Three-dimensional MHD modeling of the solar corona and solar wind: comparison with the Wang-Sheeley model
Arcadi V. Usmanov, Melvyn L. Goldstein, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA
We present simulation results from a tilted-dipole steady-state MHD model of the solar corona and solar wind and compare the output from the model with the Wang-Sheeley inverse relation between the divergence rate of magnetic flux tubes near the Sun (inferred from solar magnetograms) and the solar wind speed observed near Earth and at Ulysses. The boundary conditions are specified at the coronal base and the simulation region extends out to 10 AU. It is assumed that a flux of Alfvén waves with amplitude of 35 km/s emanates from the Sun and provides additional heating and acceleration for the coronal outflow in the open field regions. The waves are treated in the WKB approximation. The incorporation of wave acceleration allows us to reproduce the fast wind measurements obtained by Ulysses, while preserving reasonable agreement with plasma densities typically found at the coronal base. We show that the simulation results are in agreement with the empirical model of Wang and Sheeley.