Spatial distributions of electron density and electric field in discharges sustained within microwave circuits

Abstract

Overcritical density discharges sustained in cylindrical vessels placed within microwave circuits (e.g. cavities, waveguides) and controlled by diffusion are theoretically investigated. In such discharges, the mutual interaction between the plasma and the microwave electric field leads to a redistribution of the imposed (plasma-free) field. The authors predict the resulting spatial distributions of electron density and electric field. In the common case where the length of the active zone exceeds at least a few times its diameter, it is found that (1) the electron density and the electric field tend to be axially uniform and (2) the maintenance field intensity is the same as in an underdense discharge.