Local Field and Ballistic Electron Models for Low Pressure RF and DC Glow Discharges.

An accurate description of plasma structure, i.e. the spatial distributions of ion and electron densities and currents, is an essential ingredient for reliable simulations of plasma chemical processes. In this work, local field and ballistic electron models for dc glow discharges are tested by comparing calculated current-voltage characteristics, ion densities, and electric field reversals with experiment. In general the local field model, which assumes that ionization and transport coefficients are functions of only the local electric field, is in poor agreement with experimental results obtained from dc glows through Ar and Ar/N sub 2 mixtures. This is because the local-field assumption is invalid in the non-uniform, strong-field sheath region between the plasma and the electrode.