Insulator Ablation in Magnetic Piston Shock Tubes

The effect of end wall insulator ablation on the performance of magnetic piston shock tubes has been investigated theoretically. From the analysis of a steady flow model, a simple correlation parameter has been derived that permits a quick determination of the loss in a given experiment. The parameter is a function only of the magnetic drive field, initial test gas density, and the ionization energy of the insulator vapor. The transient heating of the insulator that initiates the vaporization is discussed as is the effect of degassing adsorbed material at the wall surface.