The Magnetospheric Response to 8 Minute-Period Strong-Amplitude Upstream Pressure Variations.

This paper documents a series of brief, strong (Ap/p=1), dynamic pressure oscillations which occurred in the region upstream of the earth's bow shock during a period of radial interplanetary magnetic field (IMF). The analyzed set of oscillations, which may be either intrinsic solar wind or bow shock-related phenomena, recur approximately every 8-10 minutes and their magnetic field signatures occur nearly simultaneously over great distances transverse to the earth-sun line. The pressure oscillations appear to drive tailward-moving magnetopause surface wavelets. In turn, the surface wavelets can be identified as hydromagnetic waves with strong compressional components in the outer magnetosphere and as quasi-periodic variations in electron precipitation and elliptically-polarized waves at high-latitude ground stations. We use observations by spacecraft in the outer dayside magnetosphere to predict geosynchronous and subsolar magnetic field strengths, the location of the subsolar magnetopause, the solar wind dynamic pressure, and variations in the energetic magnetospheric ion flux.