Precursor ionization effects on magnetohydrodynamic switch-on shock structure

The influence of shock-induced precursor ionization on the steady-state structure of switch-on shock waves with non-equilibrium ionization and radiation is examined theoretically. A single-temperature monatomic gas is assumed, together with a Clarke-Ferrari model for photoionization of the upstream gas. It is found that the effect of the precursor depends in general on the ratio of a characteristic precursor length to a characteristic magnetic interaction length. For the slightly ionized case treated in some detail, this ratio is much greater than unity, indicating a precursor-independence for the magnetohydrodynamic shock structure.