Theoretical Computations of the Effects of the Metastable Populations on Electron Energy Balance and Distribution Function in a Helium Afterglow

The electron temperatures and the electron energy distribution function in a helium afterglow, for pressures of 10-80 Torr and electron densities of ${10}^{11}$-${10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$, are calculated by a technique which readily allows the determination of the relaxation processes controlling the energy input into the electron gas. Comparisons are made to existing experimental data. The energy-distribution-function evaluations show that careful consideration of this parameter must be made, for it can be extremely non-Maxwellian.