The relation between the charge transported and number of photons emitted in partial discharges on dielectric surfaces

Abstract

Two-dimensional measurements were performed of the relation between the charge transported and number of photons emitted, accompanying discharges in air at the surface of a dielectric. The creep discharges were analysed for opaque dielectrics placed in an AC field of v=50 Hz and intensity of 103 V mm-1. A linear relation was found to exist between the number of photons and the charge, Nph= kappa Q, the coefficient kappa varying with the polarity of the electrode at which the discharges occurred, kappa +/ kappa -=0.5-0.8. It is postulated that the difference in kappa + and kappa - is due to the different average energy of electrons giving the discharge channel.