On global solar dynamo simulations
arXiv:1010.1249 · doi:10.1002/asna.201012345
Abstract
Global dynamo simulations solving the equations of magnetohydrodynamics (MHD) have been a tool of astrophysicists who try to understand the magnetism of the Sun for several decades now. During recent years many fundamental issues in dynamo theory have been studied in detail by means of local numerical simulations that simplify the problem and allow the study of physical effects in isolation. Global simulations, however, continue to suffer from the age-old problem of too low spatial resolution, leading to much lower Reynolds numbers and scale separation than in the Sun. Reproducing the internal rotation of the Sun, which plays a crucual role in the dynamo process, has also turned out to be a very difficult problem. In the present paper the current status of global dynamo simulations of the Sun is reviewed. Emphasis is put on efforts to understand how the large-scale magnetic fields, i.e. whose length scale is greater than the scale of turbulence, are generated in the Sun. Some lessons from mean-field theory and local simulations are reviewed and their possible implications to the global models are discussed. Possible remedies to some current issues of solar simulations are put forward.
8 pages, published version
References in corpus (37)
- The inverse cascade and nonlinear alpha-effect in simulations of isotropic helical hydromagnetic turbulence
- Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope
- The case for a distributed solar dynamo shaped by near-surface shear
- Turbulent Convection Under the Influence of Rotation: Sustaining a Strong Differential Rotation
- Magnetic field generation in fully convective rotating spheres
- Mean-field concept and direct numerical simulations of rotating magnetoconvection and the geodynamo
- Persistent Magnetic Wreaths in a Rapidly Rotating Sun
- Structure and Evolution of Giant Cells in Global Models of Solar Convection
- Solar differential rotation and meridional flow: The role of a subadiabatic tachocline for the Taylor-Proudman balance
- Dynamo Action in the Solar Convection Zone and Tachocline: Pumping and Organization of Toroidal Fields
- Magnetic diffusivity tensor and dynamo effects in rotating and shearing turbulence
- Electromotive Force and Large-Scale Magnetic Dynamo in a Turbulent Flow with a Mean Shear
- Rapidly Rotating Suns and Active Nests of Convection
- Nonlinear theory of a "shear-current" effect and mean-field magnetic dynamos
- Large-scale dynamos in turbulent convection with shear
- The Nuclear Stellar Disk in Andromeda: A Fossil from the Era of Black Hole Growth
- Generation of Magnetic Field by Combined Action of Turbulence and Shear
- Magnetoconvection and dynamo coefficients: II. Field-direction dependent pumping of magnetic field
- Alpha effect and turbulent diffusion from convection
- Magnetoconvection and dynamo coefficients: Dependence of the alpha-effect on rotation and magnetic field
- Large-scale Dynamo Action Driven by Velocity Shear and Rotating Convection
- Large-scale dynamos at low magnetic Prandtl numbers
- Large-scale dynamos in rigidly rotating turbulent convection
- Magnetoconvection and dynamo coefficients III: alpha-effect and magnetic pumping in the rapid rotation regime
- A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone
- Oscillatory migrating magnetic fields in helical turbulence in spherical domains
- Oscillatory mean-field dynamos with spherically symmetric, isotropic alpha
- Turbulent dynamos in spherical shell segments of varying geometrical extent
- The eddy heat-flux in rotating turbulent convection
- Do spherical alpha^2-dynamos oscillate?
- A model of the entropy flux and Reynolds stress in turbulent convection
- The alpha effect with imposed and dynamo-generated magnetic fields
- The alpha effect in rotating convection with sinusoidal shear
- Open and closed boundaries in large-scale convective dynamos
- Reynolds stresses from hydrodynamic turbulence with shear and rotation
- Three-dimensional stability of the solar tachocline
- Strong Dynamo Action in Rapidly Rotating Suns
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- Cyclic magnetic activity due to turbulent convection in spherical wedge geometry
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- Numerical simulations of quiet Sun magnetic fields seeded by Biermann battery
- Oscillatory large-scale dynamos from Cartesian convection simulations
- A finite-volume scheme for modeling compressible magnetohydrodynamic flows at low Mach numbers in stellar interiors
- Prandtl number dependence of compressible convection: Flow statistics and convective energy transport
- Convective Differential Rotation in Stars and Planets I: Theory
- Convective Differential Rotation in Stars and Planets II: Observational and Numerical Tests