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

在磁层的近地尾部可以观察到冷致密等离子体和热稀薄等离子体。冷致密等离子体层（CDPS）是在向北行星际磁场（IMF）的间隔期间形成的，它主要是太阳风的起源。热纤细等离子体层通常在非北向的IMF条件下观察到，并且通常可以包含来自较重离子（主要是O+）的大量贡献。在磁活动时期，这两种类型的人口都是环电流的来源。最近的观测也显示了密集等离子体从等离子体片边界层（PSBL）的黎明面传输，但这种等离子体的性质及其可能对环电流形成的潜在影响尚未得到详细研究。本项目探讨了等离子体片的性质和向内磁层的传输以及等离子体片和PSBL粒子的环电流区域，以系统的方式评估等离子体片密度、温度和局部时间不对称性对磁暴强度的作用。它旨在回答以下科学问题：(a)等离子体片和边界层等离子体如何以及在何处进入内磁层/环电流区？(b)等离子体片特性（密度、温度和局部时间不对称性）对质子环电流强度和峰值位置的影响是什么？该研究项目将通过结合来自关键磁层和太阳风科学任务（群集，洛斯阿拉莫斯地球同步仪器，ACE）的数据和使用环电流动力学模型的模拟结果来解决这些问题。这项研究也将有助于实现教育目标。洛斯阿拉莫斯有一个本科生研究项目，预计会有一名或多名学生参与这个项目。

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.