Properties of Meso-scale Polar Cap Structures and their Coupling to Nightside Auroral Dynamics

太阳风与地球磁场的耦合对近地空间环境产生一系列干扰效应。 通信、导航以及能源生产和分配可能受到这种空间天气的严重影响。预测可能影响这些技术的扰动的能力取决于对日地相连系统的详细了解和理解，包括磁层和电离层之间复杂的耦合过程。后者的一个特别方面是在极冠观测到的极光发射的斑块和弧。最近的一些研究表明，这些结构，起源于阳面，可以漂移越过极冠，并在产生和动态的空间天气扰动在阴面电离层中发挥作用。 确定这些极冠结构的确切性质及其与夜侧电离层和磁层其他动态特征的关系是该项目的主要目标。 它将试图通过综合分析从各种来源同时观察到的有关现象。 由此产生的认识是朝着能够将这一影响纳入电离层空间气象规格和预测模型迈出的关键一步。 作为研究工作的一部分，将培训一名研究生。该项目的目的是确定极冠斑块和弧的特性及其与极光增强（PBIs）和流光的统计关联。Airglow 630.0 nm成像仪将用于跟踪极冠结构，并确定极冠斑块之前的PBI比例，以及导致PBI的极冠斑块比例。将通过雷达测量确定极冠斑块/弧的性质，如大小和速度，并通过共轭航天器确定相应的波瓣测量（流量、粒子、FAC结构）。 研究工作的具体项目目标包括：（1）建立气辉/电弧-PBI的统计联系，（2）确定极冠中尺度结构的性质，（3）建立电离层流动通道的可能磁层对应物。

The coupling of the solar wind with Earth's magnetic field gives rise to a range of disturbance effects in the space environment near Earth. Communications, navigation and energy production and distribution can be significantly affected by this space weather. The ability to forecast disturbances that may impact these technologies hinges upon detailed knowledge and understanding of the connected Sun-Earth system, including complicated coupling processes between the magnetosphere and ionosphere. A particular aspect of the latter is patches and arcs of auroral emissions observed in the polar cap. Some recent studies suggest that these structures, originating on the dayside, can drift across the polar cap and play a role in the creation and dynamics of space weather disturbances in the nightside ionosphere. Determining the precise nature of these polar cap structures and their relation to other dynamic features in the nightside ionosphere and magnetosphere is the main objective of this project. It will be attempted through a comprehensive analysis of simultaneous observations of the relevant phenomena from a variety of sources. The resulting understanding constitutes a critical step towards being able to include this effect in ionospheric space weather specification and forecast models. A graduate student will be trained as part of the research effort. This project aims to determine the properties of polar cap patches and arcs and their statistical association with auroral intensifications (PBIs) and streamers. Airglow 630.0 nm imagers will be used to track polar cap structures and determine the fraction of PBIs that are preceded by polar cap patches, and the fraction of polar cap patches that lead to PBIs. The properties of the polar cap patches/arcs such as size and speed will be determined with radar measurements, and the corresponding lobe measurements (flow, particle, FAC structure) determined with conjugate spacecraft. Specific project goals for the research effort include: (1) Establishing the airglow/arc-PBI connection statistically, (2) Determining the properties of the meso-scale structures in the polar cap, and (3) Establishing the possible magnetospheric counterpart for the ionospheric flow channels.