Diagnostics and simulation of the initial ionization in NaCl-contaminated argon plasma

A method for cleaning shock tubes was investigated which involves glass bead peening of the shock-tube walls followed by multiple flushing of the tube. This method, however, left a practically irreducible and non-negligible residue of sodium chloride vapor in the tube. The observed time dependence of the electron density, the electron temperature, and the emitted sodium D light, in shock-heated argon contaminated by a small amount of sodium chloride vapor was simulated theoretically. It was found that accounting for the effects of contaminants requires important revisions in rate constants for pure argon from previously determined values.