MHD SIMULATION STUDY OF THE EFFECTS OF TRANSITIONS IN THE SOLAR WIND AND IMF ON THE MAGNETOSPHERE

Dr. Steve Slinker
Naval Research Laboratory

We use a global, 3D, MHD simulation model to study the response of the Earth's magnetosphere and ionosphere to transitions in the solar wind. Two types of transitions are considered: a sudden change in the dynamic pressure and a sudden change in the IMF orientation. We consider numerical experiments under idealized conditions which show that observations can be explained in terms of hydromagnetic waves. A sudden pressure pulse produces pairs of traveling vortices in the ionospheric convection flow which we relate to corresponding flows in the magnetosphere. Convection response to an IMF rotation propagates throughout the polar ionosphere within a few minutes. We also compare the simulation results to observations for real event studies, where the model is driven by the measured solar wind.