Semi-empirical MHD model of the solar wind and its comparison with Ulysses

We have developed a 2D semi-empirical model (Sittler and Guhathakurta 1999) of the corona and the interplanetary medium using the time independent MHD equations and assuming azimuthal symmetry, utilizing the SOHO, Spartan and Ulysses observations. The model uses as inputs (1) an empirically derived global electron density distribution using LASCO, Mark III and Spartan whit e light observations and in situ observations of the Ulysses spacecraft, an d (2) an empirical model of the coronal magnetic field topology using SOHO/ LASCO and EIT observations. The model requires an estimate of solar wind ve locity as a function of latitude at 1 AU and the radial component of the ma gnetic field at 1 AU, for which we use Ulysses plasma and magnetic field da ta results respectively. The model makes estimates as a function of radial distance and latitude of various fluid parameters of the plasma such as flo w velocity V, temperature T-eff, and heat flux Q(eff) which are derived fro m the equations of conservation of mass, momentum and energy, respectively, in the rotating frame of the Sun. The term "effective" indicates possible wave contributions. The model can be used as a planning tool for such missi ons as Solar Probe and provide an empirical framework for theoretical model s of the salar corona and salar wind.