[MIS20-10] Gamma-ray Observation of Winter Thunderclouds: the progress of multi - point observation in 2019
Keywords:Lightning discharge, Gamma-ray , High-energy atmospheric physics
We are observing gamma-ray events in Hokuriku-regions from 2006. The project is named GROWTH(Gamma-ray Observation of Winter Thunderclouds). We installed 26 gamma-ray detectors in FY 2019. Especially, we installed 20 detectors in Kanazawa City, Ishikawa prefecture within an area of 10 km square at ~ 3 km intervals to track the drift of acceleration area of thunderclouds in detail. In 2019, we newly developed a high-speed readout detector for the detection of downward TGF and the short burst and installed near a tower that lightning is expected. On the coast in Kanazawa City, we installed a directional gamma-ray detector that augmented the lead plate, able to detect direct 10 MeV gamma-ray photons. The purpose of this is to measure the altitude of the acceleration region by using wind velocity. On January 13th, 2020, two long bursts were detected at Izumigaoka and Kindaifuzoku high school in Kanazawa City, Ishikawa prefecture, and these long bursts disappeared in the middle of observation. After we checked lightning data of JLDN(Japanese Lightning Detection Network) and analyzed gamma-ray time data, we confirmed that termination of the two long bursts is coincident with. In addition, we revealed that a TGF/short burst was associated with the lightning discharge. We report mainly on 2020/01/13 events about the result of 2019's winter observation.