Normal Ionizing Shock Waves

Solutions to the steady-state jump equations are obtained for a normal ionizing shock wave propagating into a nonconducting, quiescent gas in an electromagnetic field. Comparison of these solutions to pure magnetohydrodynamic shocks and ordinary gas shocks indicates that ionizing shocks are hybrids having some properties common to both magnetohydrodynamic and gas shocks. Some completely novel effects are produced by the upstream electromagnetic field. The shock velocities are bounded for a given upstream electric field strength where the electric field is assumed parallel to the shock plane. For electric fields larger than a critical value, Ec, no steady compressive shocks exist, and for nonzero electric fields ``switch-on'' behavior is extended to slow shocks. Solutions analogous to detonation-deflagration waves have been found, and the Chapman-Jouguet condition is applied to them. The complete boundary value problem is solved in the context of an electromagnetic annular shock tube to place the analytic results in the framework of experimentally observable phenomena.