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Observed electric fields associated with lightning initiation
Author(s) -
Marshall T. C.,
Stolzenburg M.,
Maggio C. R.,
Coleman L. M.,
Krehbiel P. R.,
Hamlin T.,
Thomas R. J.,
Rison W.
Publication year - 2005
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 - 10.1029/2004gl021802
Subject(s) - lightning (connector) , electric field , thunderstorm , thermal runaway , physics , electron , volume (thermodynamics) , meteorology , nuclear physics , power (physics) , quantum mechanics , battery (electricity)
In situ electric field (E) measurements and inferred lightning initiation locations of three cloud‐to‐ground flashes are used to identify a thunderstorm region in which the preflash E exceeded the threshold for runaway breakdown. The maximum measured E in the region was 186 kV m −1 at 5.77 km altitude, which for runaway electrons is equivalent to 370 kV m −1 at sea level; this E value is ∼130% of the estimated threshold for an avalanche of runaway electrons. In addition, the volume where E exceeded the runaway threshold was estimated to be 1–4 km 3 , with a vertical depth of about 1000 m. At least within part of this volume the characteristic scale height for exponential growth of runaway electrons was 100 m or less. Thus for these three flashes the electric field conditions necessary for runaway breakdown existed, and runaway breakdown could have initiated the flashes.