The effect of micro-gap discharge paths on ionization coefficients and similarity theory

Abstract

In order to investigate the impact of discharge paths at the micrometer scale on breakdown, two sets of different electrodes were arranged with electrode gaps ranging from 10 μm to 100 μm and gas pressures varying from 1 kPa to 100 kPa. The research has revealed that without an insulating layer at the edge of the electrode, when the product of gas pressure (p) and electrode gap (d) is less than 60Pa·cm, the number of positive ions cannot satisfy the conditions for self-sustaining discharge at the electrode gap (d). As a result, the discharge path varies along a longer path (s) to satisfy the conditions for self-sustained discharge, thereby maintaining the minimum breakdown voltage. This long-path discharge mechanism affects the ionization coefficient, resulting in an inconsistency between the ionization coefficient ratio at different distances and their respective scale factor (k) values. Therefore, on a micrometer scale, changes in the path make the application of similarity theory no longer applicable.