Studying the Optical Emission of Lightning Associated with Terrestrial gamma ray flashes at the Telescope Array Detector

Terrestrial gamma ray flashes (TGF) are emissions of gamma rays in the earth’s atmosphere during thunderstorms. In this investigation, we delve into the optical emissions linked to a TGF observed in 2022. This TGF was observed by the Telescope Array Surface Detector (TASD) in conjunction with lightning detectors including an INTF, a fast antenna, high-speed camera, and a slitless spectroscopic system. The spectrograph recorded images at about 33 μs time resolution with spectral resolution of 2.1 nm per pixel, and spectra range from 400 nm to 900 nm.

This study presents an analysis of the spectra obtained from the lightning flash associated with the TGF. Additionally, preliminary findings from a photometer array, installed at the site in 2023, will be discussed. These photometers share the same field of view as the high-speed video camera and provide higher timing resolution, offering insights into optical emissions from atmospheric electrical discharge processes in the ultraviolet and infrared spectra. This enhanced temporal resolution aims to contribute to the development of conclusive support for the model responsible TGF initiation.

TA & LMA collaboration