isotopic composition of solar energetic particles observed in the November 6, 1997 event",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Dougherty",
"given_name": "B. L.",
"clpid": "Dougherty-B-L"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Using the Solar Isotope Spectrometer on the Advanced Composition Explorer, we have measured the isotopic composition of solar energetic particles (SEPs) with energies of tens of MeV/nucleon during the November 6, 1997 solar event, including isotopes never before reported in SEPs, such as ^(34)S, ^(38)Ar, ^(44)Ca, ^(54)Fe, and ^(60)Ni, as well as isotopes of C, N, O, Ne, Mg, and Si. Abundances are found to be enhanced by factors of \u223c2 relative to the standard solar system values for ^(22)Ne/^(20)Ne and ^(26)Mg/^(24)Mg. Overall, the enrichments of the isotope ratios show a correlation with the ratio of masses, M_2/M_1, scaling approximately as (M_2/M_1)^7, although significant deviations from this trend are evident.",
"doi": "10.1029/1998GL900173",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1999-01-15",
"series_number": "2",
"volume": "26",
"issue": "2",
"pages": "153-156"
},
{
"id": "authors:z1hce-b0m16",
"collection": "authors",
"collection_id": "z1hce-b0m16",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-114427003",
"type": "article",
"title": "Inferred charge states of high energy solar particles from the Solar Isotope Spectrometer on ACE",
"author": [
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Dougherty",
"given_name": "B. L.",
"clpid": "Dougherty-B-L"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The large solar event on November 6, 1997, was enriched in heavy elements (Fe/O \u223c 1) with very hard energy spectra (power law index of \u22122). There was also a large enrichment in heavier isotopes, suggesting unusually strong charge to mass (Q/M) fractionation (\u223c(Q/M)^(\u22127)). Assuming that the fractionation is dominated by Q/M and first ionization potential (FIP) related processes, we have inferred the charge states of twelve elements with energies of 12\u201360 MeV/nucleon. These results suggest a source temperature of 3\u20136 \u00d7 10^6K, significantly higher than deduced at lower energies.",
"doi": "10.1029/1998GL900218",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1999-01-15",
"series_number": "2",
"volume": "26",
"issue": "2",
"pages": "149-152"
},
{
"id": "authors:k0xp3-78g73",
"collection": "authors",
"collection_id": "k0xp3-78g73",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140827-130259341",
"type": "article",
"title": "Particle acceleration and sources in the November 1997 solar energetic particle events",
"author": [
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Dwyer",
"given_name": "J. R.",
"clpid": "Dwyer-J-R"
},
{
"family_name": "Gold",
"given_name": "R. E.",
"clpid": "Gold-R-E"
},
{
"family_name": "Krimigis",
"given_name": "S. M.",
"orcid": "0000-0003-2781-2386",
"clpid": "Krimigis-S-M"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "M\u00f6bius",
"given_name": "E.",
"clpid": "M\u00f6bius-E"
},
{
"family_name": "Popecki",
"given_name": "M.",
"clpid": "Popecki-M"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
}
],
"abstract": "We report studies of two large solar energetic particle (SEP) events on Nov. 4 and 6, 1997 that were observed using advanced energetic particle detectors on the ACE and the Wind spacecraft. Both events showed enriched Fe/O, and had a \u223c1 MeV/n ^3He/^4He ratio = 2.1 \u00d7 10^(\u22123), 4 times the coronal value. The Nov. 6 event had exceptionally hard spectra, with much higher intensities of high energy (10s of MeV) particles than the Nov. 4 event, yet below 1 MeV/n the intensities in the Nov. 6 event were lower than for Nov. 4. Strong, complex temporal variations observed for \u223c120 keV Fe/O contrasted with only gradual changes of this ratio at \u223c25 MeV/n. A spectral break was observed in the Nov. 6 event, wherein below a few MeV/n the spectra became harder. Taken together, these observations point to different seed and acceleration mechanisms dominating at low and high energies in these events.",
"doi": "10.1029/1998GL900235",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1999-01-15",
"series_number": "2",
"volume": "26",
"issue": "2",
"pages": "141-144"
},
{
"id": "authors:dk81c-bt866",
"collection": "authors",
"collection_id": "dk81c-bt866",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140226-111247648",
"type": "article",
"title": "Anomalous cosmic rays: Observations",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The latitudinal gradients of galactic cosmic ray protons and anomalous cosmic ray (ACR) helium appear to be symmetrical about a plane displaced \u223c10\u00b0 south of the heliographic equator, similar to the displacement of the heliospheric current sheet (HCS). The radial gradient of \u223c10 MeV/nuc ACR oxygen in the outer heliosphere is correlated with the amplitude of the tilt of the HCS. The form of the correlation depends on the magnetic polarity of the solar cycle. The observed radial gradients are the basis for an empirical model that reasonably describes the modulation of \u223c2\u20133 GV ACR oxygen at low heliographic latitudes over a 25-year period.",
"doi": "10.1016/S0273-1177(99)80005-2",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "1999",
"series_number": "3",
"volume": "23",
"issue": "3",
"pages": "509-520"
},
{
"id": "authors:ynxp5-kej13",
"collection": "authors",
"collection_id": "ynxp5-kej13",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131031-083104716",
"type": "article",
"title": "The Cosmic-Ray Isotope Spectrometer for the Advanced Composition Explorer",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Gauld",
"given_name": "B.",
"clpid": "Gauld-B"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Thayer",
"given_name": "M. R.",
"clpid": "Thayer-M-R"
}
],
"abstract": "The Cosmic-Ray Isotope Spectrometer is designed to cover the highest decade of the Advanced Composition Explorer's energy interval, from \u223c50 to \u223c500 MeV nucl^(\u22121), with isotopic resolution for elements from Z\u22432 to Z\u224330. The nuclei detected in this energy interval are predominantly cosmic rays originating in our Galaxy. This sample of galactic matter can be used to investigate the nucleosynthesis of the parent material, as well as fractionation, acceleration, and transport processes that these particles undergo in the Galaxy and in the interplanetary medium.\nCharge and mass identification with CRIS is based on multiple measurements of dE/dx and total energy in stacks of silicon detectors, and trajectory measurements in a scintillating optical fiber trajectory (SOFT) hodoscope. The instrument has a geometrical factor of \u223cr250 cm^2 sr for isotope measurements, and should accumulate \u223c5\u00d710^6 stopping heavy nuclei (Z>2) in two years of data collection under solar minimum conditions.",
"doi": "10.1023/A:1005075813033",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1998-07",
"series_number": "1-4",
"volume": "86",
"issue": "1-4",
"pages": "285-356"
},
{
"id": "authors:ntx1g-crn67",
"collection": "authors",
"collection_id": "ntx1g-crn67",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140908-101152277",
"type": "article",
"title": "Anomalous cosmic rays and solar modulation",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We review aspects of anomalous cosmic rays (ACRs) that bear on the solar modulation of energetic particles in the heliosphere. We show that the latitudinal and radial gradients of these particles exhibit a 22-year periodicity in concert with the reversal of the Sun's magnetic field. The power-law index of the low energy portion of the energy spectrum of ACRs at the shock in 1996 appears to be \u2264 -1.3, suggesting that the strength of the solar wind termination shock at the helioequatorial plane is relatively weak, with s \u2264 2.8. The rigidity dependence of the perpendicular interplanetary mean free path in the outer heliosphere for particles with rigidities between \u223c 0.2 and 0.7 GV varies approximately as R^2, where R is particle rigidity. There is evidence that ACR oxygen is primarily multiply charged above \u223c 20 MeV/nuc and primarily singly-charged below \u223c 16 MeV/nuc. The location of the termination shock was at \u223c 65 AU in 1987 and \u223c 85 AU in 1994.",
"doi": "10.1023/A:1005027929871",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1998-01",
"series_number": "1-2",
"volume": "83",
"issue": "1-2",
"pages": "357-408"
},
{
"id": "authors:9hyf7-f8e28",
"collection": "authors",
"collection_id": "9hyf7-f8e28",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20160406-113935658",
"type": "article",
"title": "Global Processes that Determine Cosmic Ray Modulation",
"author": [
{
"family_name": "Fisk",
"given_name": "L. A.",
"clpid": "Fisk-L-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The global processes that determine cosmic ray modulation are reviewed. The essential elements of the theory which describes cosmic ray behavior in the heliosphere are summarized, and a series of discussions is presented which compare the expectations of this theory with observations of the spatial and temporal behavior of both galactic cosmic rays and the anomalous component; the behavior of cosmic ray electrons and ions; and the 26-day variations in cosmic rays as a function of heliographic latitude. The general conclusion is that the current theory is essentially correct. There is clear evidence, in solar minimum conditions, that the cosmic rays and the anomalous component behave as is expected from theory, with strong effects of gradient and curvature drifts. There is strong evidence of considerable latitude transport of the cosmic rays, at all energies, but the mechanism by which this occurs is unclear. Despite the apparent success of the theory, there is no single choice for the parameters which describe cosmic ray behavior, which can account for all of the observed temporal and spatial variations, spectra, and electron vs. ion behavior.",
"doi": "10.1023/A:1005074923940",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1998-01",
"series_number": "1-2",
"volume": "83",
"issue": "1-2",
"pages": "179-214"
},
{
"id": "authors:a7edy-g7851",
"collection": "authors",
"collection_id": "a7edy-g7851",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140908-101236271",
"type": "article",
"title": "The solar isotope spectrometer for the Advanced Composition Explorer",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cohen",
"given_name": "C. M. S.",
"orcid": "0000-0002-0978-8127",
"clpid": "Cohen-C-M-S"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Gauld",
"given_name": "B.",
"clpid": "Gauld-B"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Thayer",
"given_name": "M. R.",
"clpid": "Thayer-M-R"
},
{
"family_name": "Dougherty",
"given_name": "B. L.",
"clpid": "Dougherty-B-L"
},
{
"family_name": "Grumm",
"given_name": "R. L.",
"clpid": "Grumm-R-L"
},
{
"family_name": "Milliken",
"given_name": "B. D.",
"clpid": "Milliken-B-D"
},
{
"family_name": "Radocinski",
"given_name": "R. G.",
"clpid": "Radocinski-R-G"
},
{
"family_name": "Wiedenbeck",
"given_name": "M. E.",
"orcid": "0000-0002-2825-3128",
"clpid": "Wiedenbeck-M-E"
},
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Shuman",
"given_name": "S.",
"clpid": "Shuman-S"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The Solar Isotope Spectrometer (SIS), one of nine instruments on the Advanced Composition Explorer (ACE), is designed to provide high- resolution measurements of the isotopic composition of energetic nuclei from He to Zn (Z=2 to 30) over the energy range from \u223c10 to \u223c100 MeV nucl^(\u22121). During large solar events SIS will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona and to study particle acceleration processes. During solar quiet times SIS will measure the isotopes of low-energy cosmic rays from the Galaxy and isotopes of the anomalous cosmic-ray component, which originates in the nearby interstellar medium. SIS has two telescopes composed of silicon solid-state detectors that provide measurements of the nuclear charge, mass, and kinetic energy of incident nuclei. Within each telescope, particle trajectories are measured with a pair of two-dimensional silicon-strip detectors instrumented with custom, very large-scale integrated (VLSI) electronics to provide both position and energy-loss measurements. SIS was especially designed to achieve excellent mass resolution under the extreme, high flux conditions encountered in large solar particle events. It provides a geometry factor of \u223c40 cm^2 sr, significantly greater than earlier solar particle isotope spectrometers. A microprocessor controls the instrument operation, sorts events into prioritized buffers on the basis of their charge, range, angle of incidence, and quality of trajectory determination, and formats data for readout by the spacecraft. This paper describes the design and operation of SIS and the scientific objectives that the instrument will address.",
"doi": "10.1023/A:1005027929871",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1998",
"series_number": "1-4",
"volume": "86",
"issue": "1-4",
"pages": "357-408"
},
{
"id": "authors:aa4f1-18547",
"collection": "authors",
"collection_id": "aa4f1-18547",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150108-163318431",
"type": "article",
"title": "Anomalous Cosmic Ray Data Sets",
"author": [
{
"family_name": "Marsden",
"given_name": "R. G.",
"clpid": "Marsden-R-G"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Klecker",
"given_name": "B.",
"clpid": "Klecker-B"
},
{
"family_name": "Lanzerotti",
"given_name": "L. J.",
"clpid": "Lanzerotti-L-J"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "McKibben",
"given_name": "R. B.",
"clpid": "McKibben-R-B"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Trattner",
"given_name": "K. J.",
"clpid": "Trattner-K-J"
}
],
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1998",
"pages": "263-269"
},
{
"id": "authors:3n9dw-xvh63",
"collection": "authors",
"collection_id": "3n9dw-xvh63",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140703-215730302",
"type": "article",
"title": "The Isotopic Composition of Anomalous Cosmic Rays from SAMPEX",
"author": [
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Measurements of the anomalous cosmic ray (ACR) isotopic composition have been made in three regions of the magnetosphere accessible from the polar Earth orbit of SAMPEX, including the interplanetary medium at high latitudes and geomagnetically trapped ACRs. At those latitudes where ACRs can penetrate the Earth's magnetic field while fully stripped galactic cosmic rays (GCRs) of similar energies are excluded, a pure ACR sample is observed to have the following composition: ^(15)N/N < 0.023, ^(18)O/^(16)O < 0.0034, and ^(22)Ne/^(20)Ne = 0.077(+0.085, -0.023). We compare our values with those found by previous investigators and with those measured in other samples of solar and galactic material. In particular, a comparison of ^(22)Ne/^(20)Ne measurements from various sources implies that GCRs are not simply an accelerated sample of the local interstellar medium.",
"doi": "10.1007/BF00170801",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1996-10",
"series_number": "1-2",
"volume": "78",
"issue": "1-2",
"pages": "149-154"
},
{
"id": "authors:ks654-asn52",
"collection": "authors",
"collection_id": "ks654-asn52",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140703-220236671",
"type": "article",
"title": "Ionization Processes in the Heliosphere - Rates and Methods of their Determination",
"author": [
{
"family_name": "Ruci\u0144ski",
"given_name": "D.",
"clpid": "Ruci\u0144ski-D"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Gloeckler",
"given_name": "G.",
"clpid": "Gloeckler-G"
},
{
"family_name": "Lazarus",
"given_name": "A. J.",
"clpid": "Lazarus-A-J"
},
{
"family_name": "M\u00f6bius",
"given_name": "E.",
"clpid": "M\u00f6bius-E"
},
{
"family_name": "Witte",
"given_name": "M.",
"clpid": "Witte-M"
}
],
"abstract": "The rates of the most important ionization processes acting in interplanetary space on interstellar H, He, C, O, Ne and Ar atoms are critically reviewed in the paper. Their long-term modulations in the period 1974 \u2013 1994 are reexamined using updated information on relevant cross-sections as well as direct or indirect data on variations of the solar wind/solar EUV fluxes based on IMP 8 measurements and monitoring of the solar 10.7 cm radio emission. It is shown that solar cycle related variations are pronounced (factor of \u223c 3 between maximum and minimum) especially for species such as He, Ne, C for which photoionization is the dominant loss process. Species sensitive primarily to the charge-exchange (as H) show only moderate fluctuations \u223c 20% around average. It is also demonstrated that new techniques that make use of simultaneous observations of neutral He atoms on direct and indirect orbits, or simultaneous measurements of He^+ and He^(++) pickup ions and solar wind particles can be useful tools for narrowing the uncertainties of the He photoionization rate caused by insufficient knowledge of the solar EUV flux and its variations.",
"doi": "10.1007/BF00170794",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1996-10",
"series_number": "1-2",
"volume": "78",
"issue": "1-2",
"pages": "73-76"
},
{
"id": "authors:ydbyt-b3s41",
"collection": "authors",
"collection_id": "ydbyt-b3s41",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140703-214818330",
"type": "article",
"title": "Composition of Anomalous Cosmic Rays and Implications for the Heliosphere",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We use energy spectra of anomalous cosmic rays (ACRs) measured with the Cosmic Ray instrument on the Voyager 1 and 2 spacecraft during the period 1994/157-313 to determine several parameters of interest to heliospheric studies. We estimate that the strength of the solar wind termination shock is 2.42 (-0.08, +0.04). We determine the composition of ACRs by estimating their differential energy spectra at the shock and find the following abundance ratios: H/He = 5.6 (-0.5, +0.6), C/He = 0.00048 \u00b1 0.00011, N/He = 0.011 \u00b1 0.001, O/He = 0.075 \u00b1 0.006, and Ne/He = 0.0050 \u00b1 0.0004. We correlate our observations with those of pickup ions to deduce that the long-term ionization rate of neutral nitrogen at 1 AU is ~8.3 \u00d7 10^(-7) s^(-1) and that the charge-exchange cross section for neutral N and solar wind protons is ~1.0 \u00d7 10^(-15) cm^2 at 1.1 keV. We estimate that the neutral C/He ratio in the outer heliosphere is 1.8(-0.7, +0.9) \u00d7 10^(-5). We also find that heavy ions are preferentially injected into the acceleration process at the termination shock.",
"doi": "10.1007/BF00170798",
"issn": "0038-6308",
"publisher": "Springer",
"publication": "Space Science Reviews",
"publication_date": "1996-10",
"series_number": "1-2",
"volume": "78",
"issue": "1-2",
"pages": "117-128"
},
{
"id": "authors:kkm3c-te598",
"collection": "authors",
"collection_id": "kkm3c-te598",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140703-214349007",
"type": "article",
"title": "Evidence for Multiply Charged Anomalous Cosmic Rays",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "New measurements from the SAMPEX spacecraft show that most anomalous cosmic ray (ACR) oxygen nuclei with energies above 20 MeV nucleon^(-1) are multiply ionized, with ionic charge states of Q = 2, Q = 3, and probably higher. This new result contrasts with lower energies, at which most ACRs are singly charged. The observed abundance of multiply charged ions agrees with estimates of the fraction of singly charged ACRs that undergo electron stripping during acceleration if the timescale for acceleration to 10 MeV nucleon^(-1) is ~1 yr. The existence of multiply charged ACRs helps explain their acceleration to high energies, and it has implications for several other studies.",
"doi": "10.1086/310169",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "1996-07-20",
"series_number": "1",
"volume": "466",
"issue": "1",
"pages": "L43-L46"
},
{
"id": "authors:2vg49-n8b06",
"collection": "authors",
"collection_id": "2vg49-n8b06",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140612-105003970",
"type": "article",
"title": "The Distance to the Solar Wind Termination Shock in 1993 and 1994 from Observations of Anomalous Cosmic Rays",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "Using data from the Voyager and Pioneer spacecraft, we examine the energy spectra of anomalous cosmic rays (ACRs) during 1992\u20131994, a period of rapidly increasing intensities of these particles in the outer heliosphere. The 1992 period appears to be in nonequilibrium, marked by a rapid decrease in the tilt of the current sheet from \u223c63\u00b0 to \u223c35\u00b0 and a complex, evolving magnetic topology that affects interplanetary drifts and drift acceleration along the solar wind termination shock. In addition, large propagating interplanetary disturbances in 1991 may have weakened the shock temporarily, reducing the intensity of accelerated ions. The 1993\u20131994 period appears to be in quasi-equilibrium, marked by a stable tilt of the current sheet and a steady, large-scale magnetic topology that provides stable conditions for propagation and acceleration. The ACR intensities of higher-rigidity particles rise slowly during this period, suggesting that the shock intensity has stabilized. At lower rigidities the ACR intensities are increasing rapidly, which we attribute to decreasing modulation. During 1994 days 157\u2013209, we estimate that the shock was at 85 \u00b1 5 AU. The shock strength s is estimated to be 2.63 \u00b1 0.14, significantly weaker than a strong shock (s = 4) and consistent with a termination shock modified by the pressure of galactic cosmic rays. By comparing these 1994 observations with those made in 1987, we estimate that the latitudinal gradient of ACR He with energies 31\u201357 MeV nucleon^(\u22121) is \u223c1.9%/deg along the shock from the equator to the pole. We estimate that the ratio of the efficiency of injection of He^+ to H^+ pickup ions into the acceleration process is 7.0 \u00b1 1.6.",
"doi": "10.1029/96JA00413",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1996-05",
"series_number": "A5",
"volume": "101",
"issue": "A5",
"pages": "11017-11025"
},
{
"id": "authors:fgd37-awd11",
"collection": "authors",
"collection_id": "fgd37-awd11",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140624-140158949",
"type": "article",
"title": "A Study of the Composition and Energy Spectra of Anomalous Cosmic Rays Using the Geomagnetic Field",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "We use instrumentation on SAMPEX and the Earth's field as a magnetic rigidity filter in a \"double spectrometer\" approach to measure the composition and energy spectra of anomalous cosmic rays (ACRs) with Z\u22656. A \"pure\" sample of anomalous cosmic ray C, N, O, and Ne is obtained, with no significant evidence for other species. The bulk of ACRs are now known to be singly-charged, and the geomagnetic filter allows their energy spectra to be measured to higher energies than before. The anomalous oxygen spectrum is found to extend to at least \u223c100 MeV/nuc, which has implications for models of the acceleration of these ions.",
"doi": "10.1029/96GL00423",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1996-03-15",
"series_number": "6",
"volume": "23",
"issue": "6",
"pages": "617-620"
},
{
"id": "authors:58mnk-qaq43",
"collection": "authors",
"collection_id": "58mnk-qaq43",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140219-110824481",
"type": "article",
"title": "Observations of Anomalous Cosmic-Ray Hydrogen from the Voyager Spacecraft",
"author": [
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "As Voyager 1 and 2 approach the solar wind termination shock, the hydrogen energy spectrum exhibits a\nrapidly increasing flux of anomalous cosmic-ray hydrogen, consistent with that observed for other anomalous\ncosmic-ray species. These results are consistent with the evidence for anomalous cosmic-ray hydrogen reported\nfrom Voyager observations during the period of minimum solar modulation in 1987.",
"doi": "10.1086/187941",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "1995-06-20",
"series_number": "2",
"volume": "446",
"issue": "2",
"pages": "L105-L108"
},
{
"id": "authors:58k5k-1cg32",
"collection": "authors",
"collection_id": "58k5k-1cg32",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140612-094752170",
"type": "article",
"title": "Anomalous Cosmic Ray Oxygen Gradients Throughout the Heliosphere",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Blake",
"given_name": "J. B.",
"clpid": "Blake-J-B"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Franz",
"given_name": "M.",
"clpid": "Franz-M"
},
{
"family_name": "Hovestadt",
"given_name": "D.",
"clpid": "Hovestadt-D"
},
{
"family_name": "Klecker",
"given_name": "B.",
"clpid": "Klecker-B"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "We have used data from the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX), Ulysses, Voyager 1, Voyager 2, and Pioneer 10 spacecraft to determine the radial and latitudinal gradients of anomalous cosmic ray oxygen at 10 MeV/nuc during the last half of 1993. These five spacecraft cover radial distances from 1 AU (SAMPEX) to 58 AU (P10) and latitudes to 41 deg S (Ulysses) and 32 deg N (V1). We find that the radial gradient is a decreasing function of radial distance, approximately r-n, with n = 1.7 +/- 0.7. The large-scale radial gradient between the inner and outer heliosphere is much smaller than it was during the last solar minimum period in approximately 1987. The latitudinal gradient is small and positive, 1.3 +/- 0.4 %/deg, as opposed to the large and negative latitudinal gradients found during 1987, but similar to the small positive latitudinal gradient measured during 1976 for anomalous cosmic ray helium. These observations confirm that effects of curvature and gradient drift in the large scale magnetic field of the Sun are important for establishing the three-dimensional intensity distributions of these particles in the heliosphere during periods of solar minimum conditions",
"doi": "10.1029/94GL03343",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1995-02-15",
"series_number": "4",
"volume": "22",
"issue": "4",
"pages": "341-344"
},
{
"id": "authors:zmsnk-p4f20",
"collection": "authors",
"collection_id": "zmsnk-p4f20",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140620-162104120",
"type": "article",
"title": "The Energy Spectra of Anomalous Cosmic Rays in the Outer Heliosphere During 1991-1994",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
}
],
"abstract": "Since the launch of the Voyager spacecraft in 1977, we have monitored the energy spectra of anomalous cosmic rays (ACRs) as a function of radial and latitudinal position over the course of the solar cycle, including two reversals of the Sun's magnetic field. The energy spectrum for ACR helium observed during the last solar minimum period in 1987 at approximately 23 AU showed a rather narrow peak at approximately 22 MeV/nuc. In 1978 at approximately 2 AU, this spectrum was much broader with a peak at lower energies, in agreement with theories of the acceleration and propagation of these particles which include curvature and gradient drift in the interplanetary magnetic field. Currently, in the outer heliosphere at the position of Voyager 1 (approximately 55 AU and 32 deg N), the energy spectrum of ACR helium has a peak energy at approximately 8 MeV/nuc, considerably lower than previously observed. At Voyager 2 (42 AU and 11 deg S), the energy spectrum is quite different, having a peak energy near 20 MeV/nuc. We will report on the evolution of the spectra of ACRs as observed by the instruments on the Voyager spacecraft as the fluxes again approach solar minimum levels, expected in 1994, and relate the observations to models of their propagation.",
"doi": "10.1016/0273-1177(95)00370-T",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "1995",
"series_number": "9",
"volume": "16",
"issue": "9",
"pages": "363"
},
{
"id": "authors:h4ef9-2qn05",
"collection": "authors",
"collection_id": "h4ef9-2qn05",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140612-132930616",
"type": "article",
"title": "Observations of Anomalous Cosmic Rays in the Heliosphere from the SAMPEX, Ulysses, Voyager, and Pioneer Spacecraft",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Blake",
"given_name": "B.",
"clpid": "Blake-B"
},
{
"family_name": "Fr\u00e4enz",
"given_name": "M.",
"clpid": "Fr\u00e4enz-M"
},
{
"family_name": "Klecker",
"given_name": "B.",
"clpid": "Klecker-B"
},
{
"family_name": "Hovestadt",
"given_name": "D.",
"clpid": "Hovestadt-D"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "The radial and latitudinal gradients of anomalous cosmic rays (ACRs) in the heliosphere are \nexpected to depend on the phase of the solar cycle. During the last solar minimum in 1987, when \npositive energetic particles were entering the heliosphere along the neutral current sheet, the \nradial gradient of these particles in the outer heliosphere was found to depend on the tilt of the \nsheet and was a minimum when the tilt assumed its minimum value. The latitudinal gradient was large \nand negative during this same period. On a large scale, the radial gradient from l to -40 AU was \nfound to decrease linearly with radial distance for ACR oxygen. These particle distributions are \nexpected to be different after the polarity reversal of the solar magnetic field, which occurred \n-1990. By July 1994, the Voyagers 1 and 2 (Vl and V2) and Pioneer 10 (PlO) spacecraft will be \npositioned in the outer heliosphere in the radial range 45 to 62 AU. V2 and PlO will be at \nrelatively low heliographic latitudes, while V l will be at 32\u00b0 N. In the inner heliosphere Ulysses \nwill be beyond 70\u00b0 S at a radial distance of 2.7 AU. The SAMPEX spacecraft is in a near-polar Earth \norbit. Using measurements of anomalous cosmic rays from instruments on these 5 spacecraft, we will \nreport on the temporal behavior of the fluxes and their radial and latitudinal gradients during the \ncurrent approach towards solar minimum. We will compare the results from those taken during the \nlast solar minimum period and relate these to current models of solar modulation.",
"doi": "10.1016/0273-1177(95)00357-K",
"issn": "0273-1177",
"publisher": "Elsevier",
"publication": "Advances in Space Research",
"publication_date": "1995",
"series_number": "9",
"volume": "16",
"issue": "9",
"pages": "337"
},
{
"id": "authors:9kwrj-27069",
"collection": "authors",
"collection_id": "9kwrj-27069",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140523-101203531",
"type": "article",
"title": "Geomagnetically Trapped Anomalous Cosmic Rays",
"author": [
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "Since its launch in July 1992, the polar-orbiting satellite SAMPEX has been collecting data on geomagnetically trapped heavy ions, predominantly O, N, and Ne, at energies \u2273 15 MeV/nucleon and in a narrow L shell range near L = 2. Their location, elemental composition, energy spectra, pitch angle distribution, and time variations all support the theory that these particles originated as singly ionized interplanetary anomalous cosmic rays that were stripped of electrons in the Earth's upper atmosphere and subsequently trapped. The O are observed primarily at pitch angles outside the atmospheric loss cones, consistent with a trapped population, and their distribution there is nearly isotropic. The abundances relative to O of the N, possibly Ne, and especially C are lower than the corresponding interplanetary values, which may be indicative of the trapping efficiencies. The distributions of trapped N, O, and Ne in energy and L shell suggest that most of the ions observed at the SAMPEX altitude of \u223c600 km are not fully stripped when initially trapped. A comparison of the trapped intensity with the much lower interplanetary intensity of anomalous cosmic rays provides model-dependent estimates of the product of the trapping probability and the average trapped particle lifetime against ionization losses in the residual atmosphere for particles that mirror near the SAMPEX altitude.",
"doi": "10.1029/94JA03140",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "1994-06-01",
"series_number": "A6",
"volume": "100",
"issue": "A6",
"pages": "9503"
},
{
"id": "authors:rvw83-0b451",
"collection": "authors",
"collection_id": "rvw83-0b451",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140520-100248179",
"type": "article",
"title": "Distance to the Solar Wind Termination Shock and the Source Flux of Anomalous Cosmic Rays During 1986-1988",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "We use observations of the intensity of anomalous cosmic ray helium and oxygen in the outer heliosphere near the last solar minimum period, in conjunction with solar observations of the tilt of the neutral current sheet, to estimate that the solar wind termination shock was at 67 \u00b1 5 AU during the time period 1986.7-1988.5. We find the source flux of anomalous cosmic rays at the shock to be 1.7 \u00b1 0.3 (m\u00b2 s sr MeV/nucleon)^(\u22121) for 7.1-17.1 MeV/nucleon anomalous cosmic ray oxygen and 4.3 \u00b1 0.8 (m\u00b2 s sr MeV/nucleon)^(\u22121) for 31-57 MeV/nucleon anomalous cosmic ray helium. We also estimate a source flux of anomalous cosmic ray hydrogen of 2.3 \u00b1 0.6 (m\u00b2 s sr MeV)^(\u22121) at 134 MeV. The resulting energy density of anomalous cosmic rays at the solar wind termination shock is \u223c0.03 eV/cm\u00b3, approximately 2% of the energy density of the solar wind at 67 AU.",
"doi": "10.1029/94JA00551",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "1994-06",
"series_number": "A6",
"volume": "99",
"issue": "A6",
"pages": "11547-11552"
},
{
"id": "authors:qt61x-72b60",
"collection": "authors",
"collection_id": "qt61x-72b60",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140516-132152344",
"type": "article",
"title": "Anomalous Cosmic Rays: Interstellar Interlopers in the Heliosphere and Magnetosphere",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "Since the beginning of the space age, it\nwas known that two main sources of energetic\nparticles pervade interplanetary space:\ngalactic cosmic rays (GCRs), which originate\nin sources outside the solar system, and solar energetic particles (SEPs), associated\nwith transient events on the Sun.\nBut over 20 years ago, instruments on the\nPioneer 1O, IMP 5, and IMP 7 spacecraft discovered\na third component of energetic particles\nknown as \"anomalous cosmic rays,\"\nthat represents a sample of nearby interstellar\nmaterial.\nOver the past 2 decades, ACRs have been\nused to study the acceleration and transport\nof energetic particles within the solar system,\ndeduce the global properties of the heliosphere-\nthe bubble of solar wind that envelopes\nthe solar system, and study the\ninterstellar material itself.\nIt has recently been shown that some of\nthese ACRs have become trapped in Earth's\nmagnetic field, where they form a radiation\nbelt composed of interstellar material (Figure\nI). Also, ACRs are being used to address a\nquestion that has existed ever since the discovery\nof the solar wind: \"How large is the\nheliosphere?\"",
"doi": "10.1029/94EO00864",
"issn": "0096-3941",
"publisher": "American Geophysical Union",
"publication": "Eos",
"publication_date": "1994-04-19",
"series_number": "16",
"volume": "75",
"issue": "16",
"pages": "185-193"
},
{
"id": "authors:960yq-3t819",
"collection": "authors",
"collection_id": "960yq-3t819",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140512-104159363",
"type": "article",
"title": "Development of an Interdigitated Pixel PIN Detector for Energetic Particle Spectroscopy in Space",
"author": [
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Rosenberg",
"given_name": "J. J.",
"clpid": "Rosenberg-J-J"
},
{
"family_name": "Cunningham",
"given_name": "T. J.",
"clpid": "Cunningham-T-J"
},
{
"family_name": "Mazed",
"given_name": "M.",
"clpid": "Mazed-M"
},
{
"family_name": "Holtzman",
"given_name": "M. J.",
"clpid": "Holtzman-M-J"
},
{
"family_name": "Fossum",
"given_name": "E. R.",
"clpid": "Fossum-E-R"
}
],
"abstract": "The development of a new two\u2010dimensional position\u2010sensitive detector for use in space\u2010borne energetic particle spectrometers is described. The novel feature of this device is the use of interdigitated pixels to provide both dimensions of position information from a single side of the detector, while a measurement of the energy deposition is derived from the opposite side. The advantage of this approach is that both good position resolution and excellent energy resolution can be achieved while at the same time realizing significant reductions in the complexity, power, and weight of the associated read\u2010out electronics.",
"doi": "10.1080/02757259309532200",
"issn": "0275-7257",
"publisher": "Taylor & Francis",
"publication": "Remote Sensing Reviews",
"publication_date": "1994",
"series_number": "1-3",
"volume": "8",
"issue": "1-3",
"pages": "245-253"
},
{
"id": "authors:0pekb-t8g18",
"collection": "authors",
"collection_id": "0pekb-t8g18",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140612-111816582",
"type": "article",
"title": "SAMPEX Measurements of Heavy Ions Trapped in the Magnetosphere",
"author": [
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Blake",
"given_name": "J. B.",
"clpid": "Blake-J-B"
}
],
"abstract": "New observations of >15 MeV/nuc trapped heavy ions\nwith Z 2 2 have been made by the SAMPEX spacecraft in low\npolar orbit. The composition of these ions, which are located\nprimarily around L = 2, is dominated by He, N, O, and Ne.\nThe N, O, and Ne ions are apparently trapped \"anomalous\ncosmic rays,\" while the origin of the trapped He flux is\npresently uncertain. These ions can affect the rate of single-event\nupsets (SEUs) in spacecraft hardware.",
"doi": "10.1109/23.273518",
"issn": "0018-9499",
"publisher": "IEEE",
"publication": "IEEE Transactions on Nuclear Science",
"publication_date": "1993-12",
"series_number": "6",
"volume": "40",
"issue": "6",
"pages": "1458-1462"
},
{
"id": "authors:xs10g-8mx27",
"collection": "authors",
"collection_id": "xs10g-8mx27",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140516-110810887",
"type": "article",
"title": "Coronal Abundances of Neon and Magnesium Isotopes from Solar Energetic Particles",
"author": [
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Leske",
"given_name": "R. A.",
"orcid": "0000-0002-0156-2414",
"clpid": "Leske-R-A"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The relative abundances of 22 to 70 Me V nucleon^(-l) Ne and Mg isotopes from two large flare-associated\nsolar energetic particle (SEP) events in 1992 October and November, are determined from data taken by the\nMass Spectrometer Telescope on the polar-orbiting SAMPEX satellite. After converting the measured abundances\nto coronal values, the average ^(22)Ne/^(20)Ne ratio is 0.076 \u00b1 0.008, consistent with the solar wind value of\n0.073 but significantly less than that of previous SEP measurements, in which the abundance of ^(22)Ne was\nsubstantially enhanced. The average ^(26)Mg/^(24)Mg ratio is 0.152 \u00b1 0.012, consistent with both previous SEP and\nother solar system measurements.",
"doi": "10.1086/187112",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "1993-11-20",
"series_number": "1",
"volume": "418",
"issue": "1",
"pages": "L45-L48"
},
{
"id": "authors:3bfrs-97g72",
"collection": "authors",
"collection_id": "3bfrs-97g72",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140520-091404026",
"type": "article",
"title": "The Return of the Anomalous Cosmic Rays to 1 AU in 1992",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Klecker",
"given_name": "B.",
"clpid": "Klecker-B"
},
{
"family_name": "Hovestadt",
"given_name": "D.",
"clpid": "Hovestadt-D"
},
{
"family_name": "Scholer",
"given_name": "M.",
"clpid": "Scholer-M"
},
{
"family_name": "Mason",
"given_name": "G. M.",
"orcid": "0000-0003-2169-9618",
"clpid": "Mason-G-M"
},
{
"family_name": "Mazur",
"given_name": "J. E.",
"clpid": "Mazur-J-E"
},
{
"family_name": "Hamilton",
"given_name": "D. C.",
"clpid": "Hamilton-D-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Blake",
"given_name": "J. B.",
"clpid": "Blake-J-B"
}
],
"abstract": "New observations of low energy (approximately 1 to 200 MeV/nuc) cosmic rays measured by three newly launched experiments on Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) during 1992 and 1993 show the strong presence of anomalous cosmic ray (ACR) nitrogen and oxygen, well before the approaching solar minimum. When compared with ACR temporal variations over the past two solar cycles we find that the 1992-1993 fluxes are approximately 5 to 10 times their level at corresponding neutron monitor counting rates in 1969-1970 and 1985",
"doi": "10.1029/93GL02493",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1993-10-22",
"series_number": "20",
"volume": "20",
"issue": "20",
"pages": "2263-2266"
},
{
"id": "authors:sn8vv-a9r24",
"collection": "authors",
"collection_id": "sn8vv-a9r24",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140520-095742074",
"type": "article",
"title": "SAMPEX Observations of Anomalous Cosmic Rays Trapped in the Magnetosphere",
"author": [
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
}
],
"abstract": "The Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX),\nlaunched July 3, 1992, into an 82 degree inclination, low-Earth orbit (670 x\n520 km), is the first of NASA's new line of Small Explorer (SMEX) missions.\nSAMPEX has been described in U.S. STEP News, Vol. 1, No. 6, December\n1991. The spacecraft carries four instruments designed to measure\nthe composition of energetic nuclei and electrons over a broad range in energy\nand intensity, including particles of solar, interplanetary, galactic,\nand magnetospheric origin. A detailed description of the spacecraft and\nthese instruments is given in the May 1993 issue of Geoscience and Remote\nSensing. Of the many studies that SAMPEX has conducted during its first\nyear of operation, one of the most interesting has been of a trapped radiation\nbelt encircling the Earth that contains high-energy N, 0, and Ne nuclei\nfrom the local interstellar medium. These observations, along with\nearlier work from a series of COSMOS satellites, confirm a prediction\nmade more than a decade ago. The process by which interste1lar material\nfinds its way into the magnetosphere involves a rather fascinating series of\nsteps.",
"publisher": "STEP International",
"publication": "STEP International",
"publication_date": "1993-10",
"series_number": "10",
"volume": "3",
"issue": "10",
"pages": "1-4"
},
{
"id": "authors:v8nss-m3g72",
"collection": "authors",
"collection_id": "v8nss-m3g72",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140304-145352097",
"type": "article",
"title": "New evidence for geomagnetically trapped anomalous cosmic rays",
"author": [
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We report new observations of \u2265 15 MeV/nuc trapped heavy ions with Z \u2265 2, made on the polar-orbiting SAMPEX spacecraft in late 1992 and early 1993. A trapped population that includes He, N, O, and Ne is found to be located at L \u2248 2. We conclude that the observed N, O, and Ne ions are \"anomalous\" cosmic rays, trapped by the mechanism proposed by Blake and Friesen. While it is not expected that this mechanism would also trap anomalous He, the characteristics of the trapped He population are generally consistent with those of N, O, and Ne.",
"doi": "10.1029/93GL01961",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1993-09-15",
"series_number": "18",
"volume": "20",
"issue": "18",
"pages": "2003-2006"
},
{
"id": "authors:fbwg7-htz45",
"collection": "authors",
"collection_id": "fbwg7-htz45",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140516-103709418",
"type": "article",
"title": "Estimate of the Distance to the Solar Wind Termination Shock from Gradients of Anomalous Cosmic Ray Oxygen",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "The radial gradient of anomalous cosmic ray oxygen measured instantaneously between Voyager 2 and Pioneer 10 during 1985-1988 is correlated with the inferred tilt of the heliospheric neutral sheet. This is consistent with a simple model in which the radial gradient is related to the length of the neutral sheet between the two spacecraft. With this model we show that the radial gradient and the tilt of the neutral sheet near the solar wind termination shock can be inferred from the Voyager and Pioneer observations. By comparing the time history of the inferred tilt with that derived from solar observations, we estimate that the termination shock was at 62 +5/-7 AU at solar minimum in 1987. At solar maximum the shock should be located at about 90 AU due to the increased pressure of the solar wind.",
"doi": "10.1029/93JA01173",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research B",
"publication_date": "1993-09-01",
"series_number": "A9",
"volume": "98",
"issue": "A9",
"pages": "15,165-15,168"
},
{
"id": "authors:3e6s9-27q49",
"collection": "authors",
"collection_id": "3e6s9-27q49",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140512-103823930",
"type": "article",
"title": "PET: A Proton/Electron Telescope for Studies of Magnetospheric, Solar, and Galactic Particles",
"author": [
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Baker",
"given_name": "D. N.",
"clpid": "Baker-D-N"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
},
{
"family_name": "Blake",
"given_name": "J. B.",
"clpid": "Blake-J-B"
},
{
"family_name": "Callis",
"given_name": "L. B.",
"clpid": "Callis-L-B"
}
],
"abstract": "The proton/electron telescope (PET) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide measurements of energetic electrons and light nuclei from solar, Galactic, and magnetospheric sources. PET is an all solid-state system that will measure the differential energy spectra of electrons from ~1 to ~30 MeV and H and He nuclei from ~20 to ~300 MeV/nucleon, with isotope resolution of H and He extending from ~20 to ~80 MeV/nucleon. As SAMPEX scans all local times and geomagnetic cutoffs over the course of its near-polar orbit, PET will characterize precipitating relativistic electron events during periods of declining solar activity, and it will examine whether the production rate of odd nitrogen and hydrogen molecules in the middle atmosphere by precipitating electrons is sufficient to affect O_3 depletion. In addition, PET will complement studies of the elemental and isotopic composition of energetic heavy (Z>2) nuclei on SAMPEX by providing measurements of H, He, and electrons. Finally, PET has limited capability to identify energetic positrons from potential natural and man-made sources.",
"doi": "10.1109/36.225523",
"issn": "0196-2892",
"publisher": "IEEE Transactions on Geoscience and Remote Sensing",
"publication": "IEEE Transactions on Geoscience and Remote Sensing",
"publication_date": "1993-05",
"series_number": "3",
"volume": "31",
"issue": "3",
"pages": "565-571"
},
{
"id": "authors:5ybza-tm133",
"collection": "authors",
"collection_id": "5ybza-tm133",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140307-151617567",
"type": "article",
"title": "MAST: a mass spectrometer telescope for studies of the isotopic composition of solar, anomalous, and galactic cosmic ray nuclei",
"author": [
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Cummings",
"given_name": "J. R.",
"clpid": "Cummings-J-R"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Kecman",
"given_name": "B.",
"clpid": "Kecman-B"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "von Rosenvinge",
"given_name": "T. T.",
"clpid": "von-Rosenvinge-T-T"
}
],
"abstract": "The mass spectrometer telescope (MAST) on SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) is designed to provide high-resolution measurements of the isotopic composition of energetic nuclei from He to Ni (Z=2 to 28) over the energy range from ~10 to several hundred MeV/nucleon. During large solar flares MAST will measure the isotopic abundances of solar energetic particles to determine directly the composition of the solar corona, while during solar quiet times MAST will study the isotopic composition of galactic cosmic rays. In addition, MAST will measure the isotopic composition of both interplanetary and trapped fluxes of anomalous cosmic rays, believed to be a sample of the nearby interstellar medium.",
"doi": "10.1109/36.225522",
"issn": "0196-2892",
"publisher": "IEEE",
"publication": "IEEE Transactions on Geoscience and Remote Sensing",
"publication_date": "1993-05",
"series_number": "3",
"volume": "31",
"issue": "3",
"pages": "557-564"
},
{
"id": "authors:3phjr-a2w10",
"collection": "authors",
"collection_id": "3phjr-a2w10",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140512-100311515",
"type": "article",
"title": "A Bevalac Calibration of a Scintillating Optical Fiber Hodoscope",
"author": [
{
"family_name": "Crary",
"given_name": "D. J.",
"clpid": "Crary-D-J"
},
{
"family_name": "Binns",
"given_name": "W. R.",
"orcid": "0000-0001-6110-3407",
"clpid": "Binns-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Klarmann",
"given_name": "J.",
"clpid": "Klarmann-J"
},
{
"family_name": "Lawrence",
"given_name": "D. J.",
"clpid": "Lawrence-D-J"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
}
],
"abstract": "As part of instrument definition activities for the Advanced Composition Explorer (ACE) we have evaluated a hodoscope comprised of scintillating fibers for possible use in the Cosmic Ray Isotope Spectrometer (CRIS). The hodoscope would determine the trajectories of individual cosmic ray nuclei with 3 \u2a7d Z \u2a7d 40 and energies up to several hundred MeV/n which stop in four silicon solid state telescopes. We report on the analysis of data from a December 1990 Bevalac calibration of a CRIS test model in which the hodoscope consisted of 200 \u03bcm, square cross section, scintillating fibers, and which used silicon detectors for dE/dx - E_(Tot) measurements. The positional resolution obtained with the fiber hodoscope was \u223c 60 \u03bcmfor iron nuclei at angles from 0\u201330\u00b0 with respect to the normal to the fiber planes. The detection efficiency for iron and silicon nuclei was determined to be > 99% for beam angles of \u2a7e 20\u00b0.",
"doi": "10.1016/0168-9002(92)90915-Q",
"issn": "0168-9002",
"publisher": "Elsevier",
"publication": "Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment",
"publication_date": "1992-06-01",
"series_number": "2-3",
"volume": "A316",
"issue": "2-3",
"pages": "311-317"
},
{
"id": "authors:qbvfb-29521",
"collection": "authors",
"collection_id": "qbvfb-29521",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140502-091740228",
"type": "article",
"title": "Energetic Charged Particles in the Magnetosphere of Neptune",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Looper",
"given_name": "M. D.",
"clpid": "Looper-M-D"
},
{
"family_name": "Selesnick",
"given_name": "R. S.",
"clpid": "Selesnick-R-S"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Chenette",
"given_name": "D. L.",
"clpid": "Chenette-D-L"
}
],
"abstract": "The Voyager 2 cosmic ray system (CRS) measured significant fluxes of energetic [\u2273 1\nmegaelectron volt (MeV)] trapped electrons and protons in the magnetosphere of\nNeptune. The intensities are maximum near a magnetic L shell of 7, decreasing closer\nto the planet because of absorption by satellites and rings. In the region of the inner\nsatellites of Neptune, the radiation belts have a complicated structure, which provides\nsome constraints on the magnetic field geometry of the inner magnetosphere. Electron\nphase-space densities have a positive radial gradient, indicating that they diffuse inward\nfrom a source in the outer magnetosphere. Electron spectra from 1 to 5 MeV are\ngenerally well represented by power laws with indices near 6, which harden in the\nregion of peak flux to power law indices of 4 to 5. Protons have significantly lower\nfluxes than electrons throughout the magnetosphere, with large anisotropies due to\nradial intensity gradients. The radiation belts resemble those of Uranus to the extent\nallowed by the different locations of the satellites, which limit the flux at each planet.",
"doi": "10.1126/science.246.4936.1489",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1989-12-15",
"series_number": "4936",
"volume": "246",
"issue": "4936",
"pages": "1489-1494"
},
{
"id": "authors:p4c06-66n86",
"collection": "authors",
"collection_id": "p4c06-66n86",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140501-103301989",
"type": "article",
"title": "Evidence for Anomalous Cosmic Ray Hydrogen",
"author": [
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We present evidence for the emergence of a measurable anomalous cosmic-ray hydrogen component in 1987 which may account for 20% - 40% of the total hydrogen flux at 60 MeV. Comparing this flux with that of anomalous cosmic-ray helium, the authors estimate that the H I/He I ratio in the very local interstellar medium is ~4, consistent with determinations from solar ultraviolet backscatter measurements.",
"doi": "10.1086/185316",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "1988-11-15",
"volume": "334",
"pages": "L77-L80"
},
{
"id": "authors:h465f-chr87",
"collection": "authors",
"collection_id": "h465f-chr87",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140212-133657111",
"type": "article",
"title": "Evidence for anomalous cosmic-ray hydrogen",
"author": [
{
"family_name": "Christian",
"given_name": "E. R.",
"orcid": "0000-0003-2134-3937",
"clpid": "Christian-E-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "We present evidence for the emergence of a measurable anomalous cosmic-ray hydrogen component in 1987\nwhich may account for 20%-40% of the total hydrogen flux at 60 MeV. Comparing this flux with that of\nanomalous cosmic-ray helium, we estimate that the H I/He I ratio in the very local interstellar medium is ~4,\nconsistent with determinations from solar ultraviolet backscatter measurements.",
"doi": "10.1086/185316",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "1988-11-15",
"series_number": "2",
"volume": "334",
"issue": "2",
"pages": "L77-L80"
},
{
"id": "authors:amfbn-5xg03",
"collection": "authors",
"collection_id": "amfbn-5xg03",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140430-091349465",
"type": "article",
"title": "Latitudinal and Radial Gradients of Anomalous and Galactic Cosmic Rays in the Outer Heliosphere",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "We have used measurements from instruments on Voyagers 1 and 2 and Pioneer 10 to derive simultaneous radial and latitudinal gradients of anomalous cosmic-ray oxygen during the latter part of 1985. We find that in the energy interval from 7.1-30.6 MeV/nucleon the latitudinal gradient is \u22123 to \u22124%/deg. The sign of the latitudinal gradient is opposite to that reported for the last solar cycle when the solar magnetic field polarity was reversed, as predicted by propagation models in which curvature and gradient drifts are significant. The ratios of the radial and latitudinal gradients of anomalous oxygen, anomalous helium, and galactic cosmic rays are similar, also in agreement with drift theory predictions. Based on drift theory, these observed ratios, which are near unity, lead to estimates of \u03ba/\u03b2 in the range of 3-8 \u00d7 10^(22) cm\u00b2/sec at 24.9 AU for particles with rigidities of \u223c2-3 GV.",
"doi": "10.1029/GL014i003p00174",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1987-03",
"series_number": "3",
"volume": "14",
"issue": "3",
"pages": "174-177"
},
{
"id": "authors:pdfg8-sa872",
"collection": "authors",
"collection_id": "pdfg8-sa872",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140219-103051736",
"type": "article",
"title": "Solar cycle variations of anomalous ^4He as deduced by studies of cosmic ray ^3He",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
}
],
"abstract": "Voyager 1 and 2 observations have been used to derive the energy spectrum of 'anomalous' cosmic ray (ACR) helium using a technique based on the separation of the isotopes of He. Previously reported observations show that the ACR oxygen spectrum underwent a change in shape following the solar magnetic field reversal in 1980; in this paper we present evidence for a corresponding change in the ACR helium spectrum. We find that the energy spectra of ACR helium and oxygen and galactic cosmic ray (GCR) ^4He and ^3He can be reproduced both before and after the field reversal using a simple solar modulation model in which the effects of curvature and gradient drifts are arbitrarily neglected.",
"doi": "10.1029/GL013i010p01043",
"issn": "0094-8276",
"publisher": "American Geophysical Union",
"publication": "Geophysical Research Letters",
"publication_date": "1986-10",
"series_number": "10",
"volume": "13",
"issue": "10",
"pages": "1043-1046"
},
{
"id": "authors:w2bcj-myj31",
"collection": "authors",
"collection_id": "w2bcj-myj31",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140429-142543314",
"type": "article",
"title": "Energetic Charged Particles in the Uranian Magnetosphere",
"author": [
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Cooper",
"given_name": "J. F.",
"clpid": "Cooper-J-F"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "McGuire",
"given_name": "R.",
"clpid": "McGuire-R"
},
{
"family_name": "Chenette",
"given_name": "D. L.",
"clpid": "Chenette-D-L"
}
],
"abstract": "During the encounter with Uranus, the cosmic ray system on Voyager 2 measured\nsignificant fluxes of energetic electrons and protons in the regions of the planet's\nmagnetosphere where these particles could be stably trapped. The radial distribution of\nelectrons with energies of megaelectron volts is strongly modulated by the sweeping\neffects of the three major inner satellites Miranda, Ariel, and Umbriel. The phase space\ndensity gradient of these electrons indicates that they are diffusing radially inward\nfrom a source in the outer magnetosphere or magnetotail. Differences in the energy\nspectra of protons having energies of approximately 1 to 8 megaelectron volts from\ntwo different directions indicate a strong dependence on pitch angle. From the\nlocations of the absorption signatures observed in the electron flux, a centered dipole\nmodel for the magnetic field of Uranus with a tilt of 60.1 degrees has been derived, and\na rotation period of the planet of 17.4 hours has also been calculated. This model\nprovides independent confirmation of more precise determinations made by other\nVoyager experiments.",
"doi": "10.1126/science.233.4759.93",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1986-07-04",
"series_number": "4759",
"volume": "233",
"issue": "4759",
"pages": "93-97"
},
{
"id": "authors:xfacj-h5f17",
"collection": "authors",
"collection_id": "xfacj-h5f17",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140429-131447506",
"type": "article",
"title": "Differential Measurement and Model Calculations of Cosmic-Ray Latitudinal Gradient with Respect to the Heliospheric Current Sheet",
"author": [
{
"family_name": "Christon",
"given_name": "S. P.",
"clpid": "Christon-S-P"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Behannon",
"given_name": "K. W.",
"clpid": "Behannon-K-W"
},
{
"family_name": "Burlaga",
"given_name": "L. F.",
"orcid": "0000-0002-5569-1553",
"clpid": "Burlaga-L-F"
},
{
"family_name": "Jokipii",
"given_name": "J. R.",
"clpid": "Jokipii-J-R"
},
{
"family_name": "Kota",
"given_name": "J.",
"clpid": "Kota-J"
}
],
"abstract": "Simultaneous magnetic field and charged particle measurements from the Voyager spacecraft with heliographic latitude separations of >10\u00b0 are used to investigate the distribution of \u223c1-GeV galactic cosmic ray protons with respect to the heliospheric current sheet in the outer solar system. By comparing the ratio of cosmic ray flux at Voyager 1 to that at Voyager 2 during periods of relatively quiet interplanetary conditions when the spacecraft are either both north or both south of the heliospheric current sheet, we derive an average latitude component of the gradient of the cosmic ray flux on opposite sides of the current sheet under restricted interplanetary conditions of \u22120.22\u00b10.03%/deg, equivalent to a decrease of \u223c1%/AU away from the current sheet at \u223c12 AU. Our results for these limited periods are in qualitative agreement with propagation models incorporating particle drifts.",
"doi": "10.1029/JA091iA03p02867",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "1986-03-01",
"series_number": "A3",
"volume": "91",
"issue": "A3",
"pages": "2867-2877"
},
{
"id": "authors:xpahp-5p874",
"collection": "authors",
"collection_id": "xpahp-5p874",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140429-104215151",
"type": "article",
"title": "Changes in the Energy Spectrum of Anomalous Oxygen During 1977-1985",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "We have used data from the cosmic ray experiments on the Voyager and Pioneer 10 spacecraft during the period 1977\u20131985 to measure the energy spectrum of oxygen with 4\u2013125 MeV/nucleon, with particular emphasis on the energy interval from \u223c4 to 30 MeV/nucleon, where the \"anomalous\" component of cosmic rays is dominant. This time period includes the sunspot minimum period at the beginning of solar cycle 21, the time of the solar magnetic field reversal in 1980, the maximum solar modulation period of 1981\u20131983, and part of the recovery of the solar cycle through early 1985. We find that the spectrum of anomalous oxygen changes dramatically after the middle of 1980, with the peak or plateau region of the differential spectrum shifting to a higher energy. This change does not appear to be due to the increasing radial distance of the spacecraft in this time period, nor does it appear to be simply correlated with the level of modulation. The energy shift also appears to be significantly greater in the ecliptic plane than at 24\u00b0 north latitude (the heliographic position of Voyager 1 at the end of the time period).",
"doi": "10.1029/JA091iA03p02896",
"issn": "0148-0227",
"publisher": "American Geophysical Union",
"publication": "Journal of Geophysical Research A",
"publication_date": "1986-03-01",
"series_number": "A3",
"volume": "91",
"issue": "A3",
"pages": "2896-2902"
},
{
"id": "authors:3tca9-zv184",
"collection": "authors",
"collection_id": "3tca9-zv184",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140408-115652188",
"type": "article",
"title": "Evidence that the anomalous cosmic-ray component is singly ionized",
"author": [
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Webber",
"given_name": "W. R.",
"clpid": "Webber-W-R"
}
],
"abstract": "We have used data from the Cosmic Ray Subsystem on the Voyager spacecraft to measure the spectra of He, C, N, O, and Ne with 4-124 MeV per nucleon (for O) during solar minimum conditions near the end of 1977. By subtracting both a low-energy interplanetary component and the high-energy galactic component we have determined the energy spectra of the \"anomalous\" cosmic-ray species He, N, O, and Ne. The energy dependences of such spectra depend upon the charge state of the particles, their source spectra, and the rigidity dependence of the diffusion coefficient. If the source spectra at the boundary of the modulation region have similar power-law energy dependences, then the observed energy spectra indicate that the anomalous particles are singly ionized.",
"doi": "10.1086/184407",
"issn": "2041-8205",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal Letters",
"publication_date": "1984-12-15",
"series_number": "2",
"volume": "287",
"issue": "2",
"pages": "L99-L103"
},
{
"id": "authors:ff5ns-6zt61",
"collection": "authors",
"collection_id": "ff5ns-6zt61",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140210-140754733",
"type": "article",
"title": "Energetic Charged Particles in Saturn's Magnetosphere: Voyager 2 Results",
"author": [
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
},
{
"family_name": "Chenette",
"given_name": "D. L.",
"clpid": "Chenette-D-L"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Schardt",
"given_name": "A. W.",
"clpid": "Schardt-A-W"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
}
],
"abstract": "Results from the cosmic-ray system on Voyager 2 in Saturn's magnetosphere are presented. During the inbound pass through the outer magnetosphere, the \u2265 0.43-million-electron-volt proton flux was more intense, and both the proton and electron fluxes were more variable, than previously observed. These changes are attributed to the influence on the magnetosphere of variations in the solar wind conditions. Outbound, beyond 18 Saturn radii, impulsive bursts of 0.14- to > 1.0- million-electron-volt electrons were observed. In the inner magnetosphere, the charged particle absorption signatures of Mimas, Enceladus, and Tethys are used to constrain the possible tilt and offset of Saturn's internal magnetic dipole. At \u223c 3 Saturn radii, a transient decrease was observed in the electron flux which was not due to Mimas. Characteristics of this decrease suggest the existence of additional material, perhaps another satellite, in the orbit of Mimas.",
"doi": "10.1126/science.215.4532.577",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1982-01-29",
"series_number": "4532",
"volume": "215",
"issue": "4532",
"pages": "577-582"
},
{
"id": "authors:k3vhe-24s63",
"collection": "authors",
"collection_id": "k3vhe-24s63",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140205-155430624",
"type": "article",
"title": "Energetic Charged Particles in Saturn's Magnetosphere:\n Voyager 1 Results",
"author": [
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
},
{
"family_name": "Chenette",
"given_name": "D. L.",
"clpid": "Chenette-D-L"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Schardt",
"given_name": "A. W.",
"clpid": "Schardt-A-W"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
}
],
"abstract": "Voyager 1 provided the first look at Saturn's magnetotail and magnetosphere during relatively quiet interplanetary conditions. This report discusses the energetic particle populations of the outer magnetosphere of Saturn and absorption features associated with Titan and Rhea, and compares these observations with Pioneer 11 data of a year earlier. The trapped proton fluxes had soft spectra, represented by power laws E^\u2013\u03b3 in kinetic energy E, with \u03b3 \u223c 7 in the outer magnetosphere and \u03b3 \u223c 9 in the magnetotail. Structure associated with the magnetotial was observed as close as 10 Saturn radii (Rs) on the outbound trajectory. The proton and electron fluxes in the outer magnetosphere and in the magnetotail were variable and appeared to respond to changes in interplanetary conditions. Protons with energies \u2265 2 million electron volts had free access to the magnetosphere from interplanetary space and were not stably trapped outside \u223c 7.5 Rs.",
"doi": "10.1126/science.212.4491.231",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1981-04-10",
"series_number": "4491",
"volume": "212",
"issue": "4491",
"pages": "231-234"
},
{
"id": "authors:vj0ph-jm616",
"collection": "authors",
"collection_id": "vj0ph-jm616",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140206-162824597",
"type": "article",
"title": "Voyager 2: Energetic Ions and Electrons in the Jovian Magnetosphere",
"author": [
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Gehrels",
"given_name": "N.",
"clpid": "Gehrels-N"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Schardt",
"given_name": "A. W.",
"clpid": "Schardt-A-W"
},
{
"family_name": "Conlon",
"given_name": "T. F.",
"clpid": "Conlon-T-F"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
}
],
"abstract": "The Voyager 2 encounter has enhanced our understanding of earlier results and provided measurements beyond 160 Jupiter radii (RJ) in the magnetotail. Significant fluxes of energetic sulfur and oxygen nuclei (4 to 15 million electron volts per nucleon) of Jovian origin were observed inside 25 RJ, and the gradient in phase space density at 12 RJ indicates that the ions are diffusing inward. A substantially longer time delay versus distance was found for proton flux maxima in the active hemisphere in the magnetotail at Jovicentric longitudes \u03bbIII, = 260\u00b0 to 320\u00b0 than in the inactive hemisphere at \u03bbIII, = 85\u00b0 to l10\u00b0. These delays can be related to the radial motion of plasma expanding into the magnetotail, and differences in the expansion speeds between the active and inactive hemispheres can produce rarefaction regions in trapped particles. It is suggested that the 10-hour modulation of interplanetary Jovian electrons may be associated with the arrival at the dawn magnetopause of a rarefaction region each planetary rotation.",
"doi": "10.1126/science.206.4421.984",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1979-11-23",
"series_number": "4421",
"volume": "206",
"issue": "4421",
"pages": "984-987"
},
{
"id": "authors:xfk3m-wkf28",
"collection": "authors",
"collection_id": "xfk3m-wkf28",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140417-135117781",
"type": "article",
"title": "Voyager 2: Energetic Ions and Electrons in the Jovian Magnetosphere",
"author": [
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Gehrels",
"given_name": "N.",
"clpid": "Gehrels-N"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Schardt",
"given_name": "A. W.",
"clpid": "Schardt-A-W"
},
{
"family_name": "Conlon",
"given_name": "T. F.",
"clpid": "Conlon-T-F"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
}
],
"abstract": "Abstract. The Voyager 2 encounter has enhanced our understanding of earlier\nresults and provided measurements beyond 160 Jupiter radii (RJ) in the magnetotail. Significant fluxes of energetic sulfur and oxygen nuclei (4 to 15 million electron volts per nucleon) of Jovian origin were observed inside 25R^j, and the gradient in phase space density at 12 R^J indicates that the ions are diffusing inward. A substantially longer time delay versus distance was found for proton flux maxima in the active\nhemisphere in the magnetotail at Jovicentric longitudes Am = 260\u00b0 to 320\u00b0 than in the inactive hemisphere at Am = 85\u00b0 to 110\u00b0. These delays can be related to the radial motion of plasma expanding into the magnetotail, and differences in the expansion speeds between the active and inactive hemispheres can produce rarefaction regions in trapped particles. It is suggested that the JO-hour modulation of interplanetary Jovian electrons may be associated with the arrival at the dawn magnetopause of a rarefaction region each planetary rotation.",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1979-11-13",
"series_number": "4421",
"volume": "206",
"issue": "4421",
"pages": "984-987"
},
{
"id": "authors:h254q-afn90",
"collection": "authors",
"collection_id": "h254q-afn90",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140205-163501718",
"type": "article",
"title": "Voyager 1: Energetic Ions and Electrons in the Jovian Magnetosphere",
"author": [
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
},
{
"family_name": "Cook",
"given_name": "W. R.",
"clpid": "Cook-W-R"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Gehrels",
"given_name": "N.",
"clpid": "Gehrels-N"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Schardt",
"given_name": "A. W.",
"clpid": "Schardt-A-W"
},
{
"family_name": "Conlon",
"given_name": "T.",
"clpid": "Conlon-T"
},
{
"family_name": "Lal",
"given_name": "N.",
"clpid": "Lal-N"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
}
],
"abstract": "The observations of the cosmic-ray subsystem have added significantly to our knowledge of Jupiter's magnetosphere. The most surprising result is the existence of energetic sulfur, sodium, and oxygen nuclei with energies above 7 megaelectron volts per nucleon which were found inside of Io's orbit. Also, significant fluxes of similarly energetic ions reflecting solar cosmic-ray composition were observed\nthroughout the magnetosphere beyond 11 times the radius of Jupiter. It was also found that energetic protons are enhanced by 30 to 70 percent in the active\nhemisphere. Finally, the first observations were made of the magnetospheric tail in the dawn direction out to 160 Jupiter radii.",
"doi": "10.1126/science.204.4396.1003",
"issn": "0036-8075",
"publisher": "American Association for the Advancement of Science",
"publication": "Science",
"publication_date": "1979-06-01",
"series_number": "4396",
"volume": "204",
"issue": "4396",
"pages": "1003-1007"
},
{
"id": "authors:3m3nj-nnj50",
"collection": "authors",
"collection_id": "3m3nj-nnj50",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-110553333",
"type": "article",
"title": "The Voyager Cosmic Ray Experiment",
"author": [
{
"family_name": "Stilwell",
"given_name": "D. E.",
"clpid": "Stilwell-D-E"
},
{
"family_name": "Davis",
"given_name": "W. D.",
"clpid": "Davis-W-D"
},
{
"family_name": "Joyce",
"given_name": "R. M.",
"clpid": "Joyce-R-M"
},
{
"family_name": "McDonald",
"given_name": "F. B.",
"clpid": "McDonald-F-B"
},
{
"family_name": "Trainor",
"given_name": "J. H.",
"clpid": "Trainor-J-H"
},
{
"family_name": "Althouse",
"given_name": "W. E.",
"clpid": "Althouse-W-E"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
}
],
"abstract": "The Voyager Cosmic Ray Experiment includes seven dE/dx-\nE telescopes to measure the energy and charge of\nparticles of 1 \u2264 Z \u2264 26 in the energy range 1-500 MeV/\nnucleon and to measure electron energy in the range\n3 \u2264 E_e \u2264 110 MeV. Isotopic composition of hydrogen\nthrough sulfur in the range up to 75 MeV/nucleon can\nalso be resolved. The electronic systems include a\ndual-gain, charge sensitive preamplifier, 4096-channel\npulse height analyzers for three parameter analysis of\nselected events, and an event type readout polling\nscheme to maximize the use of available telemetry\nspace and to enhance the occurrence of rare events in\nthe data. Details of the detector, electronic and\nmechanical design are presented.",
"doi": "10.1109/TNS.1979.4329683",
"issn": "0018-9499",
"publisher": "IEEE",
"publication": "IEEE Transactions on Nuclear Science",
"publication_date": "1979-02",
"series_number": "1",
"volume": "26",
"issue": "1",
"pages": "513-520"
},
{
"id": "authors:q892j-zpx42",
"collection": "authors",
"collection_id": "q892j-zpx42",
"cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140205-074259302",
"type": "article",
"title": "A Cosmic Ray Isotope Spectrometer",
"author": [
{
"family_name": "Althouse",
"given_name": "W. E.",
"clpid": "Althouse-W-E"
},
{
"family_name": "Cummings",
"given_name": "A. C.",
"orcid": "0000-0002-3840-7696",
"clpid": "Cummings-A-C"
},
{
"family_name": "Garrard",
"given_name": "T. L.",
"clpid": "Garrard-T-L"
},
{
"family_name": "Mewaldt",
"given_name": "R. A.",
"orcid": "0000-0003-2178-9111",
"clpid": "Mewaldt-R-A"
},
{
"family_name": "Stone",
"given_name": "E. C.",
"orcid": "0000-0002-2010-5462",
"clpid": "Stone-E-C"
},
{
"family_name": "Vogt",
"given_name": "R. E.",
"clpid": "Vogt-R-E"
}
],
"abstract": "We describe a new instrument to be flown on ISEE-C which is optimized to measure the isotopic composition of solar and galactic cosmic rays with ~5 to ~250 MeV/nucleon. A mass resolution of \u227e 0.3 AMU should be achieved for all elements with charge Z \u2264 30.",
"doi": "10.1109/TGE.1978.294547",
"issn": "0018-9413",
"publisher": "IEEE",
"publication": "IEEE Transactions on Geoscience Electronics",
"publication_date": "1978-07",
"series_number": "3",
"volume": "16",
"issue": "3",
"pages": "204-207"
}
]