We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
High‐Speed Video Observations of Needles Evolving Into Negative Leaders in a Positive Cloud‐To‐Ground Lightning Flash.
- Authors
Wu, Bin; Qi, Qi; Lyu, Weitao; Ma, Ying; Chen, Lyuwen; Lyu, Fanchao; Zhang, Yang; Fan, Yanfeng; Rakov, Vladimir A.
- Abstract
High‐speed video records of a single‐stroke positive cloud‐to‐ground (+CG) flash were used to examine the evolution of eight needles developing more or less radially from the +CG channel. All these eight needles occurred during the later return‐stroke stage and the following continuing current stage. Six needles, after their initial extension from the lateral surface of the parent channel core, elongated via bidirectional recoil events, which are responsible for flickering, and two of them evolved into negative stepped leaders. For the latter two, the mean extension speed decreased from 5.3 × 106 to 3.4 × 105 and then to 1.3 × 105 m/s during the initial, recoil‐event, and stepping stages, respectively. The initial needle extension ranged from 70 to 320 m (N = 8), extension via recoil events from 50 to 210 m (N = 6), and extension via stepping from 810 to 1,870 m (N = 2). Compared with needles developing from leader channels, the different behavior of needle flickering, the longer length, the faster extension speed, and the higher flickering rate observed in this work may be attributed to a considerably higher current (rate of charge supply) during the return‐stroke and early continuing‐current stages of +CG flashes. Plain Language Summary: This paper presents the dynamics of eight needles appearing on the lateral surface of the channel of a single‐stroke positive cloud‐to‐ground lightning flash. Six needles, after their initial extension, elongated via recoil events, which are responsible for flickering, and two of them evolved into negative stepped leaders. This study helps to improve our understanding of the dynamics of needles and explain the mechanism of recently discovered initiation of negative leaders from positively charged channels. Key Points: Dynamics of two needles developing from a +CG channel and evolving into negative stepped leaders were studied in detailAfter initial extension from +CG channel, needle channels first elongated via bidirectional recoil events and then via steppingExtension speeds were 5.3 × 106, 3.4 × 105, and 1.3 × 105 m/s during the initial, recoil‐event, and stepping stages, respectively
- Subjects
NEEDLES &; pins; LIGHTNING; VIDEO recording; THUNDERSTORMS
- Publication
Journal of Geophysical Research. Atmospheres, 2023, Vol 128, Issue 21, p1
- ISSN
2169-897X
- Publication type
Article
- DOI
10.1029/2023JD039523