The Effects of Magnetopause Motion and Substorm Stretching and Dipolarization on Magnetic Fields in the Inner Magnetosphere

Increases in the solar wind dynamic pressure compress the magnetosphere, enhance magnetic field strengths and push the magnetopause inward. Enhanced reconnection on the magnetopause, as might be expected during southward IMF conditions, launches rarefaction waves into the magnetosphere, decreases magnetic field strengths, and erodes the magnetopause inward. Nightside magnetotail magnetic fields stretch tailward during erosion events and ultimately snap back to dipolar orientations at substorm onset. The effects can be seen clearly in geosynchronous orbit. We present a statistical survey of the effects of magnetopause motion and substorm stretching and dipolarization on magnetic fields deep inside both the dayside and nightside magnetosphere using observations from NOAA’s GOES satellites.