The effect of fore-shock heating in the plasma drag-reduction problem

A¹ 2-D numerical investigation is presented of shock wave propagation into a gas, whose density is modulated in the transverse direction across the width of a shocktube. These density modulations represent temperature distributions, in which low density corresponds to high temperature gas and high density corresponds to low temperature gas. This work is motivated by recent shock-plasma experiments, and mechanisms to explain the experimentally observed shock "splitting" signatures are investigated. It is found that the shock "splitting" signatures are reproduced when the shockwave is strongly curved or bowed. This occurs as the depth of the initial density profile is increased. The gross features of the shock "splitting" signatures are relatively insensitive to variations in the shape of the initial density profile (into which the shock propagates).