Collaborative Research: GEM--Impact of Solar Wind Dynamic Pressure Enhancement on the Cusp and Polar Cap Ion Source

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Outflow ions from the ionosphere are one of the major particle sources for the Earth's space environment. Their dynamics in the region inside the geosynchronous orbits play a crucial role in space weather disturbances, whose effects include satellite drag, disruption in communication and navigation systems, and damaging electric power grids. This project is focused on understanding the physical processes of how one of the drivers from the Sun, solar wind compression of the geospace, generates these outflow ions and their transport. The compression can often be strong and impulsive, but we currently have little knowledge in both observations and simulations on the resulting outflow ions. This project will establish such knowledge, which is urgently needed in the space community to improve our forecast ability for impulsive space weather events. This project supports the education of a graduate student by providing balanced tasks for developing the student's essential research ability in both simulations and data analysis.The science goal of this project is to understand how solar wind compression impacts outflow ions. The two main objectives and methods are (1) Investigating Cluster satellite data to establish a better observational understanding of temporal variations of the ion fluxes in the cusp and lobes resulting from the compression. (2) Conduct 3D global hybrid simulations to evaluate the physical processes behind the outflow ions caused by the compression. The hybrid simulation is currently the most appropriate tool to take into account the kinetic processes of these outflow ions. The simulations are designed to be compared with the observation results to establish a solid physical understanding. It will also improve our current model specification of the outflow ions that can eventually be incorporated into space weather modeling to achieve a better forecast of the impact of solar wind compression.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.