The Role of Farside Magnetic Structures in Modeling the 2024 Solar Eclipse

Abstract The corona is a crucial region that connects the solar surface to the solar wind and serves as the primary site of solar activity. The 2024 total solar eclipse (TSE) provides a unique opportunity to investigate the large-scale coronal structure. Combined with TSE observations, we study the impact of the magnetic structure of the farside active region, located in the eastern hemisphere of the Sun that has not yet rotated into the Earth field of view, on a global magnetohydrodynamic simulation. To address the limitation of single-view measurements for the routine synoptic map, we correct the magnetic field in the farside region by incorporating full-disk magnetograms measured several days after the TSE, allowing us to capture the temporal evolution of the photospheric magnetic field in near real time. Simulation results demonstrate that the local magnetic field in the farside active region can significantly influence the global coronal structure, by altering the position of the heliospheric current sheet, and further affect the global distribution of plasma parameters, even in polar regions. A comparison of the simulation results with white-light TSE + Large Angle and Spectrometric Coronagraph C2 observations and in situ measurements by the Parker Solar Probe reveals that the composite synoptic map improves the accuracy of the coronal modeling. This work provides robust support for advancing our understanding of coronal evolution, as well as deepening the link between the photosphere and large-scale coronal structure. Furthermore, it establishes a theoretical foundation for the future development of multiview stereoscopic measurements of the photospheric magnetic field.