Structure of the Earth's magnetosphere under Northward IMF conditions

地球磁场在太阳风中形成一个空腔，称为磁层；太阳风和磁层之间的相互作用是近地空间动力学的最终原因，包括辐射带强度的变化和最壮观的极光（北极光和南极光）的展示。这些相互作用的性质取决于与太阳风相关的磁场方向（行星际磁场，简称IMF）；国际货币基金组织的“向南”方向（与地球磁场相反）对许多磁层过程是有利的，但国际货币基金组织的方向是高度可变的，相比之下，人们对国际货币基金组织向北条件下的磁层动力学知之甚少。其中一个例子是地球磁层的夜间结构，它形成了一个延伸的磁尾。磁尾由夹在两个被称为叶的低密度区域之间的等离子体片组成。在教科书中磁尾的图片中，低纬度的“等离子体片”是热的，而在叶状体中的等离子体是非常冷的，通常密度很低。然而，最近的一系列论文已经开始挑战这一范式，并发现在某些条件下，可以在叶中观察到异常热/高密度的等离子体，其中一些与令人困惑的“高纬度”极光发射有关，这些极光发射位于主要极光区域的极地。引起等离子体结构和高纬度极光发射的机制引起了激烈的争论。该项目的目的是使用来自航天器的原位卫星数据，如欧洲航天局的集群任务，以确定和解释与北IMF相关的更复杂间隔期间的磁尾结构。这将从北向国际货币基金组织条件下等离子体环境的统计分类开始，并将导致与全球尺度极光数据集的比较。我们期望这项工作将对我们理解磁层对北向IMF条件的反应作出重大贡献。

The Earth's magnetic field forms a cavity in the solar wind called the magnetosphere; the interaction between the solar wind and the magnetosphere is ultimately responsible for the dynamics of near-Earth space, including variations in the intensity of the radiation belts and the most spectacular displays of the aurora (the northern and southern lights). The nature of these interactions depends on the orientation of the magnetic field associated with the solar wind (the interplanetary magnetic field, or IMF); a "southward" orientation of the IMF (opposite to the Earth's magnetic field) is preferential for many magnetospheric processes, but the IMF direction is highly variable, and the dynamics of the magnetosphere under northward IMF conditions are, in comparison, poorly understood. One example of this is the structure of the night side of the Earth's magnetosphere, which forms an extended magnetotail. The magnetotail consists of a plasma sheet sandwiched between two low density regions called the lobes. In the textbook picture of the magnetotail, the low latitude "plasma sheet" is hot, whereas the plasma in the lobes is very cold and usually low in density. However, a recent series of papers have begun to challenge this paradigm, and have found that under certain conditions uncharacteristically hotter/higher density plasma can be observed in the lobes, some of which are associated with perplexing "high latitude" auroral emissions which lie poleward of the main auroral region. The mechanisms causing both the plasma structure and the high latitude auroral emissions are hotly debated. The aim of this project is to use in situ satellite data from spacecraft such as the European Space Agency's Cluster mission to determine and explain the structure of the magnetotail during the more complex intervals associated with northward IMF. This will begin with a statistical classification of the plasma environment during northward IMF conditions, and will lead on to a comparison with global scale auroral datasets. We expect this work will lead to a significant contribution to our understanding of the magnetosphere's response to northward IMF conditions.