Relaxation of surface charge

An analysis of the time decay of the surface charge on an insulator resting on an earthed plate is made in terms of the internal field and the spatial distribution of volume charge. It is shown that Davies' analysis (see abstr. A29860 of 1967), is valid for terms shorter than a charge transit time and full solutions are obtained for the zero external field (Kelvin) case. The analysis is based on a transformation of the field equation governing charge transport into an equivalent heat transport formalism and it is shown that this transformation may have general applicability in surface and volume charge problems.