Observation of vertical charge-separation current in an electron-cyclotron-heated toroidal plasma
Observation of vertical charge-separation current in an electron-cyclotron-heated toroidal plasma
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DOI：
10.1088/0741-3335/52/6/065011
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发表时间：
2010-06
影响因子：
2.2
通讯作者：
S. Nishi;T. Sakabe;M. Uchida;H. Tanaka;T. Maekawa
中科院分区：
文献类型：
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作者：
S. Nishi;T. Sakabe;M. Uchida;H. Tanaka;T. Maekawa
假设轴对称环面等离子体浸没在（R， ϕ， Z）柱坐标的环面磁场bφ中，Z坐标在对称轴上。由于场梯度和速度曲率，电子向下漂移，而离子向上漂移。据推测，到达底壁的电子通过导电容器流到顶部，在那里它们与离子重新结合，从而完成了垂直电荷分离电流的闭合回路。低纵横比环面实验装置（Low Aspect ratio Torus Experiment， LATE）中新制造的电流收集电极首次直接测量了在电子回旋加速器频率范围内由微波功率维持的等离子体。电流的大小与上述电子的垂直漂移模型是一致的。在微波注入过程中，当人为插入大电阻阻塞电流电路时，放电迅速终止。
Suppose an axisymmetric toroidal plasma is immersed in a toroidal magnetic field Bϕ in the cylindrical coordinates of (R, ϕ, Z) with Z coordinate on the symmetric axis. The electrons drift downward while the ions drift upward due to the field gradient and curvature by the velocity, . It was conjectured that the electrons that reached the bottom wall flowed through the conducting vessel to the top where they recombined with the ions, thus a closed circuit being completed for the vertical charge-separation current. This current has for the first time been directly measured by current-collecting electrodes newly fabricated in the Low Aspect ratio Torus Experiment (LATE) device for a plasma maintained by a microwave power at the electron cyclotron range of frequency. The amount of current is found to be consistent with the above vertical drift model for electrons. The discharge terminates quickly during microwave injection when the current circuit is blocked by the artificial insertion of a large resistance.