Influence of the external electrical circuit on the regimes of a nanosecond repetitively pulsed discharge in air at atmospheric pressure

This paper presents 2D simulations of nanosecond repetitively pulsed discharges in air at atmospheric pressure coupled with a model of the external electrical circuit used in experiments. Then, during the pulsed discharge, the voltage applied to the electrodes varies in time as a function of the time dependent value of the plasma channel conductivity. In this work, we have simulated several consecutive nanosecond pulsed discharges between two point electrodes in air initially at 1000 K at a frequency of 10 kHz. First, we have simulated three consecutive nanosecond spark discharges. We have shown that the air temperature increases significantly pulse after pulse in the discharge channel. As a consequence, for the three consecutive simulated nanosecond spark discharges, we have put forward a decrease in the discharge radius, pulse after pulse. Then, to further limit the discharge current, a ballast resistance R has been added into the electrical circuit and the results are presented for seven consecutive nanosecond discharges. For a value of R = 1000 Omega in the conditions studied in this work, we have shown that the first nanosecond discharges are in the glow regime, with a small gas heating per pulse. However, as the number of pulses increases due to the gas heating by each pulse, the discharge may transit to a multipulse nanosecond spark regime. For a higher value of R = 10 000 Omega, we have put forward that the gas heating by each nanosecond discharge becomes negligible and then the multipulse nanosecond discharge remains in this case in a stable 'quasi-periodic' multipulse glow regime.