Abstract Details


Name: Soumyadeep Chatterjee
Affiliation: IIT Kanpur
Conference ID: TVS202510187
Title: Probing magnetic field inside the Sun from three decades of observed surface magnetograms
Authors and Co-Authors: Gopal Hazra
Abstract Type: Contributory Presentation
Abstract: Space weather and heliospheric disturbances are direct manifestations of the solar magnetic field, which is generated by the Sun’s interior dynamo. Constraining the interior magnetic field and its oscillatory behaviour remains one of the major challenges in solar physics. Observational techniques, including helioseismology, are unable to provide reliable estimates of the interior magnetic field. We reconstructed, for the first time, the dynamics of the large-scale interior magnetic field by assimilating observed line-of-sight photospheric magnetograms from MDI/SOHO and HMI/SDO, together with helioseismic differential rotation data, into a 3D dynamo model spanning three decades (1996–2025). Our data-driven model successfully reproduces key observational features, including the surface butterfly diagram, polar field evolution, and axial dipole moment. The reconstructed interior field near the base of the convection zone, dominated by its toroidal component, exhibits equatorward migration and reproduces the realistic amplitude and modulation of solar cycles 23–25. We further quantify the contribution of the non-axisymmetric component of the toroidal magnetic field, which becomes progressively less prominent with depth toward the tachocline. A strong correlation between our simulated toroidal field and sunspot number/area underscores the potential of our 3D magnetogram-driven model as a robust predictive tool for the solar cycle. We demonstrate that the assimilated dynamo model can forecast the peak amplitude and timing of solar cycles up to three years before solar maxima.