Simple and inexpensive interferometry of shock wave developments from pulsed high-current discharge

Interferometer measurements are extremely informative in shock wave studies allowing direct evaluations of the gas density. The primary goal of the wo rk presented is to build a laser interferometer that meets the requirements of the highest possible simplicity, economy, convenience, and ease of cons truction. In our experiments, we used a low average power (10 mW) He-Ne las er without complication, expense, and environmental section. The He-Ne lase r interferometer with the Michelson arrangement was used to measure the lin e-averaged gas densities of shock waves. Temporal and spatial measurements of the density were performed for shock wave developments from high-current pulse discharges. The shock wave propagates in the radial direction of the discharge channel with supersonic speed. The shock velocity, however, decr eased from 2-0.5 km/s with the distance of the shock propagation. The width of the high density region, that is in the vicinity of the shock front was compressed from 3.5 to 1.8 mm according to the time variation of the disch arge current. (C) 2000 American Institute of Physics. [S0034-6748(00)00702- 4].