Nonradial and nonpolytropic astrophysical outflows

VII. Fitting ULYSSES solar wind data during minimum

¹ Observatoire de Paris, LUTH, 92190 Meudon Cedex, France e-mail: christophe.sauty@obspm.fr
² Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal
³ Departamento de Matemática Aplicada da Faculdade de Ciências, Universidade Porto, Rua do Campo Alegre, 657, 4150-007 Porto, Portugal
⁴ Observatoire de Paris, LESIA, 92190 Meudon Cedex, France
⁵ IASA and Section of Astrophysics, Astronomy & Mechanics, Department of Physics, University of Athens, Panepistimiopolis 157 84, Zografos, Greece

Received: 7 July 2004
Accepted: 20 October 2004

Abstract

Exact axisymmetric analytical solutions of the governing MHD equations for magnetized and rotating outflows are applied to the solar wind during solar minimum as observed by ULYSSES. Using the spacecraft data, the latitudinal dependences of physical quantities such as the density, velocity, magnetic field and temperature are analytically described. The self-similar solutions are then compared to the global structure of the wind from one solar radius to 5 AU and beyond, including consistently the rotation of the outflow. The model makes it possible to describe the initial flaring of the magnetic dipolar structure, reproducing in a satisfactory way the observed profiles of the velocity, density and temperature with heliocentric distance. Finally, this model is in agreement with the conjecture that the solar wind should not be collimated at large distances, even close to its rotational axis.