On the Propagation of Streamers in Electrical Discharges

Abstract:

Streamers are non-thermal filamentary plasmas developing in insulating mediums under influence of strong external electric fields. Decades of extensive research have been dedicated to the understanding of streamer physics and their related applications. It is now well known that streamers are fundamental components in many types of gas discharges in laboratory and in the Earth’s atmosphere, such as the dielectric-barrier discharges, the lightning discharges in thunderstorms, and the sprite discharges in the upper atmosphere. Recent studies also suggest that streamers might play an essential role in the production of terrestrial gamma ray flashes in thunderstorms. In industry, streamers have a long history of being used for various applications such as ozone production, plasma-assisted combustion, and pollution control. Moreover, benefiting from their non-thermal property, streamers have recently shown a great medical potential, for example, in wound healing and treatment of skin diseases. Understanding of the streamer propagation mechanism is of essential importance for the studies of the above-mentioned electrical discharge phenomena, as well as the industrial and medical applications of streamers. According to the present knowledge on the streamer physics, the applied electric field plays a decisive role in controlling the streamer dynamics. In this study, we propose a new understanding of the streamer propagation mechanism, in which we refine some fundamental concepts in the streamer physics. We will discuss possible ways to flexibly control the streamer parameters in applications, and also implications of this new mechanism for understanding of fundamental sprite physics.