[
    {
        "id": "thesis:8562",
        "collection": "thesis",
        "collection_id": "8562",
        "cite_using_url": "https://resolver.caltech.edu/CaltechTHESIS:07182014-104710068",
        "primary_object_url": {
            "basename": "HWANG_DLSQ_1979.pdf",
            "content": "final",
            "filesize": 34325827,
            "license": "other",
            "mime_type": "application/pdf",
            "url": "/8562/1/HWANG_DLSQ_1979.pdf",
            "version": "v4.0.0"
        },
        "type": "thesis",
        "title": "Propagation of the Fast Magnetosonic Wave in a Tokamak Plasma",
        "author": [
            {
                "family_name": "Hwang",
                "given_name": "David Li-Shui Quek",
                "clpid": "Hwang-David-Li-Shui-Quek"
            }
        ],
        "thesis_advisor": [
            {
                "family_name": "Gould",
                "given_name": "Roy Walter",
                "clpid": "Gould-R-W"
            }
        ],
        "thesis_committee": [
            {
                "family_name": "Unknown",
                "given_name": "Unknown"
            }
        ],
        "local_group": [
            {
                "literal": "div_eng"
            }
        ],
        "abstract": "<p>The propagation of the fast magnetosonic wave in a tokamak\r\nplasma has been investigated at low power, between 10 and 300 watts,\r\nas a prelude to future heating experiments.</p>\r\n\r\n<p>The attention of the experiments has been focused on the understanding\r\nof the coupling between a loop antenna and a plasma-filled\r\ncavity. Special emphasis has been given to the measurement of the complex\r\nloading impedance of the plasma. The importance of this measurement\r\nis that once the complex loading impedance of the plasma is known,\r\na matching network can be designed so that the r.f. generator impedance\r\ncan be matched to one of the cavity modes, thus delivering maximum\r\npower to the plasma. For future heating experiments it will be essential\r\nto be able to match the generator impedance to a cavity mode in\r\norder to couple the r.f. energy efficiently to the plasma.</p>\r\n\r\n<p>As a consequence of the complex impedance measurements, it was\r\ndiscovered that the designs of the transmitting antenna and the impedance\r\nmatching network are both crucial. The losses in the antenna and\r\nthe matching network must be kept below the plasma loading in order to\r\nbe able to detect the complex plasma loading impedance. This is even\r\nmore important in future heating experiments, because the fundamental\r\nbasis for efficient heating before any other consideration is to deliver\r\nmore energy into the plasma than is dissipated in the antenna system.</p>\r\n\r\n<p>The characteristics of the magnetosonic cavity modes are confirmed\r\nby three different methods. First, the cavity modes are observed\r\nas voltage maxima at the output of a six-turn receiving probe.\r\nSecond, they also appear as maxima in the input resistance of the transmitting\r\nantenna. Finally, when the real and imaginary parts of the\r\nmeasured complex input impedance of the antenna are plotted in the\r\ncomplex impedance plane, the resulting curves are approximately circles,\r\nindicating a resonance phenomenon. </p>\r\n\r\n<p>The observed plasma loading resistances at the various cavity\r\nmodes are as high as 3 to 4 times the basic antenna resistance (~ .4 \u2126).\r\nThe estimated cavity Q\u2019s were between 400 and 700. This means that\r\nefficient energy coupling into the tokamak and low losses in the antenna\r\nsystem are possible. </p>",
        "doi": "10.7907/f15y-jy67",
        "publication_date": "1979",
        "thesis_type": "phd",
        "thesis_year": "1979"
    }
]