Ground magnetic response to sudden changes in the interplanetary magnetic field orientation

Recent observations have shown that a discontinuity in the interplanetary magnetic field (IMF) can produce a discernible ground magnetic signature at crisp latitudes, whose characteristics closely resemble those of ionospheric traveling convection vortices. It has been suggested that a hot flow anomaly (HFA), produced by the interaction of certain tangential discontinuities with the bow shock, is the mechanism through which an IMF discontinuity can produce a ground magnetic response. Using solar wind plasma and IMF data from the IMP 8 satellite from 1992-1995, we have identified and categorized intervals during which IMF discontinuities are observed. Ground magnetometer observations from the Greenland coastal chains and the MAGIC array have been used to characterize any resulting ground response. The occurrence of ground signatures appears to be weakly related to the conditions necessary to produce HFAs.