Modification of interplanetary shocks near the bow shock and through the magnetosheath

Abstract

Fast forward interplanetary (IP) shocks have been identified as a source of the largest geomagnetic disturbances. These shocks can evolve in the solar wind, and they are modified both by interaction with the bow shock and during their propagation through the magnetosheath. Our contribution continues the study of the evolution of IP shocks in the magnetosheath. We compare profiles of the magnetic field and plasma parameters observed in the magnetosheath with profiles of the same parameters predicted by an MHD magnetosheath numerical model. The IP shock transmission into and its propagation through the magnetosheath cause inward and then outward motions of the bow shock, and these motions result in an "indentation" of the bow shock surface. This indentation (trough) flows along the bow shock together with the IP shock. Furthermore, we found that the interaction of the IP shock with the bow shock results in two discontinuities. These effects are consistent with the simulations of the MHD magnetosheath model. Copyright 2007 by the American Geophysical Union.