Speaker
Description
The dynamics of streamers in PIC-DSMC simulations of 3D pin-to-plane wedge geometries are formally quantified for several azimuthally swept wedges in terms of electron velocity and density as temporal functions of spatial direction and coordinates r,$\phi$,z. Particles are tracked with picosecond temporal resolution out to 1.4 nanoseconds, spatially binned, and averaged over six independent simulations each sourced with a random plasma seed. An air model$^1$ comprised of Townsend breakdown and streamer mechanisms via tracking excited state neutrals that can either undergo quenching or spontaneous photon emission collisions$^2$ is employed. A 100 $\mu$m radius 1 eV plasma with a 10$^1$$^8$ m$^-$$^3$ particle density placed at the tip of a 100 $\mu$m hemispherical pin electrode (at 6 kV) in a 600 Torr air filled gap, 1.5 mm above a planar grounded cathode, seeds the domain. Prior 2D studies have shown that the reduced electric field, E/n, can significantly impact streamer evolution$^3$. We extend the analysis to 3D wedge geometries (to limit computational costs) with wedge angle azimuthally swept in 15$^o$ increments from 15$^o$ to 45$^o$ to examine the wedge angle’s effect on streamer branching, propagation, and velocity. Initial results suggest that solution convergence in terms of the parameters described above may be achievable.
- C. Moore et al., Development of PIC-DSMC Air Breakdown Model in the Presence of a Dielectric, ICOPS, 2016.
- A. Fierro et al., Discrete Photon Implementation for Plasma Simulations, Physics of Plasma, 23, 2016.
- A. Jindal et al., Streamer Formation Near a Dielectric Surface with Variable Quantum Efficiency, ICOPS, 2017.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
