Influences of Shock Waves on High-Pressure, Pulsed Glow Discharge due to Excimer Laser Excitation

Abstract

The high-pressure, pulsed glow discharge has been studied to gain a further understanding of the excitation discharge on application of excimer lasers. The influence of shock waves on the discharge has been investigated disregarding other factors which may affect the discharge instabilities, such as gas density depletion, discharge products, residual ions, halogen gas, and electrode heating. A shock wave of 1.2 in Mach number is produced by a shock tube with a gas mixture of helium and argon. It is found that if the shock wave, propagating across the discharge direction, does not reach the middle of the discharge region, glow discharge occurs only in front of the shock wave. Even if the shock wave passes through the middle of the discharge region, the glow discharge occurs only in front of the shock wave. However, an arc-like filament through the shock front is also produced. If the shock wave passes through the discharge region, the glow discharge can be produced again behind the shock front, however, a surface discharge is also produced between the main electrode and the pre-ionization pin electrode.