Point-to-plane corona: Current-voltage characteristics for positive and negative polarity with evidence of an electronic component

Abstract

A series of measurements carried out with the point-to-plane symmetry has shown that positive corona confirms the Townsend relation while for the negative corona this happens only at large point-to-plane distances (greater than 1.5 cm). In this case, the ratio of the prefactors in Townsend relation, for the same geometry, approaches the expected constant (the ratio of the mobilities) at larger distances, around 6 cm. For distances below 1.5 cm, the square root of the current is linear with the voltage, with an intercept of ∼1.4 kV. The results are interpreted as giving evidence of an electronic component at small distances, as suggested by Sigmond. The characteristics change to Townsend at higher distances when the electronic component becomes small as compared with the ionic one.