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| Titel |
Modeling of Pulses in Terrestrial Gamma-ray Flashes |
| VerfasserIn |
Wei Xu, Sebastien Celestin, Victor Pasko |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250106610
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| Publikation (Nr.) |
 EGU/EGU2015-6288.pdf |
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| Zusammenfassung |
| Terrestrial Gamma-ray Flashes (TGFs) are high-energy photon bursts originating from the
Earth’s atmosphere that are associated with lightning activities. After their discovery in 1994
by the Burst and Transient Source Experiment (BATSE) detector aboard the Compton
Gamma-Ray Observatory [Fishman et al., Science, 264, 1313, 1994], this phenomenon has
been further observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager
(RHESSI) [Smith et al., Science, 307, 1085, 2005], the Fermi Gamma-ray Space
Telescope [Briggs et al., JGR, 115, A07323, 2010] and the Astrorivelatore Gamma a
Immagini Leggero (AGILE) satellite [Marisaldi et al., JGR, 115, A00E13, 2010].
Photon spectra corresponding to the mechanism of relativistic runaway electron
avalanches (RREAs) usually provide a very good agreement with satellite observations
[Dwyer and Smith, GRL, 32, L22804, 2005]. On the other hand, Celestin and Pasko
[JGR, 116, A03315, 2011] have shown theoretically that the large flux of thermal
runaway electrons generated by streamers during the negative corona flash stage
of stepping lightning leaders in intracloud lightning flashes could be responsible
for TGFs. Recently, based on analysis of the temporal profiles of 278 TGF events
observed by the Fermi Gamma-Ray Burst Monitor, Foley et al. [JGR, 119, 5931,
2014] have suggested that 67% of TGF pulses detected are asymmetric and these
asymmetric pulses are consistent with the production mechanism of TGFs by relativistic
feedback discharges. In the present work, we employ a Monte Carlo model to study
the temporal distribution of photons at low-orbit satellite altitudes during TGF
events. Using the pulse fitting method described in [Foley et al., 2014], we further
investigate the characteristics of TGF pulses. We mainly focus on the effects of Compton
scattering on the symmetry properties and the rise and fall times of TGF pulses. |
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