THE DISTRIBUTION OF ELECTRONS IN A UNIFORM ELECTRIC-FIELD

Experiments are under way at the University of New England to measure the optical absorption of excited gas particles in a pre-breakdown dis charge. Such measurements can be used to deduce the number density of electrons in the discharge. By comparing this experimental density map with the predictions of theory, electron transport parameters may be determined. In this paper, new theoretical expressions are derived for the number density distributions of electrons in a uniform electric f ield. These are found by solving the electron diffusion equation in a plane parallel electrode geometry with a radially symmetric cathodic c urrent source. The contribution of ion-induced secondary current is in cluded, and problems posed by non-equilibrium conditions near the elec trodes are addressed. Techniques of data reduction are discussed with a particular emphasis on the avoidance of these problems.