Boundary-induced effect on the spoke-like activity in E × B plasma
Boundary-induced effect on the spoke-like activity in E × B plasma
复制标题
E × B 等离子体中辐条状活动的边界诱导效应
DOI：
10.1063/1.5092702
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发表时间：
2019
影响因子：
2.2
通讯作者：
A. Smolyakov
中科院分区：
文献类型：
--
作者：
Eduardo Rodriguez;Valentin Skoutnev;Y. Raitses;A. Powis;I. Kaganovich;A. Smolyakov
在E × B潘宁放电中，辐条不稳定性受到与B场线垂直的边界的强烈影响。当被介质壁包围时，不稳定性最强。有了导电壁，偏压收集来自等离子体的电子电流，辐条变得更快，不那么相干，并且定位在更靠近轴的地方。相应的异常跨场输运是通过同时测量等离子体电位和密度来评估的。这表明介电壁的电子交叉场电流具有明显的大尺度E × B异常特征，达到放电电流的40%-100%，有效霍尔参数为βeff ~ 10。异常电流在导电边界处（表征为βeff ~ 102）大大减小。这些实验测量结果与E场的减少在质量上是一致的，从而引发了无碰撞的Simon-Hoh不稳定性。在E × B潘宁放电中，辐条不稳定性受到与B场线垂直的边界的强烈影响。当被介质壁包围时，不稳定性最强。有了导电壁，偏压收集来自等离子体的电子电流，辐条变得更快，不那么相干，并且定位在更靠近轴的地方。相应的异常跨场输运是通过同时测量等离子体电位和密度来评估的。这表明介电壁的电子交叉场电流具有明显的大尺度E × B异常特征，达到放电电流的40%-100%，有效霍尔参数为βeff ~ 10。异常电流在导电边界处（表征为βeff ~ 102）大大减小。这些实验测量结果与E场的减少在质量上是一致的，从而引发了无碰撞的Simon-Hoh不稳定性。
The spoke instability in an E × B Penning discharge is shown to be strongly affected by the boundary that is perpendicular to B field lines. The instability is the strongest when bounded by dielectric walls. With a conducting wall, biased to collect electron current from the plasma, the spoke becomes faster, less coherent, and localized closer to the axis. The corresponding anomalous cross-field transport is assessed via simultaneous time-resolved measurements of plasma potential and density. This shows a dominant large-scale E × B anomalous character of the electron cross-field current for dielectric walls reaching 40%–100% of the discharge current, with an effective Hall parameter βeff ∼ 10. The anomalous current is greatly reduced with the conducting boundary (characterized by βeff ∼ 102). These experimental measurements are shown to be qualitatively consistent with the decrease in the E field that triggers the collisionless Simon-Hoh instability.The spoke instability in an E × B Penning discharge is shown to be strongly affected by the boundary that is perpendicular to B field lines. The instability is the strongest when bounded by dielectric walls. With a conducting wall, biased to collect electron current from the plasma, the spoke becomes faster, less coherent, and localized closer to the axis. The corresponding anomalous cross-field transport is assessed via simultaneous time-resolved measurements of plasma potential and density. This shows a dominant large-scale E × B anomalous character of the electron cross-field current for dielectric walls reaching 40%–100% of the discharge current, with an effective Hall parameter βeff ∼ 10. The anomalous current is greatly reduced with the conducting boundary (characterized by βeff ∼ 102). These experimental measurements are shown to be qualitatively consistent with the decrease in the E field that triggers the collisionless Simon-Hoh instability.