Nonlinear excitation of a geodesic acoustic mode by toroidal Alfven eigenmodes and the impact on plasma performance
Nonlinear excitation of a geodesic acoustic mode by toroidal Alfven eigenmodes and the impact on plasma performance
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环形阿尔文本征模对测地线声模的非线性激发及其对等离子体性能的影响
DOI：
10.1088/1741-4326/ab1285
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发表时间：
2019
期刊：
影响因子：
3.3
通讯作者：
Chen Wei
中科院分区：
文献类型：
--
作者：
Qiu Zhiyong;Chen Liu;Zonca Fulvio;Chen Wei
利用非线性陀螺动力学理论研究了环形Alfvén本征模（TAE）对测地线声模（GAM）的自发非线性激发。发现非线性衰减过程依赖于热离子值。这里，是等离子体的热磁压力比。在低限条件下，TAE衰减为GAM和TAE的下边带;在高限条件下，TAE衰减为GAM和TAE的下边带。这两种情况下的自发衰变条件进行了研究。导出了GAM和子波的非线性饱和能级。计算了相应的能量平衡和波粒能量向热等离子体的转移。热等离子体加热的影响进行了讨论。
Spontaneous nonlinear excitation of a geodesic acoustic mode (GAM) by a toroidal Alfvén eigenmode (TAE) is investigated using nonlinear gyrokinetic theory. It is found that the nonlinear decay process depends on the thermal ion value. Here, is the plasma thermal to magnetic pressure ratio. In the low-limit, a TAE decays into a GAM and a lower TAE sideband in the toroidicity induced shear Alfvén wave continuous spectrum gap; while in the high-limit, a TAE decays into a GAM and a propagating kinetic TAE in the continuum. Both cases are investigated for the spontaneous decay conditions. The nonlinear saturation levels of both the GAM and daughter wave are derived. The corresponding power balance and wave particle power transfer to thermal plasma are computed. Implications for thermal plasma heating are also discussed.