KTX反场箍缩装置中等离子体小破裂现象研究

在科大反场箍缩磁约束实验装置(KTX)实验中，观测并研究等离子体的显著位移及其带来的小破裂现象。通过分析H_α 谱线、软X 射线辐射以及磁探针数据，发现其主要特征是破裂前等离子体电流重心的缓慢外移，在小破裂后等离子体电流重心在百微秒时间迅速反向移动，重新达到稳定位形。同时，等离子体小破裂伴随着m=1 的边界磁场扰动、稳定壳上显著变化的涡流、以及H_α 谱线和软X 射线辐射的增强。通过对KTX 小破裂实验数据的分析与统计，得出回弹位移与等离子体位移成线性关系。对等离子体电流分布及稳定壳涡流，建立了唯象电路模型，得出了和实验相一致的结论，确定了稳定壳上快速变化的涡流是等离子体小破裂后回复平衡的重要因素。

Research on minor disruptions in Keda torus experiment

In experiments of Keda torus experiment (KTX), a reversed field pinch magnetic confinement device, significant plasma displacement and the following minor disruption phenomenon were observed and studied. Its main feature is the slow outward plasma displacement before the minor disruption and rapid moving backward in a hundred microseconds after the minor disruption, reaching a stable configuration again, indicating by the data of the hydrogen-α spectrum, soft X-ray radiation and magnetic probe. At the same time, the minor disruption is accompanied by the disturbance of the m=1 boundary magnetic field, the rapid variation of the eddy currents on the stabilization shell, and the enhancement of the hydrogen-α spectrum and soft X-ray radiation. Based on the analysis and statistics of KTX minor disruption experimental data, the linear relationship between rebound displacement and plasma displacement is obtained. In this paper, a phenomenological circuit model is established for plasma current distribution and stable shell eddy currents, and the conclusion is consistent with the experimental results. It is determined that the rapidly changing eddy current on the stable shell is an important factor for restoring equilibrium after a minor disruption.