Improved Cathode Spot Crater Model in Vacuum Arc

Abstract

An improved two-dimensional (2D) rotary axisymmetric model based on our former work has been developed to describe the formation and development of cathode spot in vacuum arc. In current model, the hydrodynamic equations include plasma pressure, ion pressure, saturated vapor pressure and Lorentz force; the heat transfer equation include plasma energy flux density, thermo-field emitted electrons, backflow ion flux, back-diffused electrons, surface evaporation and Joule Heating. Artificial Parameters used in current model include electron temperature, near cathode voltage drop, average charge number, ion number density, which all come from experiments and other researchers' work. Cathode spot maintains 30ns and during this time, all artificial parameters are fixed. The composition of the current density is discussed in detail. The simulation results are in good agreement with the experimental results.