Transient glow discharges in laser excitation and breakdown

Abstract

The spatiotempora1 development of discharges in parallel plane gaps at high overvo1tage has been studied for many years in order to understand the physical mechanisms of breakdown. These studies have shown that a glow discharge structure is produced, even at high overvoltages where the duration of the glow discharge can be as short as tens or hundreds of nanoseconds. Recently, these transient glow discharges have been used as a pumping source for a variety of gas lasers including CO 2 lasers and rare gas-halide excimer lasers. Ultraviolet preionization of the gas volume is widely used to “stabilize” these laser glow discharges, i.e., to increase the energy which can be deposited into the discharge without causing a glow-to-arc transition. There has also been recent work which indicates that the corona discharges which occur in point-plane gaps have a glow discharge structure. The phenomena that are observed in these three types of discharges will be compared. We will also offer some speculations about the “corona stabilization” process that is observed in the breakdown of point-plane gaps in SF 6 and SF 6 mixtures.