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The results of numerical modeling of laser energy supply in a supersonic flow are presented. In contrast to the common approach, in the new calculation model, not only the absorbed power is taken into account, but also the plasma breakdown impulse in the domain of emission focusing does. The value of the impulse is determined using the model of radiation absorption behind the front of the laser-supported detonation wave. An analysis of the results is presented.

The ionization rate of argon in a relaxation zone behind the shock wave front was measured in stable flow regimes with Mach numbers above 11. Based on an analysis of the electron energy balance equation, it is suggested that high (as compared to the results of calculations) values of the avalanche ionization rate are related to the existence of an additional channel of the energy transfer during the associative ionization of argon atoms.

The state of argon plasma behind the shock wave front was experimentally studied in the flow regimes with Mach numbers M = 11−12. Using the results of simultaneous measurements of the optical emission and absorption at a wavelength of 10.6 μm, the electron temperatures in the relaxation zone and in the equilibrium region are evaluated.

A comparative analysis of the gas flow regimes behind the region of laser energy supply to a supersonic jet is performed depending on the laser radiation focusing conditions. A relationship established between the energy and gasdynamic parameters reveals a significant difference in the flow parameters (velocity, stagnation pressure) behind the extended and localized (point) thermal plasma sources for the identical initial conditions in a supersonic jet with the Mach numbers M=1.5–10.

An analytical method for determining the wave structure and quasistationary flow parameters of an optical pulsating discharge plasma expanding in a supersonic flow is developed. The method is based on a physical model of the optical gas breakdown, a theory of the point explosion, the results of numerical modeling of the breakdown plasma dynamics along a laser beam, experimental data, and numerical estimates.

The ionization rates of argon and krypton were measured in a relaxation zone behind the shockwave front for the Mach numbers corresponding to stable flow regimes close to the threshold for development of the flow instability of types I and II. The experimental rates of the avalanche ionization exceed theoretical predictions. It is suggested that the discrepancy is related to the existence of an additional channel for the energy transfer between particles.

An analysis is made of experimental data on the influence of a pulse-periodic optical discharge in a supersonic argon stream on the aerodynamic drag of streamlined objects. The interrelation established between the parameters of the laser radiation and the stream is used to determine the threshold frequency of the laser pulses which determines the transition to quasi-steady-state flow.