GEM: Influence of the Plasma Sheet Density, Temperature, and Local Time Asymmetry on the Ring Current Strength and Peak Location

在磁层的近地尾部既可以观察到冷密度等离子体，也可以观察到热稀薄等离子体。已知在向北的行星际磁场(IMF)间隔期间形成冷密度等离子体片(CDPS)，并且主要源于太阳风。在非向北的IMF条件下，通常可以观察到热-纤细的等离子体片，并且通常包含较重离子(主要是O+)的较大贡献。在磁活动期间，这两种类型的布居都是环电流的来源。最近的观测也表明，稠密的等离子体从等离子体片边界层(PSBL)的黎明侧输运，但这种等离子体的性质及其对环电流形成的潜在影响还没有得到详细的研究。本项目讨论等离子体片的性质和向等离子体片和PSBL粒子的内磁层和环电流区的传输，以便以系统的方式评估等离子体片密度、温度和当地时间不对称性对磁暴强度的作用。它旨在回答下列科学问题：(A)等离子体片和边界层等离子体如何以及在哪里进入内磁层/环电流区？(B)等离子体片性质(密度、温度和当地时间不对称性)对质子环电流强度和峰位有什么影响？该研究项目将结合主要的磁层和太阳风科学飞行任务(星系团、洛斯阿拉莫斯地球同步仪器)的数据和使用环电流动力学模型的模拟结果来处理这些问题。这项研究还将有助于实现一个教育目标。洛斯阿拉莫斯大学开展了一项本科生研究项目，预计将有一名或多名学生参与这一项目。

Both cold-dense and hot-tenuous plasmas are observed in the near-Earth tail of the magnetosphere. A cold-dense plasma sheet (CDPS) is known to form during intervals of northward interplanetary magnetic field (IMF), and to be of solar wind origin primarily. The hot-tenuous plasma sheet is generally observed for non-northward IMF conditions and can often contain a large contribution from heavier ions (O+ primarily). Both types of populations are a source for the ring current during magnetically active times. Recent observations have also shown the transport of dense plasma from the dawn side of the plasma sheet boundary layer (PSBL) but the properties of this plasma and the potential influence it might have on the formation of the ring current has not been investigated in any detail. This project addresses the topic of plasma sheet properties and transport toward the inner magnetosphere and ring current region of the plasma sheet and PSBL particles in order to assess in a systematic fashion the role of plasma sheet density, temperature and local time asymmetries on the strength of magnetic storms. It aims to answer the following scientific questions: (a) How and where does the plasma sheet and boundary layer plasma enter the inner magnetosphere/ring current region? (b) What are the effects of plasma sheet properties (density, temperature, and local time asymmetries) on proton ring current strength and peak location? The research project will address these questions through a combination of data from key magnetospheric and solar wind science missions (Cluster, Los Alamos geosynchronous instruments, ACE) and simulation results using a kinetic model of the ring current. The research will also contribute to an educational goal. An undergraduate student research program is operated at Los Alamos and it is expected that one or more students will become involved in this project.