Publications

Results 1–25 of 41

Search results

Jump to search filters

1D PIC-DSMC analysis of a high-pressure nanosecond pulse discharge breakdown in helium

Journal of Physics D: Applied Physics

Echo, Zakari S.; Boerner, Jeremiah J.; Grillet, Anne M.

Kinetic simulations of plasma phenomena during and after formation of the conductive plasma channel of a nanosecond pulse discharge are analyzed and compared to existing experimental measurements. Particle-in-cell with direct simulation Monte Carlo collisions (PIC-DSMC) modeling is used to analyze a discharge in helium at 200 Torr and 300 K over a 1 cm gap. The analysis focuses on physics that would not be reproduced by fluid models commonly used at this high number density and collisionality, specifically non-local and stochastic phenomena. Similar analysis could be used to improve the predictive capability of lower fidelity or reduced order models. First, the modeling results compare favorably with experimental measurements of electron number density, temperature, and 1D electron energy distribution function at the same conditions. Second, it is shown that the ionization wave propagates in a stochastic, stepwise manner, dependent on rare, random ionization events ahead of the ionization wave when the ionization fraction in front of the ionization wave is very low, analagous to the stochastic branching of streamers in 3D. Third, analysis shows high-energy runaway electrons accelerated in the cathode layer produce electron densities in the negative glow region over an order of magnitude above those in the positive column. Future work to develop reduced order models of these two phenomena would improve the accuracy of fluid plasma models without the cost of PIC-DSMC simulations.

More Details
TYPE Journal Article YEAR 2020
DOIOSTIScopus

PIC-MCC Analysis of a High-Pressure Nanosecond Pulse Discharge Breakdown in Helium

IEEE International Conference on Plasma Science

Echo, Zakari S.; Boerner, Jeremiah J.; Grillet, Anne M.

Nanosecond pulsed discharges provide versatile experimental and computational testbeds for the exploration of fundamental plasma physics. In particular, the fast rise time and short duration produce plasmas which are both spatially diffuse and uniform enough to probe experimentally and confine the kinetics of interest to sufficiently short time scales to be computationally tractable. This work will focus on validation of particle-in-cell with Monte Carlo collisions (PIC-MCC) modeling and analysis of plasma phenomenon during and after formation of the conductive plasma channel of a nanosecond pulse discharge in helium at 200 Torr and 300 K over a 1 cm gap. The validation will compare results of the simulation to measurements of electron number density, temperature, 1D electron energy distribution function, and Townsend ionization coefficient, as well as ion mobility. Analysis of the stochastic nature of the electron avalanche ahead of the ionization wave front and of significant ionization overshoot in the presheath region is also performed.

More Details
TYPE Conference Poster YEAR 2018
OSTIScopus
Results 1–25 of 41
Results 1–25 of 41