A numerical study on TGFs and relativistic feedback discharges

Terrestrial gamma-ray flashes are sub-millisecond bursts of >1 MeV photons originating from thunderclouds in the earth´s atmosphere [e.g., Fishman et al., Science, 264, 1313, 1994]. They are normally produced in the initial stage of positive intra-cloud lightning discharges [e.g., Shao et al., JGR, 115, A00E30, 2010; Lu et al., GRL, 37, L11806, 2010; Cummer et al., GRL, 38, L14810, 2011]. In addition to the relatively short TGFs, thunderclouds and lightning can also make minute long gamma-ray glows according to ground-based [e.g., Chilingarian et al., PRD, 82, 043009, 2010] and airborne measurements [e.g., Smith et al., JGR, 116, D20124, 2011].