Heavy-Particle Hybrid Simulation of a High-Voltage Glow Discharge in Helium

Abstract

A high-voltage glow discharge – operated at several thousand Volts – is described by a hybrid model in which we apply kinetic simulation for the fast electrons and fast heavy particles (He+ ions and neutral atoms). In the model we take into account the increase of the gas temperature, and calculate the apparent secondary electron yield at the cathode from the flux-energy distributions of heavy particles. The results of the simulations show that electron production at the cathode is dominated by the impact of fast neutral atoms (ejecting ≈75% of the primary electrons) and that ionization of the gas atoms by fast heavy particles contributes significantly to the ionization balance of the discharge. A fair agreement is obtained between measured and calculated electrical characteristics and potential distributions, and the calculations confirm the existence of the high-energy electron beam observed experimentally.