Monte Carlo simulation of electrons in the cathode region of the glow discharge in helium

Abstract

In the cathode fall region of a glow discharge, where the electric field decreases rapidly with distance from the cathode, parameters for electrons obtained in an equilibrium state can not be correctly used in a theoretical study. In this paper, the cathode region in a normal glow discharge has been analysed by a Monte Carlo simulation. Four types of inelastic collisions together with an elastic collision, the reflection of electrons from electrodes and the back-scattering of electrons to the cathode, were taken into account considering the three-dimensional motions of electrons. Results show that alpha /p (where alpha is the ionisation coefficient and p is the gas pressure) is in good agreement with Friedland's result. Also, the mean energy of electrons in the negative glow region was found to be about 11 eV, which is much smaller than previous values. The difference in spatial distribution of optical emission between singlet terms and triplets was also indicated.