Observations of the Breakthrough Phase of Attachment Process in Laboratory Long Sparks

Abstract

High‐speed video frames and discharge current records of 34 long laboratory sparks were examined. Two consecutive frames of the breakthrough phase, depicting the evolution of the common streamer zone, were obtained in five events, all presented in this study. Two types of luminous structures were observed inside the common streamer zone just before the return stroke phase: the floating luminous segment and the luminous channel linking the opposite polarity leaders. The luminous structure served as a selected route for the return stroke channel. These results demonstrate that the transformation of high‐impedance common streamer zone into a hot plasma channel may involve two main features: the common streamer zone shrinking and the dominant development of the selected route.

Unusual Plasma Formations Produced by Positive Streamers Entering the Cloud of Negatively Charged Water Droplets

“…There is a growing body of evidence that positive leaders in long sparks and lightning can also involve space leaders formed inside or near the streamer zone extending from the leader tip (see Huang, Chen, Fu, Fu, et al., 2022; Huang, Chen, Fu, Xiang, et al., 2022; Huang et al., 2021; Kostinskiy et al., 2018). Space leaders were also observed inside the common streamer zone of the breakthrough phase of the lightning (Biagi et al., 2009; Gamerota et al., 2015) and long spark (Fu et al., 2022) attachment process.…”