Experimental Study Of An Underexpanded Pulsed Plasma-Jet

1 2 An investigation has been conducted of the characteristics of a highly underexpanded pulsed plasma jet originating from an electrothermal capillary source. Measurements made include spatially and temporally-resolved emission spectroscopy, from which population temperatures and electron number densities were derived, and laser schlieren imaging of the precursor blast wave. The emission measurements were made at several locations along the jet axis, and at several times during the course of the discharge in order to investigate the development of the jet temperature and electron density fields. In general it is found that the temperature and electron density axial profiles - taken at different times during the discharge - are similar when the axial location is normalized by the distance from the jet exit to the Mach disk. For most of the discharge, the population temperatures upstream of the Mach disk are about 1.2 eV (14,000 K), but increase to 2.2 eV (25,000 K) just downstream of ..