Collaborative Research: CEDAR: Causal Relationships of Ion-neutral Coupling Processes at Mid-latitudes

本研究的目的是促进我们对高纬度热层强迫和中纬度等离子体密度结构在平静期和风暴期之间的耦合和因果关系的理解。该研究还将描述磁层和电离层之间高纬度边界的时空变化在产生中纬度观测到的变率方面的相对重要性。所获得的知识将通过确定模型中任何缺失的物理以及捕获相关过程所需的空间/时间分辨率来影响未来模型的发展。改进建模对于实现空间天气预报能力至关重要，并将加强研究和教育的基础设施。该项目将解决两个基本问题：1)高纬度对中性风的强迫作用与中纬度地区，特别是地磁风暴条件下电子密度的响应之间的因果关系是什么？2)高纬度驱动因素的时空变异与中纬度中性风和电离层结构的时空变异有何关系？由Fabry-Perot干涉仪（FPI）的北美热层-电离层观测网（NATION）进行的中纬度热层风和温度观测将与电离层数据同化四维（IDA4D）同化模式的随时间变化的三维电子密度估计相结合。在热层中性风和电子密度中观测到的动力学来源将通过应用反演算法（从电离层逆向工程估计模型参数；EMPIRE）来研究，该算法是根据电离层电子密度的三维时间演化分布来估计电离层驱动因素的。第一性原理全球电离层热层模型（GITM）也将用于阐明导致这种耦合的基本物理。本研究将有助于伊利诺伊大学和密歇根大学研究生的教育和培训。

The goal of this study is to advance our understanding of the coupling and causal links between high-latitude forcing of the thermosphere and mid-latitude plasma density structuring during both quiet and storm times. The study will also characterize the relative importance of spatial/temporal variation at the high-latitude boundary between the magnetosphere and ionosphere in generating observed variability in the mid-latitudes. The knowledge gained will impact the development of future models by identifying any missing physics in the models as well as the spatial/temporal resolutions required to capture relevant processes. Improving modeling is critical to enabling space weather forecasting capabilities, and will enhance the infrastructure for research and education. This project will address two fundamental questions: 1) What is the cause/effect relationship between high-latitude forcing on the neutral winds and the response of electron densities at mid-latitudes, especially during geomagnetic storm conditions? 2) What is the relationship between spatial/temporal variability within the high-latitude drivers and the variability observed within the mid-latitude neutral winds and ionospheric structure? Observations of mid-latitude thermospheric winds and temperatures made by the North American Thermosphere-Ionosphere Observation Network (NATION) of Fabry-Perot interferometers (FPI) will be coupled with time-dependent 3D electron density estimates from the Ionospheric Data Assimilation Four Dimensional (IDA4D) assimilative model. The source of the dynamics observed in the thermospheric neutral winds and electron density will be investigated through exercising an inversion algorithm (Estimating Model Parameters from Ionospheric Reverse Engineering; EMPIRE) developed to estimate the ionospheric drivers from three-dimensional, time-evolving distributions of ionospheric electron densities. The first-principles Global Ionosphere Thermosphere Model (GITM) will also be used to elucidate the underlying physics responsible for the coupling. This study will contribute to the education and training of graduate students at the University of Illinois and the University of Michigan.