Schematic diagram showing the subdomains and mathematical models used in each region in the proposed Sun-to-Earth data-driven solar wind model. The PFSS model is used to describe the coronal magnetic field from the Sun’s surface up to a spherical surface where magnetic field lines are forced to open. From this surface, which is usually placed at ≈2.5 R₀, the SCS model describes the coronal field up to 20–30 R₀, where the inner MHD boundary conditions are applied. A global MHD model is then used to describe the solar wind plasma and its propagation through interplanetary space in the inner heliosphere.