Termination of Electron Acceleration in Thundercloud by Intracloud/Intercloud Discharge
Abstract
An on-ground observation program for high-energy atmospheric phenomena in winter thunderstorms along the Japan Sea has been performed via measurements of gamma ray radiation, atmospheric electric field, and low-frequency radio band. On 11 February 2017, the radiation detectors recorded gamma ray emission lasting for 75 s, and then abruptly terminated with a nearby lightning discharge. The gamma ray spectrum extended up to 20 MeV and was reproduced by a cutoff power law model with a photon index of 1.36-0.04+0.03, being consistent with Bremsstrahlung radiation from a thundercloud (known as a gamma-ray glow or a thunderstorm ground enhancement). The low-frequency radio monitors, installed ∼50 km away from the gamma ray observation site recorded leader development of an intracloud/intercloud discharge spreading over ∼60 km area with a ∼300-ms duration. The timing of the gamma ray termination coincided with the moment when the leader development of the intracloud/intercloud discharge passed 0.7 km horizontally away from the radiation monitors. The intracloud/intercloud discharge started ∼15 km away from the gamma ray observation site. Therefore, the glow was terminated by the leader development, while it did not trigger the lightning discharge in the present case.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- June 2018
- DOI:
- 10.1029/2018GL077784
- arXiv:
- arXiv:1805.04721
- Bibcode:
- 2018GeoRL..45.5700W
- Keywords:
-
- gamma ray glow;
- winter thunderstorms;
- atmospheric electric field;
- low frequency;
- electron acceleration;
- Physics - Atmospheric and Oceanic Physics;
- High Energy Physics - Experiment
- E-Print:
- 12 pages, 4 figures, accepted for publication in Geophysical Research Letters