Rare TGFs and common glows: a systematic survey of data from the first flights of ADELE
Abstract
The Airborne Detector for Energetic Lightning Emission (ADELE) is a mobile array of gamma and x-ray detectors meant to study radiation associated with thunderstorms. ADELE flew aboard a Gulfstream V jet near the tops of Florida thunderstorms in summer of 2009, performing the first systematic search for Terrestrial Gamma-ray Flashes (TGFs) at aircraft altitudes. We use GEANT3 simulations of electron and gamma-ray propagation in Earth's atmosphere and our instrument to show that ADELE was within the range of detection for TGFs from numerous lightning flashes but only saw one TGF event (see the companion presentation by Lowell et al.). This allows us to place strong upper limits on TGF emission from IC, +CG, and -CG lightning, demonstrating that TGFs are a rare phenomenon in lightning in this region, and cannot be the primary triggering mechanism for most lightning. The ADELE campaign also observed "glows" of high-energy radiation over several clouds. We shall also report the frequency of the occurrence of glows during our Florida 2009 campaign. On one occasion, the glow lasted through two passes of the aircraft over the same cell. This glow may represent the relativistic runaway feedback process continuously limiting the total charging of the cell, showing that this mechanism may compete with discrete lightning discharges as the main charge-limiting process in storms.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMAE11A0332K
- Keywords:
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- 3304 ATMOSPHERIC PROCESSES / Atmospheric electricity;
- 3324 ATMOSPHERIC PROCESSES / Lightning