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

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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.