Balloon Observations of Gamma-ray Glows from Thunderstorms

University Of New Hampshire, Durham NH

Investigators

Abstract

Thunderstorms are high-energy environments consisting of electric fields and radiation sources. Gamma-ray emissions from thunderstorms are known as gamma-ray glows and are often terminated by lightning. However, there have been few observations of gamma-ray glows, and little is known about how and where they are created and how they may relate to the initiation of lightning. This project will combine new observations and computer modeling to better understand this phenomena. The main aspect of the project will be the deployment of gamma-ray sensors on balloons that will be flown into thunderstorms to collect data. A potential impact of the project is through the improved understanding of lightning initiation, which may eventually lead to better warnings and lightning safety. Multiple students would be involved in the project, thereby training the next generation of scientists. The research team will conduct balloon-based observations of gamma-ray glows. The work will improve upon a prior design of a balloon-borne instrument that detects gamma-ray glows using Geiger counters by incorporating an inorganic scintillator and a slow electric field measurement. Thirty flights are planned over the course of the proposal period from central Florida. The data, along with Monte Carlo simulations of gamma-ray propagation, would be used to: 1) Determine the frequency of gamma-ray glows and their relationship to thunderstorm meteorology and lightning, 2) Determine source mechanism(s) for gamma-ray glows, 3) Determine discharge currents produced by gamma-ray glows in the source regions, 4) Constrain electric fields present in glow source regions/lightning initiation regions and determine durations of high fields occurring before lightning, 5) Determine relationship between glows, lightning and TGFs.