电子回旋共振加热影响托卡马克等离子体芯部环向转动的理论研究

Plasma rotation plays an important role in reducing microscopic turbulence and transport and in stabilizing macroscopic magnetohydrodynamic instability, and so is relevant to confinement of magnetic fusion plasmas. Paticularly, spontaneous rotation (without external momentum input) is a topic of intense interest. Recently, counter-current toroidal rotation induced by electron cyclotron resonance heating (ECRH) is found in the core regime of international and domestic magnetic confinement fusion devices. However, the physical mechanism is not very clear yet. This project plans to investigate the toroidal rotation in both ITG and TEM turbulence by using gyrokientic theory. Here, we will focus on turbulent acceleration which is not considered in previous works. It can not be written as a divergence of Renolds stress, and is a source/sink of toroidal rotation. By combining turbulent acceleratin and residual stress, we will investigate their effects on toroidal rotation by including residual stress. Then, we will explore the physical mechanism of effects of ECRH on core toroidal rotation by comparing our theoretical results with the experimental observations before/after turning on ECRH.This study could develop existing generation theory of spontaneous rotation, and provide theory foundations for predictions of plasma rotation and confinement in future ITER.

等离子体转动对于抑制微观湍流和输运以及宏观磁流体不稳定性起着重要作用，所以与磁约束聚变等离子体的约束性能密切相关。特别是自发转动，即没有外界动量注入情况下等离子体自发产生的转动，是当前的研究热点。最近，国际和国内的磁约束聚变装置上都发现电子回旋共振加热（ECRH）在芯部引起与电流方向相反的环向转动，但是其物理机制还不十分清楚。本课题拟采用回旋动理学方法，对比研究离子温度梯度（ITG）模和捕获电子模（TEM）湍流中的环向转动。其中，我们将重点关注以往转动研究中没有考虑过的湍动加速项，它不能写成雷诺张量的散度，是平均环向转动的源/汇。我们将结合残余张量和湍动加速，研究它们对环向转动的影响。然后，把理论结果与ECRH启动前后的实验观测相结合，探索ECRH影响芯部等离子体环向转动的物理机制。这一课题的展开可能发展已有的自发转动产生的理论，为将来ITER等离子体转动和约束性能的预测提供理论基础。

等离子体转动对于抑制微观湍流和输运以及宏观磁流体不稳定性起着重要作用，所以与磁约束聚变等离子体的约束性能密切相关。在将来的 ITER 装置上，中性束注入很可能不足以提供需要的外部转动驱动，因此，研究自发转动对于ITER装置十分必要。我们的研究内容围绕自发转动展开，取得的主要进展有：（1）提出湍动加速驱动自发转动的新机制，并对比研究静电ITG和CTEM湍流中的自发转动，针对ECRH使芯部同电流环向转动降低的实验现象给出理论解释；（2）研究台基区顶部电磁ITG湍流驱动的自发转动，并针对DIII-D的实验参数估算了各项自发转动驱动的大小；（3）证明了湍动加速机制与动量守恒不矛盾，从根本上解除了人们对湍动加速的疑虑；（4）发展了湍流动量输运（包括平行方向和极向）的非线性理论。这些工作为自发转动有关的实验现象提供了理论解释，解决了人们对湍动加速机制与动量守恒自洽性的疑问，为将来例如ITER装置高参数运行条件下自发转动的预测提供了理论参考依据。