Distribution of electrons and ions in a corona discharge

Abstract

A new method of computing the distribution of electrons and ions in the spacecharge field of corona is described. For any point in a coaxial cylindrical geometry the resultant current density is well known because of the symmetry conditions. The proportion of electrons, and positive and negative ions in the current density, however, can be determined only by calculation of the ionisation and attachment processes. Since the coefficients for these processes are nonlinear functions of the local field strength, and the field strength in turn depends on the spatial distribution of electrons and ions, an iterative method of computing has been developed. The basically different distributions of electrons and of ions for positive and negative polarity determined by this method are helpful in explaining the underlying physical phenomena. The calculated results show very good agreement with measurements from the literature, where the radius of the visible corona glow and the particle-charging in the proximity of the corona wire had been examined.