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 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 1013 to 1014 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.