CEDAR: Mechanisms and Effects of Terrestrial Gamma-Ray Flashes

CEDAR：地面伽马射线闪光的机制和影响

• 批准号: 0535461
• 负责人: John Gill
• 金额: --
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0535461&HistoricalAwards=false
• 关键词: CEDAR; Mechanisms; Effects; Terrestrial; Gamma

A 3-year theoretical investigation of the mechanisms and effects of Terrestrial Gamma-ray Flashes (TGFs) will be carried out under this grant. Recent observations of TGFs from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) spacecraft have demonstrated the need for a revision of the current model for their generation. This project will investigate a new mechanism for the production of TGFs based on the possibility for production of runaway electron avalanche driven by electromagnetic impulses (EMP) radiated by rapidly moving lightning return strokes. The proposed program builds on previous models of TGF production developed by the proposing team and the main objective is to determine the quantitative feasibility of the EMP-driven mechanism. This includes the development of a kinetically based Monte Carlo model of the partially synchronized runaway acceleration of relativistic electrons by the lightning EMP. In addition, model results will be compared to experimental data, including TGF fluxes and energy spectra as observed on RHESSI.This project is cross-disciplinary in that it will advance understanding of the electrodynamic coupling between the lower (neutral) atmosphere, where thunderstorms occur, and the higher altitude ionized layers of the mesosphere and the ionosphere. In addition, relativistic runaway acceleration is a fundamentally new particle acceleration phenomenon and the results of this research project, therefore, will have broader scientific impact beyond atmospheric sciences.

这笔赠款将针对地面伽马射线闪光（TGF）的机制和影响进行为期三年的理论研究。最近从拉马蒂高能太阳光谱成像仪（RHESSI）航天器对 TGF 的观测表明，有必要对其生成的当前模型进行修订。该项目将研究一种生产 TGF 的新机制，该机制基于快速移动的闪电回击辐射的电磁脉冲 (EMP) 驱动的失控电子雪崩的产生可能性。拟议的计划建立在提案团队开发的先前 TGF 生产模型的基础上，主要目标是确定 EMP 驱动机制的定量可行性。这包括开发基于动力学的蒙特卡罗模型，该模型用于描述闪电电磁脉冲对相对论性电子的部分同步失控加速。此外，模型结果将与实验数据进行比较，包括在 RHESSI 上观察到的 TGF 通量和能谱。该项目是跨学科的，因为它将促进对发生雷暴的低层（中性）大气之间的电动耦合的理解，以及中间层和电离层的更高海拔电离层。此外，相对论失控加速是一种全新的粒子加速现象，因此该研究项目的结果将产生大气科学之外更广泛的科学影响。