Magnetospheric response to a hot flow anomaly

On July 24, 1996, Interball-1 was nominally located outside the dayside bow shock. For a few moments, the magnetopause moved outward to engulf the spacecraft. Wind observations provide no evidence for any corresponding perturbation in solar wind plasma parameters, although they do provide evidence for the passage of a tangential discontinuity. The bulge in the magnetopause subsequently moved past Ceotail, which was nominally located in the magnetosheath downstream from Interball-1. High-latitude dayside ground magnetograms recorded an impulsive event at this time. We interpret the observations in terms of the formation of a hot flow anomaly at the bow shock and its subsequent interaction with the magnetosphere.