Observations of Fine‐Scale Structures During the Pause Period of Positive Leader Discharge

Abstract In positive leader discharge, the channel evolution process during pause period significantly impacts the subsequent discharge behavior accompanied by sudden elongation and intense reillumination of the discharge channel. The discontinuous discharge phenomenon is widely observed in the intermittent positive leader of natural lightning and laboratory positive long air gap discharge. In this study, direct optical photography and schlieren observation system were designed to acquire the time‐resolved morphology images of optical and thermal plasma channel during pause period of positive leader discharge. The synchronized propagation of luminous and thermal channels within pause duration is experimentally characterized. Besides, it is confirmed that the secondary streamer triggering leader inception bursts in front of the residual channel within pause duration and further reactivates the discharge channel, providing insight into the stepped propagation mode of positive leader discharges in nature lightning and restrike phenomenon.