Nonlinearity: Basis for self-consistent modeling of surface wave produced plasmas in diffusion controlled regimes

Abstract

A fluid model of surface wave produced discharges is presented for diffusion controlled regimes taking into account simultaneously nonlinear contributions from stepwise ionization and volume recombination. The saturation of metastable densities with growing electron density reduces the effect of step ionization and allows recombination to become effective toward high electron densities. The charged particle continuity and energy balance equations linking electron density and electric field intensity yield the plasma permittivity under conditions of strong ionization nonlinearity. This permittivity is valid for high frequency discharges in general. In the second part of the modeling this nonlinear permittivity is introduced into the electrodynamical relations for discharges maintained by the field of traveling surface waves, and subsequently the self-consistent behavior of plasma and wave characteristics along the discharge length is calculated. Both the main part of the discharge column produced by Joule heating in the plasma volume and the end section of the discharge, where the mechanism of resonance absorption of the wave power close to the tube wall can sustain the discharge, are considered.