Diane L. Rusterholtz

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

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 measured shock-wave velocity 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.

Images of a Nanosecond Repetitively Pulsed Glow Discharge Between Two Point Electrodes in Air at 300 K and at Atmospheric Pressure

For many applications of atmospheric pressure plasmas, a crucial issue is to obtain glow discharges at 300 K. We have generated such plasmas with a nanosecond repetitively pulsed method. We present experimental and simulated optical emission images of the dynamics of the formation of the glow regime at the early stages of its development.

Investigation of the Hydrodynamic Expansion Following a Nanosecond Repetitively Pulsed Discharge in Air

We report on an experimental study of the hydrodynamic expansion following a Nanosecond Repetitively Pulsed (NRP) discharge in atmospheric pressure air at 300 and 1000 K. The discharge is created by voltage pulses of amplitude 10 kV, duration 10 ns, applied at a frequency of 1-10 kHz between two pin electrodes. The electrical energy of each pulse is of the order of 1 mJ. We recorded single-shot schlieren images starting from 50 nanosecond after the discharge. The time-resolved images 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 measured shock-wave velocity by using the Rankine-Hugoniot relations. The results show that the gas heats up by almost 1100 K within 50 ns after the pulse. This fast gas heating is consistent with a two-step mechanism involving electron-impact excitation of N 2 followed by the dissociative quenching of the excited electronic states of N 2 by O 2 .