GEM: Solar Wind Entry into the Magnetospohere and Its Paths to the Plasma Sheet

太阳风的等离子体是如何以及在哪里进入地球磁层的，这在很大程度上仍然未知。该项目将结合最先进的全球混合（动态离子，流体电子）模拟和与航天器数据的比较来解决这个问题。该项目分为两个阶段。第一个是关于等离子体进入昼侧磁层顶的磁层，而第二个是关于发生在磁尾侧翼的现象，以及将入射太阳风等离子体转移到等离子体层的过程。最初，重点将放在稳定和非稳定太阳风条件下弓形激波、离子前激波和磁鞘对日侧输运的影响等问题上。低纬度（LLBL）和高纬度（HLBL）边界层的形成及其结构将被研究。接下来，将跟踪边界层等离子体的输运，以评估其对等离子体片种群的贡献。此外，将研究通过尾叶和侧翼直接进入等离子体片的机制。拟议的建模和航天器数据分析活动旨在利用每种方法的优势，并实现协同作用，从而了解太阳风进入磁层及其进入等离子层的路径。由于解决了离子的时间和空间尺度，全局混合模拟特别适合于解决等离子体输运问题，如重连接和波粒相互作用或局部与非局部过程的相对重要性。除了基本的等离子矩（密度，流速等），混合模拟将提供整个磁层的离子速度分布函数。离子的动力学处理使得研究磁层顶的质量过滤效应和以自洽的方式追踪离子的轨道成为可能。

How and where plasma from the solar wind enters Earth's magnetosphere is still largely unknown. This project will use a combination of state-of-the-art global hybrid (kinetic ions, fluid electrons) simulations and comparison with spacecraft data to address this problem. The project has two phases. The first concerns the entry of plasma into the magnetosphere on the dayside magnetopause, while the second concerns phenomena that occur on the magnetotail flanks and the processes that transfer incoming solar wind plasma into the plasma sheet. Initially, the focus will be on issues such as the influences of the bow shock, ion foreshock and magnetosheath on dayside transport during steady and non-steady solar wind conditions. Formation of low latitude (LLBL) and high latitude (HLBL) boundary layers and their structure will be investigated. Next, the transport of the boundary layer plasma will be followed to assess its contributions to the plasma sheet population. In addition, direct entry mechanisms into the plasma sheet through the tail lobes and flanks will be investigated. The proposed modeling and spacecraft data analysis activities are designed to take advantage of the strength of each approach and achieving a synergy that will lead to an understanding of solar wind entry into the magnetosphere and its paths to the plasma sheet. By virtue of resolving ion temporal and spatial scales, global hybrid simulations are uniquely suited for addressing plasma transport questions such as the relative significance of reconnection and wave-particle interactions or local vs. non-local processes. In addition to the basic plasma moments (density, flow speed etc.), hybrid simulations will provide ion velocity distribution functions throughout the magnetosphere. The kinetic treatment of ions makes it possible to investigate mass filtering effects at the magnetopause and to trace the orbit of ions in a self consistent manner.