Fast Time Analysis of Intermittent Point-to-Plane Corona in Air I. The Positive Point Burst Pulse Corona

Abstract

Techniques for fast oscilloscopic analysis of intermittent point‐to‐plane coronas in air are described. Such analysis shows the positive point burst pulse corona to consist of an initial pulse followed by secondary pulses at varying time intervals. The duration of both pulses is less than 10−7 second, the initial pulses having from 1 to 2×107 ions and the secondaries from 1 to 5×106 ions depending on the voltage. Time intervals between pulses range from the clearing time of ions across the gap (milliseconds) to random intervals as short as 2 microseconds for secondary pulses well above threshold. Thus, in analogy to Geiger counter terminology dead times run from 2 microseconds up, and clearing times are in the order of milliseconds corresponding to local clearing of space charge near the point for secondaries, and removal of massive space charge from the low field region of the gap. A complete sequence of events from threshold to steady corona is analyzed, and indicates the predominance of self‐counting through negative ion formation in air.