Analyses of electron runaway in front of the negative streamer channel

L. P. Babich, E. I. Bochkov, I. M. Kutsyk, Torsten Neubert, Olivier Chanrion

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Abstract

X-and γ-ray emissions, observed in correlation with negative leaders of lightning and long sparks of high-voltage laboratory experiments, are conventionally connected with the bremsstrahlung of high-energy runaway electrons (REs). Here we extend a focusing mechanism, analyzed in our previous paper, which allows the electric field to reach magnitudes, required for a generation of significant RE fluxes and associated bremsstrahlung, when the ionization wave propagates in a narrow, ionized channel created by a previous streamer. Under such conditions we compute the production rate of REs per unit streamer length as a function of the streamer velocity and predict that, once a streamer is formed with the electric field capable of producing REs ahead of the streamer front, the ionization induced by the REs is capable of creating an ionized channel that allows for self-sustained propagation of the RE-emitting ionization wave independent of the initial electron concentration. Thus, the streamer coronas of the leaders are probable sources of REs producing the observed high-energy radiation. To prove these predictions, new simulations are planned, which would show explicitly that the pre-ionization in front of the channel via REs will lead to the ionization wave propagation self-consistent with REs generation.
Original languageEnglish
JournalJournal of Geophysical Research: Space Physics
Volume122
Issue number8
Pages (from-to)8974–8984
ISSN2169-9380
DOIs
Publication statusPublished - 2017

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©2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivsLicense, which permits use and distribution in any medium, provided the original work is properly cited, the use is
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