The purpose of this project is to study the formation and evolution of large scale plasma structures in the high latitude ionosphere. The plasma structures to be studied are 100 to 1000 km scale enhancements of the F region plasma density. The program combines observations with numerical modeling. The observational program consists of coordinated measurements using the Sondrestrom and EISCAT radars, as well as other ground-based instruments. The modeling effort involves simulations guided by both specific observations and various theoretical scenarios. In support of this effort, an existing high-latitude F-region model will be improved as needed to include multi-species, E-region chemistry, and calculations of the ion and electron temperatures. The primary goal of this effort is to understand the mechanisms that control the appearance, size, and shape of the plasma patches in the polar cap and the ionization enhancements in the auroral oval. The results will provide valuable insights into the physics of magnetosphere-ionosphere coupling.
