Drift Velocity and Runaway Phenomena for Electrons in Neutral Gases

Abstract

Necessary conditions for the absence of "runaways" are presented for electrons moving in a neutral gas under the influence of a steady-state uniform electric field. Then, simple and clarifying concepts are presented relevant to the comparison between the usual expression of the drift velocity and a recent expression given in a preceding paper in the framework of a path-integral formalism. For a steady-state uniform situation, the equivalence of the two definitions, recently questioned, is proved in very general conditions. In the Appendix, critical comments are introduced concerning the treatment of path-integral methods in a well-known book.