An integral component of the multi-agency U.S. Global Change Research Program (Our Changing Planet," Committee on Earth Sciences, 1991) is understanding and modeling the geospace environment. As part of its contribution to the U.S. Global Change Research Program, the National Science Foundation's Division of Atmospheric Sciences has established a new research initiative, Geospace Environment Modeling (GEM), with the goal of supporting basic research into the dynamical and structural properties of geospace, leading to the construction of a global geospace model with predictive capability. The subjects of the first GEM campaign are the magnetospheric boundary, the magnetosheath beyond it, and the connection from the boundary through the magnetosphere to the ionosphere. Recent observation suggest that waves generated in the vicinity of the magnetopause and boundary layer regions may be transported into the polar cusp. THis grant involves the study of compressional wave propagation from a generation region near the magnetopause into the polar cusp and an examination of the instabilities associated with ion injected into the polar cusp from the magnetosheat. For both studies a primary consideration will be to compare the results with observed magnetic pulsation signatures.
