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| Titel |
Observations of a Terrestrial Gamma Ray Flash at ground level coincident with a current pulse on a triggered lightning channel |
| VerfasserIn |
Brian Hare, Martin Uman, Joseph Dwyer, Douglas Jordan, Jaime Caicedo, Felipe Carvalho, Robert Wilkes, Daniel Kotovsky, William Gamerota, John Pilkey, Terry Ngin, Robert Moore, Steve Cummer, Eric Grove, Amitabh Nag, Michael Biggerstaff, Daniel Betten, Alan Bozarth, Hamid Rassoul |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250139252
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| Publikation (Nr.) |
 EGU/EGU2017-2449.pdf |
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| Zusammenfassung |
| We report on a second terrestrial gamma ray flash (TGF) detected at ground-level coincident
with a rocket-triggered lightning flash. The second TGF was observed in August
2014, while the first was detected in August 2003 and reported by Dwyer et. al.
[2004]. Both TGFs occurred during the initial stage of the associated triggered
lightning flashes and both TGFs were coincident with large pulses of current on the
lightning channel. Modeling of the current pulse from the 2014 TGF and direct
measurement of the 2003 pulse indicates that the current pulses during both TGFs had very
similar shapes and that each current pulses consisted of two superimposed Gaussian
shaped currents. Current measured at the base of the lightning channel in 2003
shows that the two Gaussian current waves had full widths at half maximum of
765 μs and 75 μs, and modeling of electric fields measured in 2014 show that the
two Gaussian currents in 2014 had full widths at half maximums of 235 μs and 59
μs. Lightning mapping array data collected during the 2014 TGF indicates that
the TGF was initiated when the triggered lightning upward positive leader (UPL)
reached an altitude of 3.5 km altitude. A comparison between this altitude and
the current modeling shows that the TGF was initiated after the beginning of the
longer Gaussian current but suggests that peak TGF flux and peak current amplitude
occurred at about the same time at the tip of the UPL, suggesting that the faster
Gaussian current and the TGF could have been produced by the same physical source. |
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