Electron Energy Distributions in Stationary Discharges

Calculations of the electron distribution function are presented for some simple examples of a stationary discharge in a dc space charge field. The treatment is valid when the predominant mechanism of energy exchange arises from motion in the dc space charge field. The computations indicate that the effect of dc space charge is, for a given external field strength, to increase the proportion of high energy electrons over that computed neglecting space charge. This results in a larger specific ionization rate, but the effect is not so great as to account for the low maintenance potentials observed in positive columns and in microwave discharges in inert gases.