Modelling of large-scale microwave plasma sources

Abstract

Theoretical models have been developed for large-scale microwave discharges driven by surface waves which account in a self-consistent way for the main plasma balances, including bulk and surface elementary processes, as well as wave electrodynamics. The systems under consideration are long tubular and large-volume, slot-antenna excited plasma sources. As an example of application, discharges in N2–Ar mixtures, which are characterized by a complex kinetics, are analysed in some detail. The approach used describes self-consistently the spatial structure of the plasma sources, i.e. the spatial distribution of population densities of excited species, charged particles and ground-state molecules and atoms taking into account the main energy exchange pathways as well as plasma–wall interactions. The model predictions are shown to compare well with experiment in the case of both sources. It is demonstrated that the self-consistent models developed provide deep physical insight into the discharge workings, being also instrumental as a tool for the optimization of these plasma sources in view of specific applications.