The Influence of Diffusion on the Townsend Discharge in a Uniform Electric Field

Abstract

An analysis is presented to elucidate the role of diffusion in a Townsend discharge between plane parallel electrodes. Spatial independence of the electron energy distribution function is postulated, and the development proceeds by solution of the appropriate continuity equations. It is shown that experiment may be expected to verify Townsend's law in all but extreme cases, but that diffusion corrections must be applied if measured values of the primary ionization coefficient exT are to be used for etermination of quantities such as the ionizing collision frequency. Further, Paschen's law is emonstrated to be unaffected by effects resulting from diffusion.