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Estimation of input energy in rocket‐triggered lightning
Author(s) -
Jayakumar Vinod,
Rakov Vladimir A.,
Miki Megumu,
Uman Martin A.,
Schnetzer George H.,
Rambo Keith J.
Publication year - 2006
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 - 10.1029/2005gl025141
Subject(s) - lightning (connector) , rocket (weapon) , electric field , radius , energy (signal processing) , physics , lightning strike , atmospheric electricity , meteorology , channel (broadcasting) , geodesy , environmental science , power (physics) , computational physics , geology , thunderstorm , electrical engineering , aerospace engineering , engineering , computer science , computer security , quantum mechanics
Electric fields in the immediate vicinity (within 0.1 to 1.6 m) of the triggered‐lightning channel were measured with Pockels sensors at the International Center for Lightning Research and Testing at Camp Blanding, Florida. These fields and the associated currents measured at the base of a 2‐m strike object were used to compute the input power and energy, each per unit channel length and as a function of time, associated with return strokes in rocket‐triggered lightning. In doing so, we assumed that the vertical component of the electric field at horizontal distances of 0.1 to 1.6 m from the lightning attachment point is not much different from the longitudinal electric field inside the channel (Borovsky, 1995). The estimated mean input energy over the first 50 μs or so is between 10 3 and 10 4 J/m, consistent with predictions of gas dynamic models, but one to two orders of magnitude smaller than Krider et al.'s (1968) estimate for a natural‐lightning first stroke, based on the conversion of measured optical energy to total energy using energy ratios observed in laboratory long‐spark experiments. The mean channel radius and resistance per unit channel length at the instance of peak power are estimated to be 0.32 cm and 7.5 Ω/m, respectively.