Helio-latitude Dependence of the Solar Wind Parameters and the Magneto-Gravitational Dragging of the Solar Wind

Abstract

A theoretical model of the magnetic-field coupling to the background gravitational field of a rotating Sun-like star is used here to calculate the solar-wind parameters dependence on the helio-latitude. In the measurements of the solar-wind parameters in Ulysses’ first full polar orbit (McComas et al.: J. Geophys. Res. 105, 10419, 2000), the solar-wind parameters display a uniform behavior in the high-latitude regions compared with the slow variability in the low latitudes during solar minimum. Also the long-term variations in the solar-wind parameters reported in Ulysses’ second and third orbits (McComas et al.: Geophys. Res. Lett. 35, L18103, 2008) are interpreted in terms of the magnetic-field variations during the solar cycle. The solar-wind acceleration due to the magneto-gravitational field around the Sun is shown to lead to mass flux and speed distribution as functions of the helio-latitude that exhibit the observed distinction between the solar-wind parameters in low and high latitudes. The calculated proton density, solar-wind temperature variation, and the momentum-flux profiles over the solar surface are found to be consistent with Ulysses’ first full-polar-orbit data.