CEDAR: Dynamics of SAPS (SubAuroral Polarization Streams) during Geomagnetic Disturbances and Their Effects on the Coupled Ionosphere-Thermosphere System

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This project aims to comprehensively investigate the dynamics of SubAuroral Polarization Streams (SAPS) during geomagnetic disturbances and their effects on the ionosphere and thermosphere (IT). The dynamics of SAPS is an outstanding magnetosphere-ionosphere coupling problem associated with the electrodynamics at the interface between the hot and cold particle populations in the inner magnetosphere. The generation mechanisms of SAPS during geomagnetic active times, in particular substorms, are still not well understood, nor are the wave-like oscillations embedded within SAPS, or the effects of SAPS on the global IT system. Ground-based observations (Super Dual Auroral Radar Network (SuperDARN), Poker Flat Incoherent Scatter Radar (PFISR) and all-sky imager arrays) and space-based measurements (Time History of Events and Macroscale Interactions during Substorms (THEMIS) and the Van Allen probes), as well as the Global Ionosphere Thermosphere Model (GITM), will be used to carry out an integrated study of the dynamics of SAPS and their effects on the coupled IT system. Specific objectives are (1) to statistically construct the distribution of response times of SAPS intensifications relative to substorm onset and the distribution of intensification durations, and investigate the underlying mechanisms responsible for the SAPS intensification and for variable time delays, (2) to characterize the wave activity within the SAPS and their magnetospheric counterparts and identify the nature of the wave activity, and (3) to quantitatively evaluate the role of ion precipitation in affecting the SAPS evolution and the effect of the SAPS intensification after substorm onset and the wavy-structures of SAPS on the IT system using GITM. This project will support the professional development of two young researchers, including one female. It will also involve participation of a graduate student and summer REU students. Project results will be disseminated broadly. The project is interdisciplinary and will be valuable to the GEM (Geospace Environment Modeling) community, and contribute to an improved understanding of space-weather events.