Electron distribution function relaxation in monatomic gases

The authors discuss an analytic solution of the Boltzmann equation which describes the relaxation in time of the electron distribution function for electrons in a plasma derived from the monatomic gases He, Ne, Ar, and Xe. It is assumed that there are no perturbing forces on the electrons and that at t=0 they have a Maxwellian distribution function corresponding to an average energy of 2 eV. The electrons then lose energy through elastic collisions with neutrals and eventually energy-equilibrate with the neutrals, which are assumed to be cold. The evolution of the electron distribution function in time and velocity space is calculated for each gas. This model is approximately correct for the afterglow period of an electrical discharge in a monatomic gas. It is possible to calculate a time which is a measure of the decay time of the electron energy in an afterglow plasma