Ground-level observation of a terrestrial gamma ray flash initiated by a triggered lightning


Journal Article

© 2016. American Geophysical Union. All Rights Reserved. We report on a terrestrial gamma ray flash (TGF) that occurred on 15 August 2014 coincident with an altitude-triggered lightning at the International Center for Lightning Research and Testing (ICLRT) in North Central Florida. The TGF was observed by a ground-level network of gamma ray, close electric field, distant magnetic field, Lightning Mapping Array (LMA), optical, and radar measurements. Simultaneous gamma ray and LMA data indicate that the upward positive leader of the triggered lightning flash induced relativistic runaway electron avalanches when the leader tip was at about 3.5 km altitude, resulting in the observed TGF. Channel luminosity and electric field data show that there was an initial continuous current (ICC) pulse in the lightning channel to ground during the time of the TGF. Modeling of the observed ICC pulse electric fields measured at close range (100-200 m) indicates that the ICC pulse current had both a slow and fast component (full widths at half maximum of 235 µs and 59 µs) and that the fast component was more or less coincident with the TGF, suggesting a physical association between the relativistic runaway electron avalanches and the ICC pulse observed at ground. Our ICC pulse model reproduces moderately well the measured close electric fields at the ICLRT as well as three independent magnetic field measurements made about 250 km away. Radar and LMA data suggest that there was negative charge near the region in which the TGF was initiated.

Full Text

Duke Authors

Cited Authors

  • Hare, BM; Uman, MA; Dwyer, JR; Jordan, DM; Biggerstaff, MI; Caicedo, JA; Carvalho, FL; Wilkes, RA; Kotovsky, DA; Gamerota, WR; Pilkey, JT; Ngin, TK; Moore, RC; Rassoul, HK; Cummer, SA; Grove, JE; Nag, A; Betten, DP; Bozarth, A

Published Date

  • January 1, 2016

Published In

Volume / Issue

  • 121 / 11

Start / End Page

  • 6511 - 6533

Electronic International Standard Serial Number (EISSN)

  • 2156-2202

International Standard Serial Number (ISSN)

  • 0148-0227

Digital Object Identifier (DOI)

  • 10.1002/2015JD024426

Citation Source

  • Scopus