GEM: Multipoint Observations and Global Modeling of Energetic Particle Deep Penetration into the Low L Region of Earth's Inner Magnetosphere

了解地球周围的相对论粒子环境对于预测和减轻空间天气影响至关重要。这些影响包括对近地轨道卫星的破坏。该项目通过观测研究和最先进的建模相结合，解决了粒子如何在内磁层加速的重要问题。支持两名早期职业研究人员。该项目的主要目标是利用范艾伦探测器和THEMIS的数据，以及RCM-E和三维粒子示踪剂的建模，研究和量化电场在高能电子和质子深度穿透中的作用。需要解决的具体科学问题是：1)基于多点观测，高能电子和质子深度穿透低L区在穿透深度、频率、时间和MLT分布等方面的定量差异是什么？2)基于多点观测，高能粒子深穿事件发生时，内磁层电场的时空演化特征是什么？3) RCM-E在多大程度上能代表深穿事件中观测到的内磁层电场？4) RCM-E给出的电场在多大程度上可以解释不同种类和/或能量的内磁层高能粒子深度穿透的差异？为了回答这些科学问题，将使用范艾伦探测器的数据确定L4以下的高能粒子深度穿透事件，并检查穿透深度，时间和MLT依赖性。研究了范艾伦探测器上的EFW和THEMIS上的EFI的电场测量结果，并对电场的时空演变进行了研究。RCM-E将用于模拟自洽的、随时间变化的内磁层电场，以便与观测结果进行比较。然后将模拟的电场嵌入到粒子示踪剂中，以检验观察到的高能粒子深度穿透，特别是电子和质子穿透之间的差异，是否可以用RCM-E模拟电场对内磁层居群的输运来解释。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding the relativistic particle environment surrounding Earth is vital to predict and mitigate space weather effects. These effects include damage to satellites in low-Earth orbit. This project addresses an important question of how particles are accelerated in the inner magnetosphere through a combination of observational studies and state-of-the-art modeling. Two early career researchers are supported.The main goal of this project is to investigate and quantify the role of electric fields in the deep penetration of energetic electrons and protons using data from the Van Allen Probes and THEMIS as well as modeling with the RCM-E and a 3-D particle tracer. Specific science questions to be addressed are: 1) Based on the multipoint observations, what are the quantitative differences between energetic electron and proton deep penetration into the low L region in penetration depth, frequency, timing, and MLT distribution? 2) Based on the multipoint observations, what is the spatiotemporal evolution of electric fields in the inner magnetosphere during energetic particle deep penetration events? 3) To what extent can the RCM-E represent the observed electric fields in the inner magnetosphere during deep penetration events? 4) To what extent can the electric fields given by RCM-E explain the differences in deep penetration of inner magnetospheric energetic particles of different species and/or energies? To answer these science questions, energetic particle deep penetration events down to L4 will be identified using data from the Van Allen Probes, and the penetration depth, timing, and MLT dependence will be examined. The electric field measurements from EFW on Van Allen Probes and EFI on THEMIS will be examined, and the spatiotemporal evolution of electric fields will be investigated. The RCM-E will be used to model self-consistent, time-varying electric fields in the inner magnetosphere to be compared to the observations. The modeled electric fields will then be embedded into a particle tracer to examine whether the observed energetic particle deep penetration, especially the differences between electron and proton penetration, can be explained by the transport of inner magnetospheric populations by the modeled electric field of RCM-E.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.