A quantitative laser schlieren method for measurement of neutral gas density in high-pressure gas switches

Abstract
A quantitative laser schlieren technique has been developed to measure the changes in neutral gas density inside a spark gap switch after breakdown. The measurement system incorporates an array of narrow laser beams which are used to probe the inter-electrode gas volume at discrete distances from the spark axis. Changes in the refractive index gradient within the switch, caused by variations in neutral gas density, result in beam deflection, which is measured using a neutral density wedge/photodiode combination. The resulting schlieren profiles yield both spatially and temporally resolved refractive index data, which enable calculation of the gas density. The use of four averaged trials to obtain the final neutral gas density profiles minimizes errors caused by the turbulent nature of the cooling gas. A typical set of results is presented for SF6 at a pressure of 0.5 bar.

This publication has 10 references indexed in Scilit: