The Mechanism of the Negative Point to Plane Corona Near Onset

TLDR

Oscillographic studies of negative point‑to‑plane coronas in air reveal that the discharge’s periodicity arises from space‑charge formation and subsequent clearing by the electrostatic field. The oscillograms show that the negative corona current consists of discrete pulses whose magnitude and frequency are linked to the corona current, point size, and gas pressure, and that pulse frequency is independent of gap length and unaffected by external circuit constants.

Abstract

Oscillographic studies have been made of the currents in negative point to plane coronas in air. The oscillograms obtained indicate that the negative corona current is composed of discrete pulses whose magnitude and frequency have a definite relationship to the corona current, point size and gas pressure. The frequency of the current pulses appears to be independent of gap length under the experimental conditions studied. The frequency of the oscillations does not appear to be affected by changes in the electrical constants of the discharge circuit outside the gap. The periodic character of the discharge seems to derive logically from space charge formation in the gap and subsequent clearing under the action of the electrostatic field.