Transverse electric discharges in supersonic air flows: microscopic characteristics of discharge

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 $\mathrm{M}=2$, submerged space pressure $p=5$ to $30$ kPa, degree of the jet being off-design $n\approx2$, 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 $10^{13}-{10}^{14}$ 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.