Measurements of Temperatures and Densities in Shock-Heated Hydrogen and Helium Plasmas

Abstract

Temperatures and densities in plasmas produced by strong magnetically driven shock waves in a "$T$ tube" were measured spectroscopically. Local thermal equilibrium exists within the experimental accuracy for the conditions of this experiment. In both gases, the measured temperatures and densities are in disagreement with the values expected from the Rankine-Hugoniot relations, unless it is assumed that the conditions in the ambient gas are drastically affected by the initial discharge. Consistency between experiment and shock theory is achieved by considering magnetic pressure and dissociation and excitation of the ambient gas by uv radiation from the discharge.