Collaborative Research: GEM--The Effect of Magnetosonic Waves on Energetic Electrons in the Earth's Magnetosphere

该项目旨在解决地球磁场（磁层）中带电粒子，特别是电子上的电磁波。由于辐射带电子对空间系统的潜在危害，该工作对改进辐射带电子的建模和预测具有重要的现实意义。具体而言，辐射危害通过航天器表面和内部充电对航天器产生破坏性影响。这项研究的目的是促进我们对内磁层和辐射带动力学的基本物理过程的理解。研究结果将用于提高当前辐射带的模拟能力。该项目还支持两名早期职业科学家和一名博士生。该项目的研究成果将被纳入德克萨斯大学达拉斯分校首席研究员正在开发的磁层物理学新入门课程中。本项目采用观测和模拟相结合的方法，对赤道磁声波（MS）对内磁层高能电子动力学的影响进行了定量研究。由于质谱波具有通过朗道共振加速电子的潜在机制，以及通过反射共振散射赤道镜像电子，因此越来越受到研究界的关注。最近的Van Allen探针观测揭示了与MS波相关的电子蝴蝶分布的形成，以及MS波对电子俯仰角分布的原位调制。赤道镜像电子的动力学是一个重要的科学问题，目前还没有在辐射带模型中实现。该项目将解决三个基本的科学问题：MS波与内磁层电子蝴蝶俯仰角分布之间的关系是什么？电子输运系数如何依赖于磁声波法向和波谱以及背景等离子体参数？如何将弹跳共振效应纳入模型？为了解决这些问题，将对双范艾伦探测器的高分辨率波和粒子测量结果进行分析。实验粒子模拟将计算电子输运系数作为俯仰角和能量的函数，然后对这些输运系数进行参数化研究。将模拟MS波引起的相空间密度演变，并与Van Allen探测器的高分辨率电子俯仰角分布进行比较。

This project aims to address the electromagnetic waves in Earth's magnetic field (magnetosphere) on charged particles, electrons specifically. This work is timely and highly relevant for improving the modeling and prediction of radiation belt electrons, which are of considerable practical importance due to their potential hazards to space systems. Specifically, radiation hazards have damaging effects on spacecraft through surface and internal charging. The research is directed towards advancing our understanding of the fundamental physical processes in the inner magnetosphere and dynamics of the radiation belt. The results will be utilized to improve current radiation belt modeling capabilities. This project also supports two early career scientists and a doctoral student. The findings of this project will be incorporated into a new introductory course in magnetospheric physics that the lead Principal Investigator is developing at University of Texas-Dallas .This project is a unified investigation, taking advantage of both observations and modeling, to quantify the effect of equatorial magnetosonic (MS) waves on energetic electron dynamics in the inner magnetosphere. MS waves have gained an increasing amount of attention in the research community, due to their potential mechanism for electron acceleration via Landau resonance, and their scattering of equatorially mirroring electron via bounce resonance. Recent Van Allen Probes observations have revealed the formation of electron butterfly distributions associated with MS waves, and in-situ modulation of the electron pitch angle distribution by the MS waves. The dynamics of equatorially mirroring electrons is important scientific question, which currently is not implemented in radiation belt models. This project will address the three fundamental scientific questions: What is the relation between MS waves and the electron butterfly pitch angle distribution in the inner magnetosphere? How do electron transport coefficients depend on magnetosonic wave normal and wave spectra and background plasma parameters? And how can bounce resonance effects be incorporated into models? To address these questions, high-resolution wave and particle measurements from the twin Van Allen Probes will be analyzed. Test particle simulations will be carried out to calculate the electron transport coefficients as a function of pitch angle and energy, and then perform a parametric study of those transport coefficients. Phase space density evolution due to MS waves will be modelled and compared with high-resolution electron pitch angle distributions from Van Allen Probes.