The effects of oblique incidences on the XB mode conversion in the electron cyclotron range of frequency

被引:1
|
作者
Jia, Guozhang [1 ,2 ]
Gao, Zhe [3 ]
机构
[1] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China
[2] Chinese Acad Sci, Ctr Magnet Fus Theory, Hefei 230031, Peoples R China
[3] Tsinghua Univ, Dept Engn Phys, Beijing 100084, Peoples R China
关键词
BERNSTEIN WAVES;
D O I
10.1063/1.4976324
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
The linear conversion from a fast extraordinary mode to a Bernstein mode (XB) in the electron cyclotron range of frequency is revisited numerically by using a simplified kinetic model. The corresponding wave equations are solved as a standard two-point boundary value problem, where the self-consistent boundary conditions are applied and the scattering coefficients are calculated accordingly. The numerical calculation of the XB conversion efficiency is compared with the analytical formula for the normal incidence (along the direction perpendicular to the equilibrium magnetic field and parallel to the density gradient), where a reasonable agreement is found. The effects of incident angles represented by refractive indexes on the conversion efficiency are analyzed. It is shown that as the incident angle deviates from the normal incidence, the efficiency of XB conversion decreases significantly. The results also indicate that the power loss in the XB process can be ascribed to the reflected fast extraordinary mode and the reflected-converted ordinary mode. The symmetry of the conversion efficiency about the incident angle is discussed, and the rigid restriction on the scale length of the density variation for effective XB conversions can be possibly alleviated through altering the injection direction in realistic experiments.
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页数:5
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