CEDAR: Mechanisms and Effects of Terrestrial Gamma-ray Flashes

该项目由2009年美国复苏和再投资法案（Public Law 111-5）资助。该项目对地球伽马射线闪光（TGF）的产生机制和特性进行理论研究。 调查将包括完整的闪电和雷暴模型，甚低频无线电波观测，甚低频波传播建模，高能粒子行为的蒙特卡罗模拟以及卫星数据分析。此外，新的电场测量技术将在TGF排放的背景下开发和评估。 将在卫星数据中搜寻电子或低能光子发射，这将提供关于观测到的发射的信息，包括其地理位置。 甚低频波观测，加上闪电建模和卫星TGF观测，将产生额外的地理位置以及源闪电的动态信息。 要解决的特定主题包括闪电在驱动电场生产中的作用以及地理和天气条件对TGF发生的影响。 该项目将通过对地面伽马射线闪光进行观测和建模研究，帮助量化低层大气、电离层和磁层之间的电动耦合。 该项目包括开发一种测量雷暴上空电场的新技术和雷电过程的新模型。本科生将通过斯坦福大学的本科生研究经验参与该项目。 他们将由研究生指导，为他们提供额外的教育经验以及研究和工程机会。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project undertakes theoretical investigation of the production mechanisms and properties of terrestrial gamma-ray flashes (TGF). The investigation will include full lightning and thunderstorm models, very low frequency radio wave observations, very low frequency wave propagation modeling, Monte Carlo simulations of energetic particle behavior, and analysis of satellite data. In addition, new electric field measurement techniques will be developed and evaluated in the context of TGF emissions. The satellite data will be searched for electron or low-energy photon emissions, which would provide information on the observed emissions, including their geolocations. Very low frequency wave observations, coupled with lightning modeling and satellite TGF observations, will yield additional geolocations as well as information on the dynamics of the source lightning. Particular topics to be addressed include the role of lightning in production of the driving electric fields and the effects of geographic and weather conditions on TGF occurrence. The project will help quantify the electrodynamic coupling between the lower atmosphere, the ionosphere, and the magnetosphere by performing an observational and modeling study focused on terrestrial gamma ray flashes. The project includes the development of a new technique to measure electric fields above thunderstorms and new models of lightning processes. Undergraduates will participate in the project through Stanford University's Research Experience for Undergraduates. They will be mentored by graduate students, providing them with additional educational experience as well as research and engineering opportunities.