The space charge due to corona

A new technique for measuring the field strength and deducing the ion density about a wire in corona is needed. One such new method is measurement of a-c corona directly with a crystal galvanometer connected between two probe screens. The net space charge density was derived from the field strength curves in a single mathematical step, using Poisson´s equation. The amount of charge present may be shown quantitatively by using a special function of the charge density. This is the total net charge contained in a cylindrical shell, one centimeter long, one centimeter thick, and of a parametric radius R. This total net charge is designated by Q. It is a convenient notation, for Q does not vary as a cloud of ions moves radially, but can change only by diffusion, recombination, or the introduction of new ions.