The spectroscopic and probe methods are used to measure the microscopic parameters of plasma of pulsed and stationary transverse discharges in a supersonic air jet flowing into a submerged space. The measurements are performed for the Mach number of flow M = 2, submerged space pressure p = 5 to 30 kPa, degree of the jet being off-design n ≈ 2, and discharge current I = 1 to 10 A. The discharge current dependences of the average values of gas temperature, charged particle concentration, and reduced electric field are measured for a discharge mode close to that of current generator. The measured values of gas temperature lie in the range of 1 to 3 kK, those of charged particles concentration -of 10 13 to 10 14 cm -3 , and of reduced electric field -of 40 to 20 Td. The axial distribution of temperature is characterized by high values of temperature even at short distances from the electrodes and by a slow decrease along the flow.

A model of heat source is validated for the description of the gasdynamic aspects of interaction between a discharge channel and supersonic flow, which are defined by the heating of gas. The model is based on the characteristic features of a discharge in supersonic flow, which are observed in the case of nonequilibrium plasma whose conductivity is defined by the degree of ionization, namely, rapid heating of air in the electrode regions and relatively low values of reduced electric field in extended discharge channels behind these regions. The rapid heating mechanism leads to a redistribution of the power of Joule heat to the front part of the channel, which enables one to simulate a discharge as a heat source with a short ellipsoidal zone of heat input. This approach enables one to attain agreement between the calculated axial distributions of temperature and velocity of flow and the experimental data. It is demonstrated that unsteady-state conditions of energy input make it possible to experimentally simulate gasdynamic effects of interaction between stationary heat sources and supersonic flow when single pulses are used and in the case of pulse-periodic mode.

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In this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been corrected.