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Title: Evidence and Inferred Mechanism of Collisions of Downward Stepped‐Leader Branches in Negative Lightning
Abstract

Using visible‐range and infrared (3–5 µm) high‐speed video cameras, we observed collisions of adjacent branches in downward negative stepped leaders. Typically, a lagging (chasing) branch (CB) approached a leading branch (LB) from aside at about 90° angle and connected to the lateral surface of the LB within some tens of meters or less of its tip. We infer that collisions can be facilitated by the attracting force of upward moving positive‐charge wave associated with stepping at the leading branch tip. Outcomes of branch collisions differ. The chasing branch may be absorbed by the LB, rebound, or temporarily bridge two branches. It appears that a heavily branched negative stepped leader creates a highly structured and rapidly changing electric field pattern inside the volume it occupies. We observed abrupt changes in the direction of branch extension, suggesting that the direction of local electric field can differ significantly from the ambient.

 
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Award ID(s):
1701484
NSF-PAR ID:
10446494
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Geophysical Research Letters
Volume:
48
Issue:
11
ISSN:
0094-8276
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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