CEDAR: Sunlit Investigations of Soft Arcs and the Cusp Boundary with Coordinated ISR and HiRISE Diagnostics

Sri International, Menlo Park CA

Investigators

Abstract

The investigators will study magnetosheath-ionosphere interaction by probing electron density, electron temperature and oxygen emission structures in the dayside high-latitude ionosphere. Long-term, ground-based studies of the cusp boundary and dayside auroral arcs can greatly advance our understanding of magnetic merging by measuring the morphological response of the cusp to solar wind forcing, and by examining the relationship of the cusp boundary to the location and motion of soft arcs. This study will also provide an opportunity to study the energetics of dayside auroral arcs. By merging measurements of plasma density and 630 nm emissions with a solar ultraviolet photochemical model, the investigators will extend studies of daylit aurora to a low energy regime heretofore undetectable with conventional radar and optical tools. This study will help to understand how the morphology of the cusp responds to solar forcing, the relationship between daylit arcs and the cusp boundary, and the way in which the motion of dayside arcs is controlled by the interplanetary magnetic field. The observations will be made with a spectrograph and an incoherent scatter radar located at Sondrestrom, Greenland. A web-based real-time archive of daytime auroral measurements, linked to the existing repository of nightside images from the Sondrestrom all-sky imager, will be provided as a resource for future collaborators. This web archive will also contain a descriptive narrative and links to satellite images aimed at the general public, so as to increase awareness of auroral light emission as a round-the-clock phenomena.