MHD simulations of penumbra fine structure

Abstract

We present results of numerical 3D MHD simulations with radiative energy transfer of fine structure in a small sunspot of about 4 Mm width. The simulations show the development of filamentary structures and flow patterns that are, except for the lengths of the filaments, very similar to those observed. The filamentary structures consist of gaps with reduced field strength relative to their surroundings. Calculated synthetic images show dark cores like those seen in the observations; the dark cores are the result of a locally elevated $\tau =1$ surface. The magnetic field in these cores is weaker and more horizontal than for adjacent brighter structures, and the core support a systematic outflow. Movies show migration of the dark-cored structures towards the umbra, and fragments of magnetic flux that are carried away from the spot by a large scale `moat flow'. We conclude that the simulations are in qualitative agreement with observed penumbra filamentary structures, Evershed flows and moving magnetic features.

6 pages, 7 figures, submitted to ApJ

References in corpus (6)

• Magneto-convection in a sunspot umbra
• Observational manifestations of solar magneto-convection -- center-to-limb variation
• Fine structure, magnetic field and heating of sunspot penumbrae
• Magnetostatic penumbra models with field-free gaps
• A dynamical model for the penumbral fine structure and the Evershed effect in sunspots
• Radiative transfer in decomposed domains

Cited by in corpus (77)

• The stellar atmosphere simulation code Bifrost
• Simulations of stellar convection with CO5BOLD
• Radiative MHD simulation of sunspot structure
• Simulation of the Formation of a Solar Active Region
• Local Helioseismology: Three Dimensional Imaging of the Solar Interior
• Penumbral structure and outflows in simulated sunspots
• Numerical sunspot models: Robustness of photospheric velocity and magnetic field structure
• Flocculent flows in the chromospheric canopy of a sunspot
• Numerical simulations of active region scale flux emergence: From spot formation to decay
• Penumbral fine structure and driving mechanisms of large-scale flows in simulated sunspots
• A Radiation Transfer Solver for Athena using Short Characteristics
• Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)
• Modeling the Subsurface Structure of Sunspots
• Subsurface magnetic field and flow structure of simulated sunspots
• Emergence of magnetic flux generated in a solar convective dynamo. I: Formation of Sunspots and Active regions, and Origin of Their Asymmetries
• Monte Carlo Radiation Hydrodynamics with Implicit Methods
• High accretion rates in magnetised Keplerian discs mediated by a Parker instability driven dynamo
• Opposite polarity field with convective downflow and its relation to magnetic spines in a sunspot penumbra
• Convection and the origin of Evershed flows in sunspot penumbrae
• Numerical simulations of sunspot decay: On the penumbra -- Evershed flow -- moat flow connection
• Short dynamic fibrils in sunspot chromospheres
• A model for the formation of the active region corona driven by magnetic flux emergence
• Detection of sea-serpent field lines in sunspot penumbrae
• A geometrical height scale for sunspot penumbrae
• On the velocity field of sunspot penumbrae - I. A global view
• Upflows in the central dark lane of sunspot light bridges
• On the emergence of toroidal flux tubes: general dynamics and comparisons with the cylinder model
• Large-scale magnetic flux concentrations from turbulent stresses
• Traveling Waves of Magnetoconvection and the Origin of the Evershed Effect in Sunspots
• On the Absence of Photospheric Net Currents in Vector Magnetograms of Sunspots Obtained From Hinode (SOT/SP)
• Properties of simulated sunspot umbral dots
• Heat transfer in sunspot penumbrae. Origin of dark-cored penumbral filaments
• Characteristic Dependence of Umbral Dots on their Magnetic Structure
• Temporal Evolution of Velocity and Magnetic Field in and around Umbral Dots
• Local Helioseismology of Sunspots: Current Status and Perspectives (Invited Review)
• Sunspots: from small-scale inhomogeneities towards a global theory
• Normal and counter Evershed flows in the photospheric penumbra of a sunspot. SPINOR 2D inversions of Hinode-SOT/ SP observations
• The photospheric environment of a solar pore with light bridge
• Striation and convection in penumbral filaments
• Lateral downflows in sunspot penumbral filaments and their temporal evolution
• Near-polytropic simulations with a radiative surface
• Models and Observations of Sunspot Penumbrae
• SST/CRISP Observations of Convective Flows in a Sunspot Penumbra
• Evidence for convection in Sunspot penumbrae
• Solar Dynamics, Rotation, Convection and Overshoot
• Explanation of the sea-serpent magnetic structure of sunspot penumbrae
• Evershed and counter-Evershed flows in sunspot MHD simulations
• Disintegration of Magnetic Flux in Decaying Sunspots as Observed with the Hinode SOT
• Searching for overturning convection in penumbral filaments: slit spectroscopy at 0.2 arcsec resolution
• Dark structures in sunspot light bridges
• Convective motions and net circular polarization in sunspot penumbrae
• Restoring process of sunspot penumbra
• Can overturning motions in penumbral filaments be detected?
• Waves as the source of apparent twisting motions in sunspot penumbrae
• Observations of Umbral Dots and their Physical Models
• The Evershed Effect with SOT/Hinode
• Convection and the Origin of Evershed Flows
• Penumbral thermal structure below the visible surface
• The Evershed Flow and the Brightness of the Penumbra
• Long-Term Evolution of Three Light Bridges Developed on the Same Sunspot
• Hydraulic effects in a radiative atmosphere with ionization
• Solar magneto-convection
• Sunspot Bright Points
• Recent Evidence for Convection in Sunspot Penumbrae
• 3D numerical MHD modeling of sunspots with radiation transport
• The formation of a penumbra as observed with the German VTT and SoHO/MDI
• The time step constraint in radiation hydrodynamics
• A Topology for the Penumbral Magnetic Fields
• Turbulent radiative diffusion and turbulent Newtonian cooling
• The Current State-Of-The-Art In Active Region Seismology
• Recipe for inferring sub-surface solar magnetism via local mode-coupling using Slepian basis functions
• Temporal Relation between Disappearance of Penumbral Fine-Scale Structure and Evershed Flow
• Response to "Stray-light correction in 2D spectroscopy" by R. Schlichenmaier and M. Franz
• Umbral Dynamics in the Near Infrared Continuum
• Theoretical Models of Sunspot Structure and Dynamics
• Sunspot simulations with MURaM -- I. Parameter study using potential field initial conditions
• Similarities of magnetoconvection in the umbra and in the penumbra of sunspots