AE33A-0476
Ground Level Observations of a Possible Downward-Beamed TGF during a Rocket-Triggered Lightning Flash at Camp Blanding, Florida in August 2014
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Alan Bozarth, Florida Institute of Technology, Melbourne, FL, United States, Joseph R Dwyer, University of New Hampshire Main Campus, Department of Physics, Durham, NH, United States, Eric S Cramer, University of Alabama in Huntsville, Huntsville, AL, United States, Hamid Rassoul, Florida Inst Tech, Melbourne, FL, United States, Martin A Uman, Univ Florida, Gainesville, FL, United States, Douglas Jordan, University of Florida, Ft Walton Beach, FL, United States and J Eric Grove, US Naval Research Laboratory, Washington, DC, United States
Abstract:
Ground level high-energy observations of an August 2014 rocket-triggered lightning event at the International Center for Lightning Research and Testing (ICLRT) in Camp Blanding, Florida show a 180 µs burst of multiple-MeV photons during the latter part of the Upward Positive Leader (UPL) phase of an altitude-triggered lightning flash, following the first, truncated return stroke. The timing and waveform profile being atypical from x-ray emissions from lightning leaders, our observations suggest the occurrence of a downward beamed terrestrial gamma ray flash (TGF). Instrumentation operating during this event include a set of 16 NaI(TI)/PMT detectors plus 7 1-m2 plastic scintillation detectors spread across the 1 km2 facility, with 38 additional Na(TI)/PMT detectors located inside the 1”-thick Pb-shielded x-ray camera and an x-ray spectrometer. Comparing the location and energy data from these detectors to Monte Carlo simulations of TGFs from the REAM code developed by Dwyer [2003], our analysis investigates possible TGF production regions and determines the likelihood of the observed high-energy emissions being produced by a TGF inside the thunderstorm.
