[M-GI35] Computational sciences on the universe, galaxies, stars, planets, and their environments

[MGI35-P01] Formation of super-strong magnetic field in a delta type sunspots pair in radiation magnetohydrodynamic simulations

*Hideyuki Hotta¹, Shin Toriumi² (1.Graduate School of Science, Chiba University, 2.Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency)

Keywords:Sun, Sunspot

We carry out high-resolution radiative magnetohydrodynamic (RMHD) simulations to investigate the formation mechanism of the super-strong magnetic field in delta-type sunspots. Sunspots have strong magnetic fields of 3000 G, usually at the center. When the positive and negative sunspots are approached, delta-type sunspots are occasionally formed, and recent observations revealed the existence of exceptionally strong magnetic fields that exceed 6000 G.
In this study, we carry out high-resolution RMHD simulations. The delta-type sunspot is spontaneously generated by large-scale convection, and we find a super-strong magnetic field (>6000 G) between positive and negative magnetic fields. The generation mechanism of the strong magnetic field is a shearing motion of the sunspot. Reconnected magnetic flux above the strong magnetic field maintains the strong field even in the low-beta region. The origin of the shearing motion is located at the deep convection zone. The huge energy in the deep convection zone is used to generate a strong magnetic field at the surface.