Local models of stellar convection: Reynolds stresses and turbulent heat transport
arXiv:astro-ph/0312376 · doi:10.1051/0004-6361:20035874
Abstract
We study stellar convection using a local three-dimensional MHD model, with which we investigate the influence of rotation and large-scale magnetic fields on the turbulent momentum and heat transport. The former is studied by computing the Reynolds stresses, the latter by calculating the correlation of velocity and temperature fluctuations, both as functions of rotation and latitude. We find that the horisontal correlation, Q_(theta phi), capable of generating horisontal differential rotation, is mostly negative in the southern hemisphere for Coriolis numbers exceeding unity, corresponding to equatorward flux of angular momentum in accordance with solar observations. The radial component Q_(r phi) is negative for slow and intermediate rotation indicating inward transport of angular momentum, while for rapid rotation, the transport occurs outwards. Parametrisation in terms of the mean-field Lambda-effect shows qualitative agreement with the turbulence model of Kichatinov & Rüdiger (1993) for the horisontal part H \propto Q_(theta phi)/cos(theta), whereas for the vertical part, V \propto Q_(r phi)/sin(theta), agreement only for intermediate rotation exists. The Lambda-coefficients become suppressed in the limit of rapid rotation, this rotational quenching being stronger for the V component than for H. We find that the stresses are enhanced by the presence of the magnetic field for field strengths up to and above the equipartition value, without significant quenching. Concerning the turbulent heat transport, our calculations show that the transport in the radial direction is most efficient at the equatorial regions, obtains a minimum at midlatitudes, and shows a slight increase towards the poles. The latitudinal heat transport does not show a systematic trend as function of latitude or rotation.
26 pages, 20 figures, final published version. For a version with higher resolution figures, see http://cc.oulu.fi/~pkapyla/publ.html
References in corpus (8)
- Turbulent Convection Under the Influence of Rotation: Sustaining a Strong Differential Rotation
- Parity properties of an advection-dominated solar $α^2\Om$-dynamo
- Magnetoconvection and dynamo coefficients: II. Field-direction dependent pumping of magnetic field
- Non-Fickian diffusion and tau approximation from numerical turbulence
- Differential rotation in rapidly rotating F-stars
- Magnetoconvection and dynamo coefficients: Dependence of the alpha-effect on rotation and magnetic field
- A 3D MHD model of astrophysical flows: algorithms, tests and parallelisation
- A Large Eddy Simulation of Turbulent Compressible Convection: Differential Rotation in the Solar Convection Zone
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