Dynamic model of streamer coupling for the homogeneity of glowlike dielectric barrier discharges at near-atmospheric pressure.

A streamer coupling theory is developed to describe the formation of homogenous emission and the high propagation speed of emission patterns in near-atmospheric pressure discharges. By considering the effects of both electron diffusion and electronic drift in the streamer head, the minimum required preionization level n(min) for the formation of streamer coupling is found to be dependent on electric field strength, gas pressure, and electron temperature. The final stage of discharge is a microdischarge, when the preionization level n(0) is smaller than n(min). However, when n(0) is larger than n(min), streamers can couple to each other and form a glowlike discharge, and the homogeneity and propagation speed of the emission pattern in the streamer coupling head increases with the preionization level. The streamer coupling model can also be possibly used to explain many phenomenon in near-atmospheric pressure discharges, such as the bulletlike luminous discharge when atmospheric pressure plasma jets eject into ambient air.