Numerical analysis of vacuum arc under nonuniformly distributed axial magnetic fields

A two-dimensional (2-D) magnetohydrodynamics (MHD) model of free expansion interelectrode plasma of vacuum arc is developed. The model is solved by numerical method and an iteration strategy with the position of free boundary (FB) taken into account. Under various radial distributions of axial magnetic field (AMF), uniform AMF, saddle shaped AMF, and bell shaped AMF, we got self-consistent results, by which we have studied the influence of radial AMF distribution on vacuum arc.