Destabilization of beta-induced Alfven eigenmodes by energetic trapped electrons in tokamak
Destabilization of beta-induced Alfven eigenmodes by energetic trapped electrons in tokamak
复制标题
托卡马克中高能俘获电子对 β 诱导的阿尔文本征模的不稳定
DOI：
10.1088/1741-4326/ab7f15
复制
发表时间：
2020
期刊：
影响因子：
3.3
通讯作者：
Wei Chen
中科院分区：
文献类型：
--
作者：
Ruirui Ma;Zhiyong Qiu;Yueyan Li;Wei Chen
研究了低磁剪切托卡马克等离子体中磁俘获高能电子进动共振激发的高环形模数（n）β诱导Alfvén本征模的稳定性。导出了能量电子β诱导Alfvén本征模（e-BAE）的色散关系，并用解析和数值方法求解。结果表明，俘获的高能电子对e-BAE色散关系的贡献仅限于BAE的理想MHD结构。数值计算结果表明，对于典型的平衡参数，高能电子可以使e-BAE不稳定，模式频率与实验观察一致。改变背景等离子体参数可以导致e-BAE和高能粒子模式之间的转换。此外，e-BAE频率和增长率对高能电子参数的依赖关系表明，增长率单调增加（减少）的高能电子密度（归一化的高能电子密度标度长度），和频率的影响不大。频率和生长速率对高能电子温度敏感，并存在一个最大生长速率。
The stability of high torodial mode number (n) beta-induced Alfvén eigenmodes excited by precessional resonance of magnetically trapped energetic electrons in low magnetic-shear tokamak plasma is investigated. The dispersion relation of the energetic-electron beta-induced Alfvén eigenmodes (e-BAE) is derived and solved analytically and numerically. It is found that the contribution of the trapped energetic electrons to the e-BAE dispersion relation is limited to the ideal MHD structure of the BAE. Numerical results show that, for typical equilibrium parameters, the e-BAE can be destabilized by the energetic electrons, and the mode frequency is consistent with the experimental observation. Varying the background plasma parameters can lead to transitions between e-BAEs and energetic particle modes. Moreover, the dependence of the e-BAE frequencies and growth rates on energetic electron parameters shows that the growth rates monotonically increase (decrease) with the energetic electron density (the normalized energetic electron density scale length), and the frequencies are not much affected. The frequency and growth rate are sensitive to the energetic electron temperature, and there exists a maximum growth rate.