CURRENT SHEET DYNAMICS IN AN INVERSE PINCH SHOOCK TUBE

Experiments were performed in argon, helium, and hydrogen in an inverse pinch electromagnetic shock tube. The current sheet and shock wave trajectories were measured by using magnetic pickup coils and piezoelectric pressure probes, respectively, and the electron number density was determined from electrostatic probes and by using the Stark broadening effect on spectral lines. The experimental parameters vary from conditions where the dominant heating mechanism in Ohmic dissipation to those where shock heating is greater. Snowplow speed for the current sheet is measured in all cases and low levels of ionization within the sheet were observed for the conditions where Ohmic dissipation was the only heating mechanism. A description of how a current sheet with a low degree of ionization can sweep up the gas it encounters (snowplow) is given.