Toroidal field instability and eddy viscosity in Taylor-Couette flows
arXiv:0809.0414 · doi:10.1002/asna.200811020
Abstract
Toroidal magnetic fields subject to the Tayler instability can transport angular momentum. We show that the Maxwell and Reynolds stress of the nonaxisymmetric field pattern depend linearly on the shear in the cylindrical gap geometry. Resulting angular momentum transport also scales linear with shear. It is directed outwards for astrophysical relevant flows and directed inwards for superrotating flows with dOmega/dR>0. We define an eddy viscosity based on the linear relation between shear and angular momentum transport and show that its maximum for given Prandtl and Hartmann number depends linear on the magnetic Reynolds number Rm. For Rm=1000 the eddy viscosity is of the size of 30 in units of the microscopic value.
5 pages, 6 figures
References in corpus (8)
- Single star progenitors of long gamma-ray bursts I: Model grids and redshift dependent GRB rate
- On magnetic instabilities and dynamo action in stellar radiation zones
- Binary star progenitors of long gamma-ray bursts
- Stellar evolution with rotation and magnetic fields:III: The interplay of circulation and dynamo
- A differential rotation driven dynamo in a stably stratified star
- Destabilisation of hydrodynamically stable rotation laws by azimuthal magnetic fields
- Helicity generation and alpha-effect by Vandakurov-Tayler instability with z-dependent differential rotation
- How Efficient is Rotational Mixing in Massive Stars ?