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Communication Dans Un Congrès Année : 2019

Statistical estimation of the electric field amplitude in TGF source regions through the deviation of relativistic electron beams by the geomagnetic field

Résumé

Terrestrial gamma-ray flashes (TGFs) are bursts of high-energy photons originating from the Earth's atmosphere in association with thunderstorm activity [e.g., Briggs et al., JGR, 118, 3805, 2013]. TGFs are believed to be typically produced at altitudes ranging from 10 to 14 km [e.g., Cummer et al., GRL, 41, 8586, 2014]. Relativistic runaway electron avalanches (RREAs) are understood to be the root cause of TGFs but the exact context and configuration of electric fields driving RREAs is currently under debate [e.g., Dwyer et al., Space Sci. Rev., 173, 133, 2012].

In this work, we study the effects of the geomagnetic field combined with the driving electric field on the runaway electron beam geometry. Electron beams naturally follow the direction of the electric field, but the geomagnetic field should cause them to bend. Since the geomagnetic field close to the Earth's surface is known precisely, quantifying the statistical deviation of TGFs in satellite observations gives information on the electric field at the source. We present an analytical method to calculate the relativistic electron beam deviation in arbitrary homogeneous electric and magnetic fields. Moreover, we show that a statistically significant West-East asymmetry consistent with the deviation of RREAs by the geomagnetic field is present in the Fermi-GBM TGF catalog [Roberts et al., JGR, 123, 4381, 2018]. We present the amplitude of the RREA-driving electric field determined using this method on Fermi-GBM data accounting both for tilts of the electric field vector at the TGF source and effects of the atmosphere on photon transport.

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Dates et versions

hal-03563822 , version 1 (10-02-2022)

Identifiants

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Sebastien Celestin, N. Berge, B. Mailyan, M. S. Briggs. Statistical estimation of the electric field amplitude in TGF source regions through the deviation of relativistic electron beams by the geomagnetic field. American Geophysical Union, 2019, San Francisco, United States. ⟨hal-03563822⟩
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