On possible structures of normal ionizing shock waves in electromagnetic shock tubes

Abstract

The problem of possible structures of normal ionizing shock waves is studied. On the basis of the general theory of ionizing shock waves in magnetic fields previously developed Liberman and Velikovich, 1981, a similarity solution of the piston problem for an impenetrable piston and a magnetic piston is described and a numerical solution of the non-stationary piston problem is obtained. It is shown that precursor photo-ionization of the neutral gas by the radiation of the shock-heated gas is the dominant factor in shaping normal ionizing shock structures. In particular, it is shown that the strong overheating of atoms and ions in shock fronts is due to the tensor form of Ohm's law in the precursor region. The conditions of formation of type 3 and type 4 shock structures are elucidated together with the limits of applicability of the Chapman-Jouguet hypothesis. The theory is applied to the interpretation of the experimental data on normal ionizing shock waves.