The 3D numerical simulation of a transient vacuum arc under realistic spatial AMF profiles

Based on a transient and three-dimensional (3D) finite-volume model developed for diffuse vacuum arcs with external axial magnetic field (AMF), we analyse the characteristics of a transient vacuum arc plasma under different spatial AMF distributions in the contact gap. In particular, we discuss the influence of spatial AMF profiles typically found in commercial vacuum interrupters upon quantities of interest such as arc voltage, energy densities onto the anode, electron and ion temperatures. The dependence of the AMF field on the instantaneous current is explicitly taken into account as a function of time. The simulation results document that the distributions of current density and ion mass flow rate at the cathode have a significant effect on the quantities of the vacuum arc plasma, for example the density of the energy flux transported to the anode.