Three-dimensional, three-fluid MHD modeling of the solar wind with turbulence transport and heating

A. V. Usmanov 1,2, M. L. Goldstein 2, and W. H. Matthaeus 1

1 Department of Physics and Astronomy and Bartol Research Institute, University of Delaware, Newark, DE 19716

2 Code 673, NASA Goddard Space Flight Center, Greenbelt, MD 2077

We have developed a fully three-dimensional magnetohydrodynamic solar wind model that incorporates transport of turbulence and treats solar wind protons, electrons, and interstellar pickup protons as separate fluids. Numerical solutions of mean-field Reynolds-averaged solar wind equations coupled with turbulence transport equations are constructed by a time relaxation method in the region from 0.3 to 100 AU (but still inside the termination shock). The model equations include the effects of electron heat conduction, Coulomb collisions, photoionization of interstellar hydrogen atoms and their charge exchange with solar wind protons, turbulence energy generation by pickup protons, and turbulent heating of solar wind protons and electrons. The turbulence transport model is based on Reynolds decomposition and averaging and uses turbulence phenomenologies to describe the conversion of fluctuation energy into heat via a turbulent cascade. We compute the global structure of the solar wind plasma, magnetic field, and turbulence throughout the heliosphere and compare the results with Ulysses and Voyager 2 observations.