CEDAR: Analysis of CEDAR-HLPS Polar Cap Arc Observations Using Model Observation Comparison Techniques

雪松高纬度等离子体结构（HLPS）计划已经开展了几次观测活动，以获得有关太阳排列的极帽弧（SA）的综合数据库。在USU，两种不同的建模工作已经产生了与极帽太阳对准弧有关的模型，即一个升级的时间依赖电离层模型，其中嵌入了太阳对准的极帽弧（tdm -SA）和一个MHD耦合磁层-电离层极帽太阳对准弧模型（M-I SA）。pi建议在五个特定的合作调查中使用这两个模型，利用这些CEDAR-HLPS数据，每个调查都有一个特定的科学目标。第一和第二项研究涉及理解与SA相关的黎明-黄昏（反之亦然）漂移及其多弧、条纹性质。这两项研究都使用了M-I SA模型，该模型显示了这两种特征。三是利用HLPS对多个电动力学和等离子体参数的观测，对TDIM-SA模型进行验证，特别是对交叉弧漂移速度为关键参数的模型预测。我们的第四个研究是了解在极帽和极光弧变化期间在极帽和极光弧附近观测到的强对流旋转。同样，这种类型的特征也存在于M-I SA模拟中。在sa附近观察到强烈的血浆耗尽，并初步与电动力电流闭合要求有关。在第五项研究中，我们将使用TDIM-SA来量化所有电动力学参数，并评估该假设是否是血浆消耗的来源。

The CEDAR High Latitude Plasma Structures (HLPS) initiative has carried out several observational campaigns to acquire comprehensive data bases on Sun-aligned polar cap arcs (SA). At USU, two distinct modeling efforts have produced models that pertain to polar cap Sun-aligned arcs, namely, an upgraded Time Dependent Ionospheric Model with embedded Sun-aligned polar cap arcs (TDIM-SA) and an MHD coupled magnetosphere-ionosphere polar cap Sun-aligned arc model (M-I SA). The PIs propose to use these two models in five specific collaborative investigations utilizing these CEDAR-HLPS data lets, each investigation having a specific scientific goal. The first and second investigations pertain to understanding the dawn-dusk (or vice versa) drift associated with SA and their multiple arc, striated, nature. Both of these studies use the M-I SA model which exhibits both of these features. The third is to use the HLPS observations of many electrodynamic and plasma parameters to validate the TDIM-SA model, especially the model prediction that the cross arc drift speed is a key parameter. Our fourth study is to understand the strong convection rotation observed in the vicinity of polar cap and auroral arcs during times when the arc is changing. Again, this type of feature is present in the M-I SA simulations. Strong plasma depletions have been observed adjacent to SAs and have been tentatively associated with electrodynamic current closure requirements. For this fifth study, we will use the TDIM-SA to quantify all the electrodynamic parameters and evaluate if this hypothesis is the source of the plasma depletions.