Constraining Spectral Models of a Terrestrial Gamma?Ray Flash From a Terrestrial Electron Beam Observation by the Atmosphere?Space Interactions Monitor

Terrestrial Gamma ray Flashes (TGFs) are short flashes of high energy photons, produced by thunderstorms. When interacting with the atmosphere, they produce relativistic electrons and positrons, a part gets bounded to geomagnetic field lines travels large distances in space. This phenomenon is called Electron Beam (TEB). The Atmosphere-Space Interactions Monitor (ASIM) mounted on-board International Space Station detected new TEB event on March 24, 2019, originating from tropical cyclone Johanina. Using ASIM's low detector, spectrum resolved down 50 keV. We provide method constrain TGF source based spectrum. Applied this event, it shows that only fully developed Relativistic Runaway Avalanche spectra compatible observation. More specifically, assuming , models have ? ? 6.5 MeV (E photon cut-off energy). could not exclude 8 10 MeV.