Effect of collisions on the composition and optical properties of a nonequilibrium plasma behind the front of strong shock waves in Ar

Calculations are presented of the composition and optical properties of the plasma in the nonequilibrium region behind the front of strong shock waves in Ar with velocities of 10-25 km/s and pressures 300-760 torr. The collisions of a multicharged plasma are treated in the ring approximation of Debye theory in a macrocanonical ensemble. The composition of the two-temperature plasma is determined by solving the kinetic and energy-balance equations for the electrons. The length of the relaxation zone as a function of the speed of the shock wave is found. On the basis of the calculated nonequilibrium composition the spectral radiation fluxes are found from the solution of the transport equation. It is shown that as the velocity increases the effect on the optical properties of the plasma of the relaxation zone grows; the difference in the emission and equilibrium temperatures in the infrared and visible parts of the spectrum increases