轴向磁场中电弧螺旋不稳定性的简化数值分析

A simplified numerical analysis of helical instabilities of arcs in axial magnetic field

在静电近似下 ,通过数量级的分析 ,简化了能量方程。用数值方法研究了外加轴向磁场、电流分布、弧电流等对电弧螺旋不稳定性的影响。数值结果表明 ,在具有外加磁场情况下 ,当弧柱内均匀电流分布时 ,正向磁场能够使短波长的扰动稳定 ,反向磁场能够使长波长的扰动稳定。当弧柱内电流为抛物线形分布时 ,外加正向磁场对于短波情况下的稳定性影响很小 ,但对于长波情况 ,稳定性增强 ;外加反向磁场 ,同样能稳定中等和长波情况下的电弧。

The energy equations were simplified by the correct electrostatic ordering under electrostatic approximation. The effects of the external axial magnetic field, the current profiles and arc currents on the helical instabilities of arcs were studied by using numerical method. In the presence of the external magnetic field, numerical results show that when the current profile of an arc column is the uniform distribution, the short wavelength perturbation can be stabilized by positive direction magnetic field, whereas the long wavelength perturbation can be stabilized by reverse magnetic field. When the current profile of an arc column has a parabolic distribution, in the short wavelength perturbation case, the effect of positive direction magnetic field on the arc stability is very small. However, its stabilizing effect is enhanced for the long wavelength perturbation. The intermediate and long wavelength perturbations can also be stabilized by reverse magnetic field.