Study of transient processes in nitrogen by measurements of dynamic breakdown voltages

Abstract

In this paper the measurements of the dynamic breakdown voltages U b for linearly rising pulses in nitrogen at low pressure are presented. The measurements were carried out for the rates of voltage rise k up to $300\, {\rm V\,s}^{-1}$ . Dependence of the breakdown voltages, delay times and electron yields on the rate of rise were obtained experimentally and theoretically under different conditions. It was found that the overvoltage $\overline {\Delta U_b}$ and the mean effective electron yield $\overline {YP}$ is proportional to $\sqrt k$ ( Y is a number of generated electrons in the interelectrode space per second and P the breakdown probability), while the statistical time delay $\overline t_s$ is proportional to $1/\sqrt k$ . In the second part, the experimental breakdown voltage distributions were obtained, fitted by theoretical distributions and some breakdown parameters relevant to experimental conditions were determined. Based on the approximate analytical and numerical models, the dependence of the effective secondary electron yield γ on the overvoltage and on the rate of voltage rise were derived from these measurements. It was found that γ varies linearly with the overvoltage for a constant k , and the slope of γ is proportional to $\sqrt k$ .