The Differences in Onset Times of Hemispherically Conjugate Auroral Stations

这是一个被归类为“高风险-高回报”的项目，为期一年的试点研究。该项目将研究在北极光和南极光区域同时观测到的个别亚暴和其他极光事件的开始时间的半球差异。在地球空间遥远的地方，磁亚暴(它们被称为亚暴)重塑了地球的磁尾。这一过程爆炸性地释放能量，使受影响场线脚下电离层中更接近地球的电流和高能电荷粒子沉淀立即加强，并加剧了极光发射。调查将利用最近完成的磁力计测站配对，这些测站位于磁力线向地球两端的两端，这些磁力线贯穿地球磁尾，亚暴就是在那里启动的。在每个半球爆发之前的时间和极光特征序列的差异将提供关于引起这些极端动态事件的潜在物理过程的有争议的和仍然激烈争论的理论的新信息，并对其施加额外的限制。在这个项目中(以前从未尝试过)，由于需要将磁层中的亚风暴过程本身造成的时间差异与其他时间偏移源分开，例如由于亚风暴开始特征信号进入磁力计视场的传播路径中的细微半球间差异，这带来了重大的关闭风险。能否利用极光图像或其他信息消除这些额外的时差来源，以及提取与亚风暴有关的真正时差，是这项初步研究的主要重点。这项技术的高额回报，如果被证明是可行的，是对一个长期存在的地球空间难题的新视角，这个难题继续阻碍着理解地球附近恶劣空间天气的进展。进展很重要，因为在近地空间危险的辐射环境中，宇航员将人类企业送入太空，卫星是重要的社会基础设施轨道的关键。与这些爆炸事件相关的磁场的剧烈突然变化在固体地球上引发电流，威胁到电网运行的长期损害和短期(潜在危险)中断。这项试点研究将为本科生和研究生提供教育经验，为未来科学劳动力的发展做出贡献。该项目是一项统计研究，目的是根据地面磁力计的亚暴起始点签名来衡量各个亚暴的起始点在两个半球之间的显着差异。有了这些信息，就有可能确定两个突出的亚风暴模型中哪一个与计时观测更一致。该项目的第二阶段将通过检查行星际磁场的方向、太阳风条件和亚暴开始期间的世界时间来确定差异的原因。一项规模较小的研究将与一对共轭全天成像仪观察到的起始点差异进行比较，如果有的话。

This is a one-year pilot study of a project classified as "high risk - high reward". The project will study hemispheric differences in the onset times of individual substorms and other auroral events observed simultaneously in the northern and southern auroral regions. Magnetic substorms (as they are called) reshape the Earth's magnetotail far out in Geospace. This process explosively releases energy powering an immediate intensification of currents and energetic charge particle precipitation closer to Earth in the ionosphere at the foot points of the affected field lines, and an intensification of auroral emissions. The investigation will take advantage of recently completed pairings of magnetometer stations located at the two Earthward ends of magnetic field lines that thread through the Earth's magnetotail where substorms are initiated. Differences in timing as well as the sequence of auroral features that precede the onset in each hemisphere will provide new information about, and place additional constraints on, controversial and still intensely debated theories about the underlying physical process(es) responsible for these extremely dynamic events. Significant closure risk is introduced in this project (which has never before been attempted) by the need to separate out the difference in timing due to the substorm process itself in the magnetosphere from other sources of timing offsets, for example, due to slight inter-hemispheric differences in the propagation path of a substorm onset signature into the magnetometer field of view. Whether these additional sources of timing differences can be removed using auroral images or other information, and the true substorm-related timing differences extracted, is the primary focus of this pilot study. The high reward of this technique, if proven feasible, is a new view into a long standing Geospace puzzle that continues to hinder progress in understanding severe space weather in the Earth's vicinity. Progress is important because in the hazardous radiation environment in near-Earth space, astronauts carry human enterprises into space and satellites that are key to important societal infrastructures orbit. The intense abrupt changes in the magnetic field associated with these explosive events induce currents in the solid Earth threatening long-term damage and shorter-term (potentially dangerous) disruptions in the operation of electric power grids. This pilot study will provide an educational experience to an undergraduate and a graduate student, contributing to the development of the future scientific workforce. The project is a statistical study that aims to identify significant difference between the hemispheres in the onset time for individual substorms as measured by signatures of the onset in ground-based magnetometers. Given this information, it may be possible to determine which of two prominent substorm models are more consistent with the timing observations. The second phase of the project will look to identify causes of the differences by examining the orientation of the interplanetary magnetic field, solar wind conditions, and the Universal Time during the substorm onset. A smaller study will compare onset differences with those observed in a pair of conjugate all-sky imagers, when available.