Macrokinetic theory of electrons in gases

A closed, macroscopic description of the dynamics of an assembly of electrons under the influence of a space-time-varying field is presented. This is accomplished by approximating the phase-space distribution function in an equivalent space whose coordinates are the infinite set of moments, {${\mathit{m}}_{\mathit{j}}$;j=1,...,∞}. An attempt has been made to formulate a rigorous procedure for obtaining approximate distributions with varying degrees of space-time resolution and for establishing their range of validity. Expressions are presented for the approximate distribution function and the transport parameters with resolution corresponding to the scale for energy relaxation.