3D numerical MHD modeling of sunspots with radiation transport

Abstract

Sunspot fine structure has been modeled in the past by a combination of idealized magneto-convection simulations and simplified models that prescribe the magnetic field and flow structure to a large degree. Advancement in numerical methods and computing power has enabled recently 3D radiative MHD simulations of entire sunspots with sufficient resolution to address details of umbral dots and penumbral filaments. After a brief review of recent developments we focus on the magneto-convective processes responsible for the complicated magnetic structure of the penumbra and the mechanisms leading to the driving of strong horizontal outflows in the penumbra (Evershed effect). The bulk of energy and mass is transported on scales smaller than the radial extent of the penumbra. Strong horizontal outflows in the sunspot penumbra result from a redistribution of kinetic energy preferring flows along the filaments. This redistribution is facilitated primarily through the Lorentz force, while horizontal pressure gradients play only a minor role. The Evershed flow is strongly magnetized: While we see a strong reduction of the vertical field, the horizontal field component is enhanced within filaments.

7 pages, 2 figures, proceedings IAU S 273

References in corpus (6)

• Magneto-convection in a sunspot umbra
• Penumbral structure and outflows in simulated sunspots
• MHD simulations of penumbra fine structure
• Convection and the origin of Evershed flows in sunspot penumbrae
• Traveling Waves of Magnetoconvection and the Origin of the Evershed Effect in Sunspots
• The Fine-Structure of the Net-Circular Polarization in a Sunspot Penumbra

Cited by in corpus (6)

• Penumbral fine structure and driving mechanisms of large-scale flows in simulated sunspots
• Subsurface magnetic field and flow structure of simulated sunspots
• Probing the Physics of the Solar Atmosphere with the Multi-slit Solar Explorer (MUSE): II. Flares and Eruptions
• On Molecular Hydrogen Formation and the Magnetohydrostatic Equilibrium of Sunspots
• The problem of the height dependence of magnetic fields in sunspots
• Can overturning motions in penumbral filaments be detected?