High-current vacuum arc under axial magnetic field: Numerical simulation and comparisons with experiments

Based on a magnetohydrodynamic model, a numerical simulation of high-current vacuum arc (HCVA) is carried out. In this model, the kinetic energy terms and ion viscosity terms in energy conservation equations are considered. Compared with the supersonic constricted vacuum arc, the ion flow in HCVA is in the subsonic status. Therefore, boundary conditions of cathode and anode sides have to be adjusted for HCVA. According to the simulation results of HCVA, we can find that the maximal plasma pressure appears near the cathode side. The characteristics of HCVA are significantly different from those of supersonic vacuum arc. Then, we make the comparisons between simulation results and experimental results (such as electron number density, electron temperature, ion temperature, high speed charge-coupled device photographs, and so on). The simulation results are in agreement with the experimental results. In addition, we also analyze the influence of different arc models on the distribution of current density in the anode side.