Exploring the Potential of Aerial and Balloon-Based Observations in the Study of Terrestrial Gamma Ray Flashes

Abstract. Recently presented measurements of Terrestrial Gamma Ray Flashes (TGF) above thunderstorms onboard aircraft and weather balloons introduce viable alternatives which could help to overcome limitations inherent in satellite-based observations, such as significant gamma ray attenuation by the atmosphere. This study explores the potential and implications of measuring TGFs using aircraft and weather balloons. Utilizing Monte Carlo simulations with the MCNP6 tool, the spatial distributions, fluences, and energy spectra of photons, electrons, and neutrons generated by TGFs are assessed at altitudes of 5 to 50 km. Results indicate that TGFs originating at lower altitudes produce narrower beams compared to those at higher altitudes, suggesting that weather balloons may be more effective for high-altitude TGFs, such as those associated with summer thunderstorms or thunderstorms in tropical regions. Whereas staffed aircraft might be more suitable for low altitude TGFs originating in temperate regions or in winter thunderstorms. Photon and electron energy spectra features, including maximum energy, and the presence of 511 keV photons, can help estimate the radial distance from the TGF axis. Expected photon fluences from TGFs range from 1 to 10,000 cm^-2, with electron fluences ranging from 1 to 1,000 cm^-2, depending on the TGF's brightness. Neutron fluences are notably lower, up to 10 cm^-2. These findings underscore the potential of aerial and balloon-based measurements to provide critical insights into TGFs and their detection, addressing the limitations of current satellite observations.