Magnetosphere-ionosphere coupling is the process connecting hot, low density plasma in the magnetosphere with the cold, high density plasma in the ionosphere. This coupling is especially important during geomagnetic storms and substorms when increasing currents in the magnetosphere close through the ionosphere, resulting in increased outflow of ionospheric plasma into the magnetosphere and increased precipitation of energized magnetospheric plasma into the ionosphere. This process, important to understanding space weather impacts, will be studied with a combination of space-based observations and ground-based auroral imagers and the NSF-supported Poker Flat meridian spectrograph. The project supports research of a graduate student from a member of an underrepresented group in STEM and three women in early career stages.<br/><br/>Coupling between the Earth’s ionosphere and magnetosphere is a critical component of the dynamics that occur during storms and substorms. To improve understanding of the connections between phenomena in the magnetotail and in the ionosphere, the research will combine global imaging of the magnetosphere using energetic neutral atoms with auroral imaging of the ionosphere. These techniques will be supported by in situ measurements and global modeling. Case studies of particular active intervals will be used as well as statistical studies that include superposed epoch analyses. The following science questions will be addressed: (1) Under what conditions do we observe both energized ions in the magnetotail and auroral enhancements? (2) What is the temporal relationship between ion energization in the magnetotail and auroral enhancements? (3) What is the spatial relationship between mesoscale regions of energized ions in the magnetotail and auroral enhancements?<br/><br/>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.