用磁探针反演磁岛二维结构的方法及其在HL-2A装置上的应用

The method of inversion of magnetic island two-dimensional structure by magnetic probes and its application on HL-2A tokamak

介绍了HL-2A装置中利用磁探针数据反演磁岛极向二维结构的新方法,以及在反演基础上建立的撕裂模动态分析方法。在实验中通过磁探针测量确定作为扰动磁场来源的扰动电流。将扰动磁通与由EFIT重建的平衡磁通叠加反演出磁岛的结构,并给出磁岛的宽度。然后,按时间顺序建构二维结构图并依次记录,之后依次展现图像就可以对磁岛进行动态分析。应用此方法进行撕裂模分析,得出了磁岛旋转与电子抗磁漂移方向相同,验证了磁岛宽度与扰动场的关系及ECRH对磁岛的抑制作用。这显示了磁探针反演磁岛结构方法的直观性,对观察并控制MHD不稳定性非常有利。

The new method that reconstructs the polar two-dimensional structure of the magnetic island using magnetic pickup coils data is introduced on HL-2A tokamak and dynamic analysis method that set up based on it for tearing mode is also introduced.In this experiment,the perturbation current which is the source of the perturbation magnetic field can be determined using the data measured by magnetic probes.Superimposing the perturbation flux and equilibrium flux reconnected by EFIT,the structure and the width of the magnetic islands can be obtained.Then two-dimensional structure maps are set up chronologically and recorded in turn.After that these maps are revealed in turn and magnetic island can be analyzed dynamically.This method is applied to analyzing tearing mode.The conclusion that magnetic island rotating direction is in accordance with electronic diamagnetic drift direction is reached.The relationship between the magnetic island width and the magnetic perturbation field is proved and the suppression of magnetic island by ECRH is also verified.It shows the immediacy of the method of inversion of magnetic island structure by magnetic probes and it is very useful for watching and controlling MHD instability.