Hollow cathode glow discharge in He: Monte Carlo–Fluid model combined with a transport model for the metastable atoms

Abstract

A hollow cathode discharge (HCD) in He is studied based on a Monte Carlo–fluid hybrid model combined with a transport model for metastable He atoms. The Monte Carlo model describes the movement of fast electrons as particles, while in the fluid model, the slow electrons and positive ions are treated as a continuum. The continuity equations are solved together with the Poisson equation in order to obtain a self-consistent electric field. The He metastable transport model considers various production and loss mechanisms for He metastable atoms. These three models are run iteratively until convergence is reached. Typical results are, among others, the excitation and ionization rates, the electron, ion, and metastable densities and fluxes, the electric field, and potential distribution. The relative importance of different processes determining the metastable density in a He HCD is analyzed, as well as the role of He metastable atoms and He ions on the secondary electron emission at the cathode. Calculation results are compared with experimental data for the same discharge conditions, and good agreement was obtained.