Absorption in a Hot Plasma near the Second Harmonic of the Electron Cyclotron Frequency

• Published in: The Physics of fluids (1958) 1968-01, Vol.11 (5), p.1076-1084
• Main Authors: Arunasalam, V., Meservey, E. B., Gurnee, M. N., Davidson, R. C.
• Format: Article
• Language: English
• ISSN: 0031-9171; 2163-4998
• DOI: 10.1063/1.1692046

Analysis is presented of 4‐mm microwave propagation in the extraordinary mode (for propagation angles of 76°, 90°, and 104° to the external magnetic field), near the second harmonic of the electron cyclotron frequency, across reasonably uniform, highly ionized cylindrical plasma columns (approximately 3, 4, and 5 in. in diameter) confined in a homogeneous (0.05%) magnetic field in the Model C stellarator. Reasonably good agreement with the general predictions of the conventional collisionless hot‐plasma theory is obtained. In particular, the measured values of the width, the depth, and the strength of the experimentally detected absorption resonances fall within ±50% of the corresponding theoretically expected values. For these experiments the electron densities are typically in the range of 10 11 to 10 13 per cm 3 ; the electron temperatures are in the range of 5‐35 eV; and the electron collision frequencies ν are such that ν/ω ≲ 5 × 10 −5 , where ω is the angular frequency of the incident microwave beam.