Nanosecond Repetitively Pulsed Discharge

Nanosecond Repetitively Pulsed (NRP) discharges are associated with the generation of non-equilibrium plasmas in atmospheric conditions and efficient production of reactive and ionized species. These plasmas are of interest in combustion and aerodynamic flow control applications. In the combustion field, NRP plasmas have been used to increase flame speed, enhance flame stabilization at low fuel/oxidizer ratios, and mitigate combustion instability. For aerodynamic flow control, NRP discharges were utilized for controlling boundary layer for subsonic lows, shock wave modification for supersonic flows, and inducing flow instabilities by generating pressure waves.

We are studying the physics of NRP discharges in a pin-to-pin configuration in corona and spark discharge regimes. This involves studying the dynamics of the plasma and gas parameters on very different timescales varying from the single nanoseconds required to resolve the dynamics during the ns-pulse to the millisecond-times typical for the decay stage between the ns-pulses. Additional thrust is on the development of diagnostic tools that can be used for NRP discharges. We have developed a method of microwave scattering on NRP plasmas for measurements of the total number of electrons generated in the discharge and electron number density. We have also created a method for temperature measurements with 5 ns temporal resolution that can be used for a great variety of applications beyond the NRP discharges requiring time-resolved gas thermometry.

NRP experiment and diagnostics

References:

1. X. Wang, P. Stockett, R. Jagannath, S. Bane, and A. Shashurin “Time-Resolved Measurements of Electron Density in Nanosecond Pulsed Plasmas Using Microwave Scattering” Plasma Sources Sci. Technol. 27, 07LT02 (2018).
2. X. Wang, and A. Shashurin “Gas thermometry by optical emission spectroscopy enhanced with probing nanosecond plasma pulse” AIAA Journal, accepted (2020).