IONIZING SHOCK STUDIES IN AN ELECTROMAGNETICALLY DRIVEN SHOCK TUBE
COLUMBIA UNIV NEW YORK PLASMA RESEARCH LAB
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A coaxial electromagnetic shock tube was used to study ionizing shocks propagating through hydrogen. An experiment is described which produced plane switch-on ionizing shocks. Studies were conducted covering the sub- Alfvenic, trans-Alfvenic and super-Alfvenic regimes. Data is presented that verifies the existence of switch-on fronts in all these regimes, and demonstrates the significant effect of the initial electric field on the shock jump conditions. The results substantiate the theory of normal ionizing shocks developed by Taussig. A simple physical criterion is employed to choose from among the several theoretically predicted ionizing waves propagating at a given speed. This criterion has strong intuitive support and results in a consistent picture of ionizing shock propagation that is in general agreement with out experimental observations. The existence of a small homogeneous plasma sample, behind the ionizing shock wave and before the expansion fan, is demonstrated. Previous failures to find large homogeneous plasma samples are shown to be consistent with the theory of ionizing shock waves.
- Plasma Physics and Magnetohydrodynamics