A model of dc glow discharges with abnormal cathode fall

A model for an abnormal glow discharge, including a self-consistent analysis of the cathode fall, was developed. It combines microscopic particle simulation by means of Monte Carlo methods with a fluid model of the gas discharge. The model allows calculations of the steady-state electrical field distribution, the charged-particle densities, and the current densities along the axis of the discharge. The model was used to simulate a glow discharge in 80% He and 20% SF6 at a pressure of 8 Torr with a current density of 1 A/cm2. The computed discharge voltage agrees well with measured values. The computer code can easily be modified to describe the charged-particle densities and energies not only in the cathode fall region, but in any plasma boundary layer.