Nonequilibrium Factor in the Structure of a Curved Shock Wave Refracted Into an Intensively Heated Medium

The role of thermal nonequilibrium state in the structure of a curved shock wave during its refraction into an intensively heated medium has been studied analytically and numerically. At elevated gas temperatures common for optical discharges and for moderate-to-strong shock intensities, the width of the zone of variable specific heat is on sub- to mm scale, and thus is comparable to the geometrical scale of the problem. The asymptotic temperature gap, the specific temperature distribution in the zone, and the relaxation zone width are discussed in connection with the changes in the contrast level of the shock images obtained with shadow techniques. Numerical examples are presented in spherical and elliptical geometries for the conditions of a laser-induced breakdown in pure nondissociating nitrogen gas.