Modelling and application of a new method to measure the non-thermal electron current in the edge of magnetically confined plasma
Modelling and application of a new method to measure the non-thermal electron current in the edge of magnetically confined plasma
复制标题
磁约束等离子体边缘非热电子流测量新方法的建模与应用
DOI：
10.1088/1741-4326/ac2aba
复制
发表时间：
2021-09
期刊：
影响因子：
3.3
通讯作者：
Gao X.
中科院分区：
文献类型：
--
作者：
Liu S. C.;Liang Y.;Zhang H. X.;Yan N.;Liao L.;Zhang X. X.;Liu X. J.;Wei W. Y.;Zhao N.;Chen L.;Chen R.;Hu G. H.;Ming T. F.;Sun Y.;Qian J. P.;Zeng L.;Li G. Q.;Wang L.;Xu G. S.;Gong X. Z.;Gao X.
非热电子在托卡马克和仿星器的边缘等离子体中可以形成相当大的电流。提出了一种测量磁约束等离子体边缘非热电子流的新方法-定向电子探针法。DEP由两个相对的通道组成，其连接线与局部磁场线对齐。每个通道具有孔，该孔具有小的径向宽度和足够的厚度以由于其大的拉莫尔半径而阻挡高能离子，并且在孔的端部处，收集器被偏置到正电压以排斥低能离子。以这种方式，DEP的收集电流主要由电子贡献。基于Boris算法进行了粒子轨道仿真，验证了DEP算法的有效性和合理性。根据模拟结果，与电子收集概率相比，离子收集概率很小，因此收集电流主要由电子贡献。在麦克斯韦-玻尔兹曼分布下，从两个通道收集的热电子的电流几乎相等，并且净电流由非热电子驱动。径向阵列DEP已成功地应用于EAST的刮削层（SOL）非热电子流测量。在低杂波加热阶段观察到非热电子流的幅度和结构。实验结果与模拟结果进行了比较，揭示了SOL电流具有相同的径向结构，验证了DEP方法的有效性。
The non-thermal electrons could form considerable current in the edge plasma of tokamak and stellarator. A new method, named directional electron probe (DEP), is proposed to measure the edge non-thermal electron current in magnetically confined plasma. The DEP consists of two opposite channels whose connection line aligns with the local magnetic field line. Each channel has a hole with small radial width and enough thickness to block high energy ions due to their large Larmor radii, and at the end of the hole the collector is biased to positive voltage to repel low energy ions. In this way, the collected current of DEP is mainly contributed by electrons. A particle orbit simulation is performed based on the Boris algorithm, which demonstrates the validity and rationality of the DEP. According to the simulation, the ion collection probability is quite small if compared with the electron collection probability, consequently the collected current is mainly contributed by electrons. The collected currents of thermal electrons under Maxwell–Boltzmann distribution from both channels are almost equal, and the net current is driven by non-thermal electrons. A radial array of DEP has been successfully applied to the scrape-off layer (SOL) non-thermal electron current measurement in EAST. The amplitude and structure of the non-thermal electron current are observed during the lower hybrid wave heating phase. The experimental SOL net current is compared with the simulated net current from a rough estimation, revealing the same radial structure of SOL current and demonstrating the validity of DEP.