A Dynamic Model of Streamer Coupling for High Pressure Discharges

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.