大尺度磁分散电弧等离子体位形的静电探针诊断

Electric-probe Diagnostics for Plasma Configuration of Large-scale Magnetically Dispersed Arc Plasma

磁旋转电弧可以产生大面积均匀等离子体:磁分散电弧等离子体。利用快速移动水冷静电探针对大气压氩弧磁分散电弧等离子体进行了诊断,得到发生器弧室内的电子温度分布、电弧位形以及等离子体波动等信息。诊断结果表明:等离子体弧柱区呈圆盘状,并在轴向有较大扩张,弧柱区下游等离子体波动较大,为等离子体云与冷气团混合所致。将探针诊断结果与采用热力学平衡模型的数值计算结果比较,发现2者具有相似的等离子体位形,但实验测量得到的电子温度更高,等离子体分布范围更广。分析认为,这种差异可能是等离子体偏离局域热力学平衡和等离子体的不稳定性造成的。

Magnetically rotating arc can induce large-scale magnetically dispersed arc plasma.Using a fast-moving water-cooling electric probe,we diagnosed large-scale dispersed arc plasma in argon at atmospheric pressure,and obtained its electron temperature profile,arc plasma configuration and plasma fluctuation.It is shown that the arc column exhibits a disk configuration and expands in axial direction.In the meantime,the erratic fluctuation increases in the plasma downstream,which may be a result of the cold air entrainment in the plasma cloud.There is a good comparability in plasma configuration between the measurements and the simulations by local-thermedynamic-equilibrium magneto-hydrodynamic model,while the measurements have relatively higher electron temperature and larger plasma volume phenomenon.Further analysis indicates that the difference may be caused by deviation from thermal equilibrium of plasma and instability of plasma.