Impact of subsurface convective flows on the formation of sunspot magnetic field and energy build-up

Strong solar flares occur in -spots characterized by the complicated distribution of opposite-polarity magnetic fluxes in a single penumbra. Sunspots are formed as a result of flux emergence from the convection zone to the photosphere. Sunspot formation can be strongly affected by convective turbulent flows as well as the magnetic properties of flux tubes. It has not yet been shown how crucial convective flows are for the formation of -spots. The aim of this study is to reveal the impact of convective flows in the convection zone on the formation and evolution of sunspot magnetic fields. We simulated the transport of magnetic flux tubes in the convection zone using radiative magnetohydrodynamics code R2D2. We carried out 93 simulations by allocating the flux tubes to different positions in the convection zone. As a result, both -type and -type magnetic distributions were reproduced only by the differences in the convective flows surrounding the flux tubes. We detected a strong correlation between the distribution of the nonpotential magnetic field in the photosphere and the position of the downflow plume in the convection zone. The correlation could be detected 20–30 h before the flux emergence. The results suggest that high free energy regions in the photosphere can be predicted even before the magnetic flux appears in the photosphere by detecting the downflow profile in the convection zone.