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Framework for Understanding Global Versus Local Energy Deposition into the Ionosphere and Thermosphere

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Final rept. 15 May 2012-15 May 2015

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The primary objective of this investigation was aimed at understanding how regional and localized heating of the ionosphere and thermosphere can occur and how it affects the structure of the thermosphere, in particular with respect to neutral upwelling and satellite drag. This study both employed data analysis, primarily using DMSP data, and global modeling using the coupled OpenGGCM-CTIM model. We studied the thermospheric response to sheath-enhanced storms and found that an event chain of high solar wind density, soft electron precipitation, and NO cooling may lead to thermosphere contraction and density mispredictions. Using OpenGGCM modeling we found that the soft electron precipitation can profoundly alter the current closure in the ionosphere and change the Joule heating patterns. We re-processed ST-5 and DMSP magnetic field data to show that magnetic perturbations track the passage of co-rotating interaction regions and high-speed solar wind, and that a radial IMF component can enhance a weak southward IMF to lead to sawtooth oscillations. We examined the thermospheric neutral density response to 172 solar wind high-speed streams HSSs and the associated stream interfaces during the equinox seasons of 2002-2008 to show that HSSs produce prolonged enhancements in satellite drag. We found that distinct signatures exist in neutral density response that can be anticipated days in advance based on currently available knowledge of on-disk coronal holes. f on-disk coronal holes. We co-developed capabilities for operational multi-day geomagnetic Disturbance storm time Dst i.e., a data-driven, deterministic algorithm called Anemomilos for large, medium, and small storms, depending upon transit time to the Earth. Using global modeling we showed that steep increases in dynamic pressure cause different effects depending on whether the IMF is northward or southward.

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  • Atmospheric Physics
  • Unmanned Spacecraft

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