Application of a numerical path-preserving Roe scheme in background solar wind simulation

Abstract

The solar wind underpins the propagation of interplanetary disturbances and is central to space weather forecasting, with magnetohydrodynamic (MHD) simulations providing a key tool for studying its large-scale structures. This work applies the Numerical Path-Preserving Roe (NPP-Roe) scheme to background solar wind modeling to mitigate nonphysical intermediate shocks and spurious convergence associated with the conventional Roe scheme in ideal MHD Riemann problems, which stem from the misrepresentation of Alfvén waves. By correcting Alfvén-related eigenvalues, eigenvectors, wave strengths, and magnetic field orientations, the method preserves the physical property of Alfvén waves, maintaining tangential magnetic field magnitude while allowing directional changes. The scheme’s robustness is first validated using one-dimensional MHD Riemann problem. Three-dimensional simulations of the background solar wind during Carrington Rotation 2203 (CR 2203) are then performed by solving the ideal GLM-MHD equations via a finite volume approach combined with constrained least-squares reconstruction. The results indicate that the NPP-Roe scheme is able to capture the main large-scale coronal and solar wind features, including the radial velocity distribution, plasma density structure, and magnetic-field topology, with overall consistency with observational data. These results suggest that the NPP-Roe scheme is a viable option for global coronal solar wind MHD simulations and may provide a useful numerical framework for representing magnetic structures and discontinuities.