Dynamics of radiation from nanosecond surface sliding discharge in airflow with shock waves

Spatio-temporal distributions of radiation from pulsed sliding surface discharge of $\sim$300-ns duration in quiescent air at pressures within 2–200 Torr and in the presence of shock waves in supersonic flow with Mach numbers M = 2.8–3.3 have been experimentally studied. The dynamics of radiation from discharge was analyzed based on processing of the streak images and nine-frame images of discharge glow intensity, emission spectra, and discharge current kinetics. It is established that variation of the radiation intensity from discharge interacting with shock waves is correlated with a model temporal dependence of the population of $C^3\Pi_u$ states of nitrogen during shock compression of the discharge plasma region.