鱼骨模对EAST混杂放电模式芯部输运的影响机理研究

Fishbone instability is due to an interaction between the energetic particles and an m/n=1/1 MHD perturbation. At present, most of the studies on the fishbone instability are focused on the mode and stability analysis, but few on the interaction between the fishbone instability and the transport process. In EAST high normalized beta experiments (hybrid scenario), the improvement of core confinement accompanied with fishbone instability was observed, which provided a good experimental platform for the study of the interaction between fishbone instability and transport process. In order to understand the physical mechanism of the effect of fishbone instability on core transport, this project plans to study the interaction between the fishbone instability and the core confinement improvement by experimental analysis and simulation, transport code TGYRO and global kinetic-MHD hybrid code M3D-K will be used in the simulation. Combined with experiment observations, we will study the experimental conditions of the fishbone instability excitation in the core region and its effect on the redistribution of energetic ions and toroidal current density. we will also study its influence on the radial transport, including the transport on particles and energy channels. Understand the relevant physical mechanism in the process of these multi-scale interactions, propose theoretical simulation and prediction so as to achieve higher parameters and longer pulses in the hybrid operation scenario experiment.

鱼骨模是由高能粒子与模数为m/n=1/1的MHD磁流体扰动相互作用激发的一种磁流体不稳定性。目前对鱼骨模的研究大多集中在模式及稳定性分析上面，而对其与输运过程的相互作用研究则很少。在EAST高归一化比压实验中（混杂放电模式）观察到芯部约束改善行为伴随着鱼骨模的出现，这为研究鱼骨模与输运相互作用过程提供了良好的实验平台。为了理解鱼骨模对芯部输运影响的物理机理，本项目拟采用实验分析与模拟相结合的方式，模拟方面主要采用输运程序TGYRO及动理学-磁流体混合程序M3D-K等程序，紧密结合EAST混杂运行模式实验，研究鱼骨模与芯部约束改善的相互作用关系。主要内容包括：研究芯部位置鱼骨模被激发的实验条件及激发后对高能离子再分布和电流分布的影响；研究其对径向输运的影响，包括对粒子及能量通道的输运影响；深入理解这些多尺度相互作用过程中的相关物理机理，为如何在实验中达到更高参数更长脉冲的混杂运行模式提出理论模拟参考和预测。

在EAST高归一化比压实验中（混杂放电模式）观察到芯部约束改善行为伴随着鱼骨模的出现，为研究鱼骨模与输运相互作用过程提供了良好的实验平台。本项目采用了实验分析与模拟相结合的方式，对EAST混杂运行模式中实验数据库进行了总结，确认了鱼骨模和内部输运垒之间的关联及相应的实验条件；研究了鱼骨模频率的特征，高能粒子比压与鱼骨模循环频率的关系；对内部输运垒的特征参数进行了统计，获得了不同通道下输运垒的特征参数及实现的实验条件。研究了鱼骨模对径向输运的影响机理及与q分布之间的关系，鱼骨模不稳定性会产生一个局部的径向电场，这个径向电场可以跟磁场产生一个EⅹB的剪切，从而诱发内部输运垒的产生。对EAST上实现更高参数、更靠外的内部输运垒进行了模拟预测。