Summary
This work investigates interactions and mappings of the boundary layers, polar cusp and outer magnetosphere with the high latitude ionosphere. Primary diagnostic tools are plasma waves observed on the ground as geomagnetic pulsations. Established theory and observation allows for electromagnetic ion-cyclotron waves (ICWs) in the Pc1-2 (0.1-0.5 Hz) range observed by spacecraft in the equatorial magnetosphere to propagate in a field guided mode to the ionosphere, convert some energy to isotropic fast mode waves which duct parallel to the ground in a waveguide centred on the F2 region. Several decades of ground Pc1-2 pulsation observations are reviewed here and have attempted to classify, determine ICW wave sources and use Pc1-2 to identify magnetospheric regions mapped onto the ionosphere.