Fast particle destabilization of toroidal Alfven eigenmodes
Fast particle destabilization of toroidal Alfven eigenmodes
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DOI：
10.1088/0029-5515/35/12/i28
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发表时间：
1995-12
期刊：
影响因子：
3.3
通讯作者：
C. Cheng;N. Gorelenkov;C. Hsu
中科院分区：
文献类型：
--
作者：
C. Cheng;N. Gorelenkov;C. Hsu
在包含全热离子有限拉莫尔半径效应、捕获电子碰撞和快速粒子不稳定驱动的动力学模型的基础上，研究了高n、环面Alfven本征模。低动能TAEs （KTAEs）在接近无碰撞极限时不存在。与TAEs一样，由于无耗散极限下的热离子有限拉莫尔半径效应，KTAEs的上端也存在。耗散对TAEs和上部KTAEs稳定性的影响可以用微扰的方法来处理。然而，由于其在气球空间中的扩展模式结构，即使具有大的快速粒子自由能，上层KTAEs通常也保持稳定或弱不稳定。另一方面，tae可能具有很强的不稳定性。当快速粒子驱动显著增大时，可以激发出一种新的谐振式TAE （RTAE）。RTAE是一种类束模式，其频率主要由波粒共振条件决定。RTAE的频率可以比TAE间隙频率小得多，可以解释为DIII-D实验中观察到的BAE。随着等离子体β的增加，TAE、RTAE和动力学气球模式强耦合；TAE变为RTAE，并最终连接到动力气球模式。给出了RTAEs和KTAEs稳定性的数值结果和解析分析，并与TAE稳定性进行了比较
High-n, toroidal Alfven eigenmodes (TAEs) are studied on the basis of a kinetic model that includes full thermal ion finite Larmor radius effects, trapped electron collisions and fast particle instability drive. Lower kinetic TAEs (KTAEs) are shown to be non-existent in the nearly collisionless limit. Like TAEs, upper KTAEs are shown to exist because of thermal ion finite Larmor radius effects in the dissipationless limit. Dissipation effects on the stability of both TAEs and upper KTAEs can be treated perturbatively. However, owing to their extended mode structure in the ballooning space, upper KTAEs usually remain stable or weakly unstable even with large fast particle free energy. On the other hand, TAEs can be strongly destabilized. A new resonant TAE (RTAE) can be excited when the fast particle drive is significantly large. The RTAE is a beam-like mode, with its frequency determined mainly by the wave-particle resonance condition. The frequency of the RTAE can be much less than the TAE gap frequency and may be interpreted as the BAE observed in DIII-D experiments. As plasma beta increases, the TAE, RTAE and kinetic ballooning modes strongly couple; the TAE changes into the RTAE and eventually connects to the kinetic ballooning mode. Numerical results and analytical analysis on the stability of the RTAEs and KTAEs will be presented and compared with the TAE stability