title: Radio emissions from double RHESSI TGFs.
abstract: A detailed analysis of Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) terrestrial gamma ray flashes (TGFs) is performed in association with World Wide Lightning Location Network (WWLLN) sources and very low frequency (VLF) sferics recorded at Duke University. RHESSI clock offset is evaluated and found to experience changes on the 5 August 2005 and 21 October 2013, based on the analysis of TGF-WWLLN matches. The clock offsets were found for all three periods of observations with standard deviations less than 100 μs. This result opens the possibility for the precise comparative analyses of RHESSI TGFs with the other types of data (WWLLN, radio measurements, etc.) In case of multiple-peak TGFs, WWLLN detections are observed to be simultaneous with the last TGF peak for all 16 cases of multipeak RHESSI TGFs simultaneous with WWLLN sources. VLF magnetic field sferics were recorded for two of these 16 events at Duke University. These radio measurements also attribute VLF sferics to the second peak of the double TGFs, exhibiting no detectable radio emission during the first TGF peak. Possible scenarios explaining these observations are proposed. Double (multipeak) TGFs could help to distinguish between the VLF radio emission radiated by the recoil currents in the +IC leader channel and the VLF emission from the TGF producing electrons.
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors: Andrew
authors: A
authors: Mezentsev
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors: Nikolai
authors: N
authors: Østgaard
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway; Department of Engineering Sciences University of Agder Grimstad Norway.
authors: Thomas
authors: T
authors: Gjesteland
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors: Kjetil
authors: K
authors: Albrechtsen
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway.
authors: Nikolai
authors: N
authors: Lehtinen
authors: Birkeland Centre for Space Science, Department of Physics and Technology University of Bergen Bergen Norway; INAF-IASF National Institute for Astrophysics Bologna Italy.
authors: Martino
authors: M
authors: Marisaldi
authors: Department of Physics, Santa Cruz Institute for Particle Physics University of California Santa Cruz California USA.
authors: David
authors: D
authors: Smith
authors: Electrical and Computer Engineering Department Duke University Durham North Carolina USA.
authors: Steven
authors: S
authors: Cummer
keywords: RHESSI TGFs; RHESSI clock offset; TGF‐WWLLN match; multipeak TGFs; radio emission from TGF; terrestrial gamma ray flashes