Experimental study of the hydrodynamic expansion following a nanosecond repetitively pulsed discharge in air

Abstract

We report on an experimental study of the hydrodynamic expansion following a nanosecond repetitively pulsed (NRP) discharge in atmospheric pressure air preheated up to 1000 K. Single-shot schlieren images starting from 50 ns after the discharge were recorded to show the shock-wave propagation and the expansion of the heated gas channel. The temporal evolution of the gas temperature behind the shock-front is estimated from the measuredshock-wavevelocity by using the Rankine-Hugoniot relationships. The results show that a gas temperature increase of up to 1100 K can be observed 50 ns after the nanosecond pulse.