The Distention of the Magnetosphere on May 11,1999: High Latitude Antartic Observations and Comparisons with Low Latitude Magnetic and Geopotential Data.

In this letter, we examine the Earth's ionospheric response on May 11,1999, to an unusually tenuous solar wind, focusing on magnetometer, riometer, and optical data from high geomagnetic latitudes in Antarctica. These observations complement northern hemisphere studies, and provide a global context in which to study this event. Comparisons are made with data taken from the HYDRA and PIXIE instruments onboard the POLAR satellite during a brief perigee pass over Antarctica on May 11, and with geomegnetic data collected from the polar cap to low latitudes.