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Insights on Space‐Leader Characteristics and Evolution in Natural Negative Cloud‐to‐Ground Lightning
Author(s) -
Khounate Hamza,
Nag Amitabh,
Plaisir Mathieu N.,
Imam Abdullah Y.,
Biagi Christopher J.,
Rassoul Hamid K.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2021gl093614
Subject(s) - lightning (connector) , physics , line (geometry) , meteorology , cloud computing , space charge , geology , geodesy , computer science , geometry , mathematics , electron , power (physics) , quantum mechanics , operating system
We present sub‐microsecond‐scale, high‐speed video camera observations of three negative stepped leaders in cloud‐to‐ground flashes with return‐stroke peak currents (estimated by the U.S. National Lightning Detection Network) of −17, −104, and −228 kA. The camera frame exposure times for these observations were 1.8, 1.0, and 0.74 µs, respectively. The 0.74 µs exposure time is the shortest reported to date. We observed the temporal and spatial evolution of space leaders from their inception to their attachment to the pre‐existing leader channel (PELC). For stepped leaders that led to return strokes having higher peak currents, the space leaders appear to have incepted at farther median two‐dimensional distances from their respective PELC‐attachment points. These median distances were 6.1, 16.6, and 17.6 m, respectively, for the three strokes. Our observations indicate that space leader characteristics are likely influenced by stepped‐leader line‐charge‐density, which is expected to be higher in strokes with higher return‐stroke peak currents.