Transmission of Solar Wind Hydromagnetic Energy into the High Latitude Magnetosphere.

This article highlights some of our recent research on the contributions of upstream hydromagnetic waves to geomagnetic fluctuations observed in the Pc 3-4 frequency range near magnetospheric cusp latitudes. Results presented show the dependence of Pc 3 occurrence at South Pole on solar wind speed and interplanetary magnetic field magnitude and direction. Although some evidence clearly supports the idea of an upstream wave source for high latitude, dayside Pc 3 energy, we conclude that other source (s) must be more important to account for most of the observed activity in the Pc 3-4 band. Further research is needed to clarify the different controls between broad-banded and nearly monochromatic wave occurrences as well as to relate these high latitude conclusions to observations made deeper within the magnetosphere.