High‐Speed Video Observation of Needles Formed During the Leader Stage in a Positive Cloud‐to‐Ground Flash

Le résumé fourni par la source

Abstract High‐speed video and electric field records of a positive cloud‐to‐ground (+CG) flash were used to examine six needles that were formed during the leader stage (a previously undocumented phenomenon in +CGs), each including the initial extension followed by flickering events, and subsequently re‐illuminated after the return‐stroke (RS) onset. During the leader stage, both the initial extension and following flickering events of these six needles always initiated from the lateral surface of the positive leader branch channel core. In contrast, after the RS onset, these six needles initially extended from the channel core, while the following flickering events initiated at a distance from the core and were bidirectional processes. We interpreted the disparity as being due to differences in the corona‐sheath structure before and after the RS onset.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.