[M-IS19] Atmospheric electricity and application of technology for reducing disaster risks

[MIS19-10] Lifecycle observation of gamma-ray glows by tracking thunderclouds

*Yuuki Wada¹, Ting Wu², Masashi Kamogawa³, Daohong Wang², Go Okada⁴, Hidehito Nanto⁴, Tatsuya Sawano⁵, Mamoru Kubo⁵, Daisuke Yonetoku⁵, Gabriel Sousa Diniz⁶, Harufumi Tsuchiya⁷ (1.Osaka Univ., 2.Gifu Univ., 3.Univ. of Shizuoka, 4.Kanazawa Institute of Technology, 5.Kanazawa Univ., 6.National Institute for Space Research, 7.JAEA)

Keywords:gamma-ray glow, high-energy atmospheric physics, electron acceleration, thundercloud

Gamma-ray glows are thought to originate from electron acceleration in the strong electric field region in a thundercloud, and are typically detected for tens of seconds to minutes. Therefore, the generation and development of gamma-ray glows are closely related to the generation and development of the strong electric field region in a thundercloud. However, observations at a single site were unable to separate the development of the gamma-ray glow from the effects of the thundercloud movement, unable to capture the life cycle of a gamma-ray glow. We observed two gamma-ray glows with four gamma-ray detectors installed in Kanazawa City and Nonoichi City, Ishikawa Prefecture. The first gamma-ray glow was quenched with a lightning discharge, and hence the glow ended when the electric field was neutralized by the lightning discharge. The second glow reoccurred in the area of the thundercloud where the first glow occurred, and was detected by three detectors downwind 2-3 minutes after the lightning discharge. However, the detection time of the second glow by the three detectors does not match the movement of the thundercloud observed by the radar, which contradicts the picture of gamma-ray glows in which a thundercloud passes over the detectors while emitting gamma rays with a constant intensity. Furthermore, the second glow occurred again within a few minutes in the area neutralized by the lightning discharge. These observations suggest that the strong electric field that caused the second gamma-ray glow developed rapidly above the three detectors. In fact, the radar observed a strong echo area descending, and it is highly likely that the second glow developed rapidly in response to the descending echo.