Ejections of magnetic structures above a spherical wedge driven by a convective dynamo with differential rotation
arXiv:1112.0505 · doi:10.1007/s11207-012-0108-4
Abstract
We combine a convectively driven dynamo in a spherical shell with a nearly isothermal density-stratified cooling layer that mimics some aspects of a stellar corona to study the emergence and ejections of magnetic field structures. This approach is an extension of earlier models, where forced turbulence simulations were employed to generate magnetic fields. A spherical wedge is used which consists of a convection zone and an extended coronal region to times the radius of the sphere. The wedge contains a quarter of the azimuthal extent of the sphere and $150\degr$ in latitude. The magnetic field is self-consistently generated by the turbulent motions due to convection beneath the surface. Magnetic fields are found to emerge at the surface and are ejected to the coronal part of the domain. These ejections occur at irregular intervals and are weaker than in earlier work. We tentatively associate these events with coronal mass ejections on the Sun, even though our model of the solar atmosphere is rather simplistic.
25 pages, 17 figures, published in Solar Physics
References in corpus (16)
- Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope
- Magnetic field generation in fully convective rotating spheres
- Simulations of core convection in rotating A-type stars: Magnetic dynamo action
- Nonlinear force-free modeling of the solar coronal magnetic field
- Cyclic magnetic activity due to turbulent convection in spherical wedge geometry
- Twisted flux tube emergence from the convection zone to the corona
- Large-scale dynamos in turbulent convection with shear
- Buoyant Magnetic Loops in a Global Dynamo Simulation of a Young Sun
- Reynolds stress and heat flux in spherical shell convection
- Small-scale magnetic helicity losses from a mean-field dynamo
- Dynamo-driven plasmoid ejections above a spherical surface
- Catastrophic alpha quenching alleviated by helicity flux and shear
- 3D Reconstruction of a Rotating Erupting Prominence
- Effects of stratification in spherical shell convection
- Magnetic helicity fluxes in an alpha-squared dynamo embedded in a halo
- Surface appearance of dynamo-generated large-scale fields
Cited by in corpus (15)
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- Dynamo cycles in global convection simulations of solar-like stars
- Influence of a coronal envelope as a free boundary to global convective dynamo simulations
- Magnetic twist: a source and property of space weather
- Bipolar region formation in stratified two-layer turbulence
- Current systems of coronal loops in 3D MHD simulations
- A new look at sunspot formation using theory and observations
- Coronal influence on dynamos
- Dynamos and Differential Rotation: Advances at the Crossroads of Analytics, Numerics, and Observations
- Magnetic bipoles in rotating turbulence with coronal envelope
- Solar-like differential rotation and equatorward migration in a convective dynamo with a coronal envelope
- Coronal ejections from convective spherical shell dynamos