Dynamics of the Inner Radiation Belt Near the Trapping Limit

本项目将对地球内辐射带的复杂粒子动力学进行系统研究。它将确定影响辐射带质子含量的几种不同现象的定量效应。这项工作的主要工具将是动力学方程的数值积分，以确定模型磁层场中的质子路径。卫星数据显示，在磁暴期间，内辐射带的~10 MeV辐射带质子大量损失。这些观测结果将对从模拟工作中获得的结果提供严格的检验。将使用影响最显著的简化磁场模型。然后使用详细的磁层模型来计算实际结果。这些模型将通过与观测到的地磁截止变化进行比较来检验。感应电场对径向输运和粒子加速都很重要，它将通过法拉第？S定律在时变磁场模型中的应用。太阳高能质子（sep）注入辐射带是捕获质子的一个重要来源，也已被卫星测量广泛表征。磁暴期间的切断抑制提供了太阳质子进入俘获区。这是否会导致永久捕获，将通过逆转风暴时间损失的数值模拟来评估，以确定质子是否起源于未捕获的太阳质子。这个项目解决了关于内辐射带动力学的一个重要问题。内辐射带中的高能粒子对穿过辐射带的卫星是一个重大的危险。太阳高能质子是影响航天器运行的最重要的危险之一。除了该项目与我们对重要空间天气现象的理解相关外，该项目还具有很强的教育成分，其中大部分研究由研究生进行。

This project will undertake a systematic study of the complex particle dynamics of Earth's innder radiation belt. It will determine the quantitative effects of several different phenomena that can affect the radiation belt proton content. The principal tool in this work will be numerical integration of the dynamical equations to determine proton paths in model magnetospheric fields. Satellite data show significant losses of ~10 MeV radiation belt protons from the inner radiation belt during magnetic storms. These observations will provide stringent tests of the results obtained from the modeling work. Simplified magnetic field models will be used to which effects are most significant. Then detailed magnetospheric models will be used to calculate realistic results. The models will be tested by comparison with observed geomagnetic cutoff variations. Induced electric fields, which are important for both radial transport and particle acceleration, will be determined by application of Faraday?s law in the time dependent magnetic field models. Injections of solar energetic protons (SEPs) into the radiation belt are a significant source of trapped protons and have also been extensively characterized by satellite measurements. Cutoff suppression during magnetic storms provides solar proton access to the trapping region. Whether this can lead to permanent trapping will be assessed by reversing the numerical simulations of storm-time losses to determine if the protons originated in the untrapped solar protons.This project addresses an important question concerning the dynamics of the inner radiation belt. Energetic particles in the inner radiation belt are a significant hazard to satellites that pass through the belt. Solar energetic protons are one of the most important hazards affecting spacecraft operations. In addition to the relevance of the project to our understanding of an important space weather phenomenon, the project has a strong educational component with much of the research being carried out by a graduate student.