The interaction of a plane shock wave ( M = 5) with an ionized plasma region formed before the arrival of a shock wave by a low-current glow gas discharge is considered experimentally and numerically. In the experiment, schlieren images of a moving shock-wave structure resulting from the interaction and consisting of two discontinuities, convex in the direction of motion of the initial wave, are obtained. The propagation of a shock wave over the region of energetic impact is simulated on the basis of the two-dimensional Riemann problem of decay of an arbitrary discontinuity with allowance for the influence of horizontal walls. The systems of Euler and Navier–Stokes equations are solved numerically. The non-equilibrium of the processes in the gas-discharge region was simulated by an effective adiabatic index γ. Based on the calculations performed for equilibrium air (γ = 1.4) and for an ionized nonequilibrium gas medium (γ = 1.2), it is shown that the experimentally observed discontinuities can be interpreted as elements of the solution of the two-dimensional problem of decay of a discontinuity: a shock wave followed by a contact discontinuity. It is shown that a variation in γ affects the shape of the fronts and velocities of the discontinuities obtained. Good agreement is obtained between the experimental and calculated images of density and velocities of the discontinuities at a residual gas temperature in the gas discharge region of 373 K.

For the conditions obtained in experiments on the interaction of a shock wave with an ionization unstable plasma, a numerical simulation of the impact of a thermally stratified energy source on the shock wave front is performed based on the full Navier-Stokes equations. It has been shown that its curvature, registered in schlieren-images, is associated with a higher temperature of the central layers of the source, and its disappearance is due to the multiple generation of the Richtmayer-Meshkov instabilities, which were obtained in the field of gas density. In addition, it was shown that when the source energy is redistributed into layers, local regions are formed behind the shock wave front with a gas temperature several times higher than the values for a homogeneous source.