Balloon Observations of Gamma-ray Glows from Thunderstorms

雷暴是由电场和辐射源组成的高能环境。雷暴发出的伽马射线被称为伽马射线发光，通常被闪电终止。然而，对伽马射线发光的观测很少，关于它们是如何产生的，在哪里产生的，以及它们可能如何与闪电的启动有关，人们知之甚少。该项目将结合新的观测和计算机建模，以更好地理解这一现象。该项目的主要方面将是在气球上部署伽马射线传感器，这些气球将被送入雷暴中收集数据。该项目的一个潜在影响是通过提高对闪电引发的理解，这最终可能导致更好的警告和闪电安全。多名学生将参与该项目，从而培养下一代科学家。研究小组将在气球上对伽马射线发光进行观测。这项工作将改进先前设计的气球携带的仪器，该仪器通过结合无机闪烁体和慢速电场测量，使用盖革计数器探测伽马射线发光。在提案期间，计划从佛罗里达州中部起飞30个航班。这些数据以及对伽马射线传播的蒙特卡洛模拟将用于：1)确定伽马射线发光的频率及其与雷暴气象和闪电的关系；2)确定伽马射线辉光的源机制(S)，3)确定源区伽马射线辉光产生的放电电流，4)约束辉光源区域/闪电起始区域中存在的电场和确定闪电之前发生的强场的持续时间，5)确定辉光、闪电和TGFs之间的关系。

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.