Drift and Diffusion of Electrons in an Atomic Gas between Closely Spaced Electrodes. II. Effect of Inelastic Collisions

Abstract

Previously derived source functions and generalized electron absorption coefficients are employed in a new method to obtain the electron flux in an atomic gas between closely spaced electrodes taking into account inelastic collisions. Energy losses due to elastic collisions are assumed to be relatively unimportant compared with inelastic collisions. The initial energy of the electrons at the source and the applied electric field are assumed to be insufficiently large to produce more than one inelastic collision for any electron, but otherwise there is no restriction on the number of inelastic thresholds. Given these restrictions it is shown that the results obtained are consistent with the usual two-term approximation to the Boltzmann equation. It is further demonstrated that the electrodes have little effect on the electron flux when the generalized electron absorption coefficients are dominated by electron-atom collisions. Conditions under which inelastic collisions have a significant effect on the electron flux are derived. Finally, the connection between the present steady state analysis and quantities obtainable by a pulsed electron source experiment are discussed.