Gas density dynamics in pulsed interelectrode discharge trace

We present a numerical investigation into the dynamic processes governing the formation of a rarefied region in air at pressures of 10.7 and 101.3 kPa, maintained at temperature of 300 K, influenced by plasma heating from an interelectrode microsecond discharge. Experimental validation of our computational findings was conducted specifically for a pressure of 101.3 kPa. Our estimations reveal a remarkable agreement between the experimentally measured nested energy value of 57 $\pm$ 6 mJ and our numerical prediction, which stands at approximately 58 mJ. We observed a significant spatiotemporal congruence in the medium density distribution. Within the interelectrode gap, the gas density diminishes to 0.1 times its initial value within a time frame of 3 $\mu$s, predominantly due to the formation of radially expanding flow zones. Notably, gas density experiences a more rapid decline near the electrodes, attributed to the higher local specific heating power and the consequent emergence of near-electrode shock waves.