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Return stroke speed of cloud‐to‐ground lightning estimated from elve hole radii
Author(s) -
Blaes P. R.,
Marshall R. A.,
Inan U. S.
Publication year - 2014
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 - 10.1002/2014gl062392
Subject(s) - lightning (connector) , radius , stroke (engine) , meteorology , physics , computer science , power (physics) , computer security , quantum mechanics , thermodynamics
We present the first measurements of the lightning return stroke speed that directly relate to the current return stroke, as opposed to its optical manifestation. The shape of elves is determined by the electromagnetic pulse (EMP) radiation pattern at D region altitudes, which is in turn controlled by the geometry and current propagation properties of the return stroke channel. In particular, numerical simulation of the EMP‐ionosphere interaction shows a strong relationship between the elve “hole” radius and the current return stroke speed. The hole radii are measured from a data set of 55 elves observed with the PIPER photometer. Using these radii observations in conjunction with numerical simulations of the EMP, we perform Bayesian inference to estimate the distribution of return stroke speeds. The results show a maximum a posteriori probability return stroke speed estimate of 0.64 c for elve producing lightning.