The lightning-TGF relationship on microsecond timescales
Abstract
We analyze the count rates of two terrestrial gamma-ray flashes (TGFs) detected by the Fermi Gamma-ray Burst Monitor (GBM) with the broadband magnetic fields (1 to 300 kHz) produced by the simultaneous lightning processes. The microsecond-scale absolute time accuracy for these data, combined with independent geolocations of the source lightning, enable this analysis with higher accuracy than previously possible. In both events, fast discharge-like processes occur within several tens of microseconds of the gamma-ray generation, although not with a consistent relationship. The magnetic field data also show a slower signal component produced by a source current that in both events mirrors the gamma-ray count rate closely in shape and time. This indicates electromagnetic radiation directly associated with the gamma-ray generation process and thus provides a new means for probing the internal physics of this enigmatic phenomenon. We will also describe results from a broader analysis of more events and quantify the magnitude of the TGF-associated source current and charge transfer.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMAE24A..01C
- Keywords:
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- 3304 ATMOSPHERIC PROCESSES / Atmospheric electricity;
- 3324 ATMOSPHERIC PROCESSES / Lightning