![]() ![]() In this work, we show that, while TGFs pass through the atmosphere, the large quantities of energetic electrons knocked out during collisions of gamma-rays with air molecules can generate significant amount of excited species of neutral and ionized nitrogen molecules, thereby leading to production of a new type of transient luminous events (TLEs). Moreover, detailed analyses of radio emissions have pointed out the close correlation between TGFs and the initial development stages of normal polarity intra-cloud lightning that transports negative charge upward (+IC). ![]() Space-borne measurements have revealed the temporal and spectral features of TGFs: typically lasting from fractions of to a few milliseconds, having a fluence of fractions of photons/cm2, and exhibiting a hard energy spectra extending up to a few tens of MeVs. Since the discovery, TGFs have also been observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), the Fermi Gamma-ray Space Telescope, and the Astrorivelatore Gamma a Immagini Leggero (AGILE) satellite. A.ĭiscovered in 1994 by the Burst and Transient Source Experiment (BATSE) detector aboard the Compton Gamma-Ray Observatory, Terrestrial Gamma-ray Flashes (TGFs) are high-energy photon bursts originating from the Earth's atmosphere characterized by their close association with thunderstorm activities. Since the spectroscopic, morphological, and temporal features of this luminous event are closely related with TGFs, corresponding measurements would provide a novel perspective for investigation of TGFs, as well as lightning discharges that produce them.Ī New Type of Transient Luminous Events Produced by Terrestrial Gamma-ray Flashes We show that this predicted phenomenon illuminates a region with a size notably larger than the TGF source and has detectable levels of brightness. These emissions represent a novel type of transient luminous events in the vicinity of the cloud tops. In this paper, we demonstrate theoretically that, while TGFs pass through the atmosphere, the large quantities of energetic electrons knocked out by collisions between photons and air molecules generate excited species of neutral and ionized molecules, leading to a significant amount of optical emissions. Terrestrial Gamma-ray Flashes (TGFs), discovered in 1994 by the Compton Gamma-Ray Observatory, are high-energy photon bursts originating in the Earth's atmosphere in association with thunderstorms. Xu, Wei Celestin, Sebastien Pasko, Victor P. A novel type of transient luminous event produced by terrestrial gamma-ray flashes ![]()
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