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

随着2012年范艾伦探测器的发射，辐射带研究的新时代已经开始。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。这项研究的重点是了解磁暴期间发生的电子损失。这是很重要的，因为相对论电子的通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：一种是通过磁层顶损失到太阳风中，另一种是由于降水损失到大气中。前者比较容易评估，而后者则困难得多，因为磁层中的损耗锥很小，而且卫星观测提供的图像有限。该提案将采用一种创造性的方法，将范艾伦探测器和NOAA POES卫星的卫星观测与一种新的漂移扩散模拟相结合，以量化损失。研究小组将首先确定哪些观测到的事件是磁层顶损失的候选者，哪些是降水损失的候选者，哪些是两种损失的组合。然后，他们将使用观察和模拟迭代来改进模拟。他们将确定作为磁局部时间函数的俯仰角扩散系数，并由此确定引起沉淀的等离子体波的局部时间和L壳（径向）依赖关系。他们将把这与范艾伦探测器的波观测结果进行比较。他们计划对POES观测结果和来自美国国家科学基金会科罗拉多学生空间天气实验（CSSWE）的观测结果进行详细校准。理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此应用范围。

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.