Magnetopause flow vortices revealed during high speed solar wind streams

Using MHD simulation and Cluster and Geotail data for high speed solar wind flow intervals in 2002, we illustrate the 3D nature of magnetopause flow vortices, and possible consequences for Earth's magnetosphere. We use observations from ACE and Wind to show characteristics of the high speed streams, including intrinsic power. Geotail and Cluster are near the magnetopause along the flanks and over the poles, respectively. GOES and LANL data are used to show the magnetospheric response. Preliminary results show that vortices on the flanks preferentially have their axes in the z-direction and are both clockwise and counterclockwise. Twisting of the magnetic field inside the vortices is crucial to finding pockets of reconnection with associated transport of particles into the magnetosphere. Eddy transport of particles can also result in turbulent regions. Energy can also be transferred across the magnetopause. Geotail observations near the magnetopause show enhanced compressional power at Pc5 frequencies, especially at the nose and on the dawn flank, both in the magnetosheath and the adjacent boundary layer. GOES 8 observations of dawn pulsations follow the trend of the compressional magnetic field fluctuations, that is higher at first and then reduced. Compressional magnetic field fluctuations may control the level of Pc5 pulsations on the dawn side. Northward IMF and high speed solar wind along with Geotail observations of magnetopause motion and MHD simulations of vortices along the flanks suggest that a Kelvin-Helmholtz (K-H) instability may contribute to transport of the compressional energy into the magnetosphere.