Optical emissions associated with terrestrial gamma ray flashes

Abstract : Terrestrial gamma ray flashes (TGFs) are high-energy photon bursts produced by high-energy electrons originating in the Earth’s atmosphere through bremsstrahlung processes. In this paper, we present modeling studies on optical emissions resulting from the excitation of air molecules produced by the large population of electrons involved in TGF events based on two possible production mechanisms: relativistic runaway electron avalanches (RREAs) and acceleration of thermal runaway electrons produced by high-potential intracloud lightning leaders. Numerical models developed in this study are first validated through the calculation of fluorescence emissions from air excited by energetic electrons and comparison with available laboratory observations. Detailed discussion of the role of excitation and ionization collisions on the formation of the electron energy distribution is presented. Moreover, using Monte Carlo simulations, we show that electron energy distributions established from the two TGF production mechanisms considered here are inherently different over the full energy range. The strong energy dependence of the capability of electrons to generate excited states responsible for optical emissions from neutral and ionized nitrogen molecules leads to intrinsic differences in optical emissions produced by different mechanisms of TGF production. We also show that TGFs are most likely accompanied by detectable levels of optical emissions and that the distinct optical features are of significant interest for constraining and validating current TGF production models.
Document type :
Journal articles
Complete list of metadatas

Cited literature [55 references]  Display  Hide  Download

https://hal-insu.archives-ouvertes.fr/insu-01182137
Contributor : Nathalie Pothier <>
Submitted on : Thursday, July 30, 2015 - 3:03:19 PM
Last modification on : Wednesday, September 4, 2019 - 2:22:04 PM
Long-term archiving on : Saturday, October 31, 2015 - 10:40:47 AM

File

Xu_et_al-2015-Journal_of_Geoph...
Publisher files allowed on an open archive

Identifiers

Collections

Citation

Wei Xu, Sebastien Celestin, Victor P. Pasko. Optical emissions associated with terrestrial gamma ray flashes. Journal of Geophysical Research Space Physics, American Geophysical Union/Wiley, 2015, 120, pp.1355-1370. ⟨10.1002/2014JA020425⟩. ⟨insu-01182137⟩

Share

Metrics

Record views

156

Files downloads

161