Theory and measurements of the cusp/magnetopause current layer
Keith, Wayne Russell
Winningham, J. David
Doctor of Philosophy
This thesis employs low-altitude satellite data taken in the northern and southern dayside magnetospheric cusps in order to determine if the magnetopause current layer has a continuous and identifiable footprint at low altitudes. The magnetopause current layer, at the outermost edge of the magnetosphere, is the site of interconnection between the Earth's geomagnetic field and the Interplanetary Magnetic Field of the magnetosheath. It is an active region in which the normal MHD assumptions cannot hold. Data from eight near-polar orbiting spacecraft are compared with predictions of a small wedge-shaped cusp at the dayside boundary of the polar cap. Precipitating particle data as well as high-energy particles, fields, and wave data are shown which are consistent with predicted features. A kinetic raytracing model and statistical survey of Astrid-2 and DMSP satellite data were also undertaken as part of this work and show this feature to be persistent and dependent on the IMF angle at the magnetopause, as expected. The study of this feature may lend new insight into the dynamics of the cusp and magnetospheric particle entry.
Astronomy; Astrophysics; Plasma physics