A Dynamic Model of Streamer Coupling for High Pressure Discharges

TL;DR

This paper develops a dynamic streamer coupling model for high pressure discharges, explaining formation of homogeneous emission and high-speed patterns by considering electron diffusion and drift effects, with results matching experiments.

Contribution

It introduces a new streamer coupling theory that accounts for electron diffusion and drift, predicting conditions for homogeneous emission and high-speed patterns in high pressure discharges.

Findings

Minimum preionization level $n_{min} \,\sim\, 10^5$ cm$^{-3}$ for streamer coupling.

Predicted emission pattern speeds range from 10^4 to 10^6 m/s.

Model predictions agree with experimental observations.

Abstract

A streamer coupling theory is developed to describe the formation of homogenous emission, and the high moving speed of emission patterns in high pressure discharges. By considering the effects of both electron diffusion and electronic drift in the streamer head, the minimum required preionization level $n_{\rm min}$ for the formation of streamer coupling is found to depend on electric field strength, gas pressure and electron temperature. The homogeneity and moving speed of the emission pattern in streamer coupling head increase with preionization level $n_0$, when $n_0 > n_{\rm min}$. The predicted results for atmospheric helium plasma indicate $n_{\rm min} \sim 10^5~{\rm cm^{-3}}$ and moving speed of $10^4 - 10^6$ m/s, in agreement with experiments.