A research group including Associate Professor Kazuhiro Nakazawa, KMI, Nagoya University has observed high-energy radiation phenomena coming from thunder-clouds, and found a prolonged steady emission resulted in a short burst of radiation associated with a lightning discharge. The evolution of the phenomena strongly suggests the initial long emission is related with the triggering of the lightning.

The research group was performing ground-based gamma-ray observation campaign aiming at winter thunder-clouds in Hokuriku-region. In the work, they observed a minute-long radiation from the cloud on 10/Jan./2018. The phenomena were followed by a bright flash of radiation and a lightning discharge. This is the first timing and positional coincidence between the long-duration radiation and the short flash and discharge are confirmed.

This work is supported by Kanazawa University senior high school, Kanazawa-Izumigaoka high school and other high schools, universities, companies, Kanazawa and Komatsu city and Toyama prefecture. The work is supported from one of the first academic crowdfunding in Japan, and therefore collaborating with local high school students or citizens. Ass. Prof. Nakazawa contributed to detector development and data analysis. This research is published in Communications Physics on June 25, 2019.

This is one of the rewarding results of a fruitful collaboration making Japan the top runner in this emerging hot science field. The radiation was very strong, and it coincidence with lightning discharge indicated deep relation between them. With Nagoya/KMI contributing to further enhancing the observation campaign, as well as big effort of all the team members, more and more interesting results will follow. — Kazuhiro Nakazawa

Press Release

Press Release Article (UTokyo) 

Paper Information

Journal: Communications Physics (June 25, 2019, online)
Title: “Gamma-ray Glow preceding Downward Terrestrial Gamma-ray Flash”
Authors: Yuuki Wada*, Teruaki Enoto, Yoshitaka Nakamura, Yoshihiro Furuta, Takayuki Yuasa, Kazuhiro Nakazawa, Takeshi Morimoto, Mitsuteru Sato, Takahiro Matsumoto, Daisuke Yonetoku, Tatsuya Sawano, Hideo Sakai, Masashi Kamogawa, Tomoo Ushio, Kazuo Makishima, Harufumi Tsuchiya
DOI: 10.1038/s42005-019-0168-y
Link: https://www.nature.com/articles/s42005-019-0168-y