GEM: Study the Precipitation of Radiation Belt Electrons during the Rapid Dropout Events

GEM：研究快速丢失事件期间辐射带电子的沉淀

• 批准号: 1613081
• 负责人: Weichao Tu
• 金额: $ 15.23万
• 依托单位: West Virginia University Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1613081&HistoricalAwards=false
• 关键词: GEM; Study; Precipitation; Radiation; Belt

With the launch of the Van Allen Probes in 2012 a new era in radiation belt studies has begun. This is a project to investigate the scientifically and societally important issue of radiation belt electron dynamics. The emphasis in this research will be on understanding the losses of electrons that occur during magnetic storms. These are significant in that the flux of relativistic electrons decreases by an order of magnitude in a few hours. There are two possible explanations for this: One is loss to the solar wind through the magnetopause and the other is loss to the atmosphere due to precipitation. The former is relatively easy to evaluate but the latter is much more difficult because the loss cone is small in the magnetosphere and because satellite observations provide a limited picture. This proposal will apply a creative approach combining satellite observations from the Van Allen Probes and NOAA POES satellites and a new Drift-Diffusion simulation to quantify the losses. The team will start by determining which observed events are candidates for magnetopause loss, which are candidates for precipitation loss and which are combinations of both types of loss. Then they will use the observations and the simulation iteratively to improve the simulation. They will determine the pitch angle diffusion coefficients as a function of magnetic local time and from that the local time and L shell (radial) dependence of the plasma waves responsible for the precipitation. They will compare this with Van Allen Probes wave observations. They plan a detailed calibration of the POES observations and those from the NSF Colorado Student Space Weather Experiment (CSSWE).Understanding electron dynamics is important societally for understanding space weather. In addition this project will support a young woman scientist and a graduate student. Finally the detailed calibration of the POES and CSSWE data will be useful well beyond this application.

随着2012年范艾伦探测器的发射，辐射带研究的新纪元开始了。这是一个研究辐射带电子动力学的科学和社会重要问题的项目。这项研究的重点将是了解磁暴期间发生的电子损失。这些都很重要，因为相对论电子的流量在几个小时内减少了一个数量级。对此有两种可能的解释：一种是通过磁层顶对太阳风的损失，另一种是降水对大气的损失。前者相对容易评估，但后者则困难得多，因为磁层中的损失锥很小，而且卫星观测提供的图像有限。这项提议将采用一种创造性的方法，将来自Van Allen探测器和NOAA POES卫星的卫星观测与新的漂移-扩散模拟结合起来，以量化损失。该小组将首先确定哪些观测事件是磁层顶损失的候选者，哪些是降水损失的候选者，以及哪些是这两种损失的组合。然后，他们将反复使用观测和模拟来改进模拟。他们将确定俯仰角扩散系数作为磁当地时的函数，并由此确定当地时间和L壳层(径向)与导致降水的等离子体波的关系。他们将把这与范艾伦探测器的波浪观测进行比较。他们计划对POES观测和NSF科罗拉多学生空间天气实验(CSSWE)的观测结果进行详细的校准。了解电子动力学对于理解空间天气具有重要的社会意义。此外，该项目还将资助一名年轻女科学家和一名研究生。最后，POES和CSSWE数据的详细校准将远远超出这一应用的范围。