Abstract : Intense and brief bursts of X-ray emissions have been measured during the stepping process
of both natural cloud-to-ground (CG) and rocket-triggered lightning flashes. In this paper, we investigate
theoretically the energy spectra of X-rays produced by the bremsstrahlung emission of thermal runaway
electrons accelerated in the inhomogeneous electric field produced around lightning leader tips. The X-ray
energy spectrum depends on the physical properties of the associated lightning leaders. Consequently,
X-ray measurements can be used for diagnostics of the electrical properties of lightning stepped leaders.
We report simulation results of the photon energy spectra produced by 5 and 10 MV negative CG lightning
discharges that would be measured from the ground using ideal detectors. We also quantify theoretically
the radial dependence of X-ray energy spectra received at ground level during the leader stepping process.
Moreover, it is found that the ground radiation generated in this process is harmless to humans.
https://hal-insu.archives-ouvertes.fr/insu-01174373
Contributor : Nathalie Pothier
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Submitted on : Thursday, July 9, 2015 - 9:35:53 AM
Last modification on : Thursday, July 25, 2019 - 4:16:02 PM
Long-term archiving on : Wednesday, April 26, 2017 - 1:30:06 AM
Wei Xu, Sebastien Celestin, Victor P. Pasko. Modeling of X-ray emissions produced by stepping lightning leaders. Geophysical Research Letters, American Geophysical Union, 2014, 41, pp.7406-7412. ⟨10.1002/2014GL061163⟩. ⟨insu-01174373⟩
