Numerical simulation of electrode erosion phenomenon in low pressure subnanosecond spark gaps

In this paper the effect of the electrode erosion on discharge mechanism in subnanosecond regime has been investigated. The equations of current density and temperature distribution in the cathode together with the equation of state of the cathode material have been simulated using appropriate boundary conditions given by emission mechanisms at the cathode surface for different electrode geometries and gas pressures. These simulations indicate that in case of very low pressures of less than 1 mbar and very inhomogeneous cathode geometries the explosive electron emission is the dominant breakdown mechanism.