A new method to study processes of corona charging and electric relaxation in electrets

The idea of the proposed method is in the analysis of the experimentally obtained response (electret potential) of the dielectric sample on application of the rectangular current pulses of infra-low frequency. The current is supplied by a corona, and the whole process of the poling (electrization) splits into a number of separate fractions, each consisting of the stage of the potential growth under the constant charging current and the stage of the potential decay in the gap between the two adjacent current pulses. The corresponding formulae are derived allowing to follow the dynamics of the dielectric constant and the apparent conductivity with evolution of the poling process. The method is applied to study corona charging and electric relaxation in PVDF, although it is applicable in principle to any dielectric with a reasonable apparent conductivity