The internal magnetic structure and current drive in the SPHEX spheromak
The internal magnetic structure and current drive in the SPHEX spheromak
复制标题
SPHEX spheromak 的内部磁性结构和电流驱动
DOI：
--
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
K. Gibson
中科院分区：
文献类型：
--
作者：
D. M. Willett;P. Browning;S. Woodruff;K. Gibson
在SPHEX球形标记器上实现了螺旋注入稳态电流驱动。为了了解等离子体环向电流在闭合磁通上驱动的过程，首先需要对内部磁场和电流结构进行诊断。描述了一种将无力平衡拟合到线性可插入探针磁场数据的方法。结果表明，虽然内部电流分布的详细形状对数据中的小误差和拟合函数的选择很敏感，但总体场结构和相关的全局参数可以很好地拟合。电流驱动过程与环面模态数n = 1的波动密切相关。当n = 1模式为偶发性模式时，我们详细研究了Ti吸波拍摄，表明在单次拍摄中，电流驱动机制在一段时间内被打开和关闭，对应于模式的存在或不存在。这提供了明确的证据，表明n = 1模式负责当前驱动器。
Steady-state current drive by helicity injection has been demonstrated in the SPHEX spheromak. In order to understand the processes by which plasma toroidal current is driven on the closed flux, it is necessary first to diagnose the internal magnetic field and current structure. A method is described which fits force-free equilibria to magnetic field data from a linear insertable probe. It is shown that the overall field configuration and associated global parameters can be well fitted, though the detailed shape of the internal current profile is sensitive to small errors in the data and the choice of fitting function. The current drive process is closely associated with fluctuations having toroidal mode number n = 1. We investigate in detail shots with Ti gettering, when the n = 1 mode is episodic, showing that the current drive mechanism is switched on and off for periods during a single shot, corresponding to the presence or absence of the mode. This provides definitive evidence that the n = 1 mode is responsible for the current drive.