Gamma-ray glow preceding downward terrestrial gamma-ray flash
Résumé
Two types of high-energy events have been detected from thunderstorms.One is "terrestrial gamma-ray flashes" (TGFs), sub-millisecond emissionscoinciding with lightning discharges. The other is minute-lasting"gamma-ray glows". Although both phenomena are thought to originate fromrelativistic runaway electron avalanches in strong electric fields, theconnection between them is not well understood. Here we reportunequivocal simultaneous detection of a gamma-ray glow termination and adownward TGF, observed from the ground. During a winter thunderstorm inJapan on 9 January 2018, our detectors caught a gamma-ray glow, whichmoved for 100 s with ambient wind, and then abruptly ceased with alightning discharge. Simultaneously, the detectors observed photonuclearreactions triggered by a downward TGF, whose radio pulse was locatedwithin 1 km from where the glow ceased. It is suggested that the highly-electrified region producing the glow was related to the initiation ofthe downward TGF.