Global 3D MHD Modeling of the Solar Corona and Solar Wind

Arcadi V. Usmanov, Institute of Physics, University of St.-Petersburg, St.-Petersburg 198904, Russia

A self-consistent 3D MHD model of a steady coronal outflow with a flux of WKB Alfvén waves in a dipolar magnetic field is developed. The results of simulation demonstrate the formation of a bimodal structure consisting of fast and slow wind. The computed parameters are generally consistent with the data from the Ulysses mission and with parameters typically found at the coronal base. It is shown that two processes determine the meridional distribution of solar wind plasma and magnetic field parameters: (i) the primary meridional relaxation and formation of a flat meridional profile of all the flow and magnetic field parameters (outside the equatorial band) in the region where magnetic forces dominate the thermal and wave gradient forces, and (ii) the secondary meridional redistribution due to the poleward thermal pressure gradient that formed as a result of the primary process. A series of successful simulation runs for the three-dimensional solar wind flow in the axial and tilted dipole magnetic field geometry has been carried out. The results of the 3D simulation are consistent with and further extend those obtained previously with an axisymmetric model.