Corner-Expansion Flow of Ionized Argon

Abstract

The recombination rate constant for ionized argon as a function of temperature was determined by using dual-frequency laser interferometry to measure total density and electron number density in a 15° corner-expansion flow. The flow was induced by a normal shock wave in a 4 in. × 7 in. (10.2 cm × 17.8 cm) hypervelocity shock tube over a range of initial shock Mach numbers [Formula: see text] and pressures [Formula: see text] Torr at room temperature T1 ~ 300 °K, with impurity levels less than 150 parts per million.