Radio emissions from double RHESSI TGFs. Issue 13 (14th July 2016)

• Record Type: Journal Article
• Authors: Mezentsev, Andrew; Østgaard, Nikolai; Gjesteland, Thomas; Albrechtsen, Kjetil; Lehtinen, Nikolai; Marisaldi, Martino; Smith, David; Cummer, Steven
• Is Part Of: Journal of geophysical research. Volume 121:Issue 13(2016)
• Page Start: 8006
• Page End: 8022
• Publication Date: 2016-07-14
• Subjects: terrestrial gamma ray flashes -- multipeak TGFs -- RHESSI TGFs -- RHESSI clock offset -- TGF‐WWLLN match -- radio emission from TGF; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2016JD025111
• Languages: English
• ISSNs: 2169-897X

Abstract

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. Key Points: RHESSI clock offsets are determined for three observation periods In case of double TGFs, radio signals are observed simultaneously with the second TGF peak Double (multipeak) TGFs may provide the opportunity to distinguish which VLF pulses are associated with TGF production