GEM: Assessing the Relative Importance of Convection and Induced Electric Fields for Particle Transport and Energization in the Inner Magnetosphere

这个项目调查了磁层中对流和感应电场的重要性，以及它们在环电流和等离子体层动力学中的相对作用。对流电场是由太阳风和地球磁层之间的相互作用产生的。它们大约从黎明到黄昏穿过磁尾，驱动等离子体片离子和电子从磁尾向内磁层移动。在此过程中，对流电场发挥了重要作用，将这些等离子体片粒子激发成高能，并将它们输送到风暴时形成的环电流，即环绕地球的高能离子和电子的环状结构。对流电场在等离子体边界的定位中也起着重要的作用，例如等离子体顶层。等离子体顶是等离子体层陡峭的外边界，等离子体层是由冷的电离层等离子体延伸到内部磁层形成的致密环状结构。这个环向外扩展，占据了旋转电场(磁力线因地球自转而运动而产生的径向电场)主导对流电场的区域。在扰动时期，对流电场相对于基本不变的自旋场增强，减小了自旋场占主导地位的区域。结果，等离子体层的外层区域被剥离，并被对接到日侧磁层顶，在那里等离子体丢失。然而，电场比这两个大尺度电场的叠加要复杂得多。变化的磁场通过感应产生电场。在磁亚暴期间，磁尾磁场的爆炸性重新配置产生了显著的“感应”电场，将较小尺度的时间和空间变异性引入磁层电场。这项提议的主要目标是量化对流电场和感应电场对内部磁层动力学的相对贡献。更全面地了解磁层电场的所有组成部分，对于发展对社会有价值的改进的空间天气预报模式十分重要。该项目为富有成效的女科学家的研究生涯提供支持，为本科生实习生提供研究经验，并为针对K-12学生的年度推广活动提供支持，从而促进未来的科学工作队伍和科学素养。这项研究的主要工具是内部磁层的磁电自洽模型，即赖斯对流模型平衡(RCM-E)。对于风暴事件，测量的内部磁层和电离层的电场将与RCM-E模型的电场进行比较。最初，风暴将在没有显式亚暴磁场变化的情况下进行模拟。RCM-E的磁场、高能离子通量、电子密度和沉淀电子通量将与磁层和电离层卫星的现场测量进行比较。最后，RCM-E地磁风暴模拟的结果将与数据进行比较，以确定感应电场的作用和重要性。

This project investigates the importance of convection and induction electric fields in the magnetosphere, and their relative roles in the dynamics of the ring current and the plasmasphere. Convection electric fields are generated by the interaction between the solar wind and the Earth's magnetosphere. They are directed approximately from dawn to dusk across the magnetotail and drive plasma sheet ions and electrons from the magnetotail towards the inner magnetosphere. Along the way, convection electric fields play an important role in energizing these plasma sheet particles to high energies and in delivering them to build the storm-time ring current, a torus of high-energy ions and electrons surrounding the Earth. Convection electric fields also play an important role in the location of plasma boundaries, such as the plasmapause. The plasmapause is the steep outer boundary of the plasmasphere, a dense torus formed by the extension of cold ionospheric plasma into the inner magnetosphere. This torus expands outward to occupy the region where the corotation electric field (a radial electric field produced by the movement of magnetic field lines in response to Earth's rotation) dominates over the convection electric field. In disturbed times, the convection electric field strengthens with respect to the essentially unchanging corotation field, diminishing the region where the corotation field dominates. As a result, the outer regions of the plasmasphere are stripped away and convected to the dayside magnetopause where the plasma is lost. However, the electric field is more complicated than the superposition of these two large-scale electric fields. Changing magnetic fields produce electric fields through induction. During magnetic substorms, explosive reconfigurations of the magnetotail fields produce significant "induction" electric fields that introduce smaller scale temporal and spatial variability into the magnetospheric electric field. The primary goal of this proposal is to quantify the relative contributions to inner magnetosphere dynamics of convection and induction electric fields. A more complete understanding of all components of the magnetospheric electric field is important for developing improved space weather forecast models of value to society. This project provides support for the research career of a productive female scientist, and a research experience for an undergraduate intern as well as yearly outreach activities aimed at K-12 students, thus contributing to the future scientific workforce and science literacy. The primary tool for this investigation is a magnetically and electrically self-consistent model of the inner magnetosphere, the Rice Convection Model-Equilibrium (RCM-E). For storm events, measurements of the electric fields in the inner magnetosphere and ionosphere will be compared with the modeled RCM-E electric fields. Initially storms will be simulated with no explicit substorm magnetic field changes. The RCM-E magnetic field, energetic ion fluxes, electron densities, and precipitating electron fluxes will be compared with in-situ measurements by magnetospheric and ionospheric satellites. Finally, results of RCM-E geomagnetic storm simulations that incorporate the effects of substorm reconfigurations of the magnetotail fields will be compared with data to determine the role and importance of induced electric fields.