Astronomy and Astrophysics – Astronomy
Scientific paper
Oct 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003apj...596..663z&link_type=abstract
The Astrophysical Journal, Volume 596, Issue 1, pp. 663-679.
Astronomy and Astrophysics
Astronomy
18
Sun: Magnetic Fields
Scientific paper
A fully three-dimensional, nonlinear, time-dependent spherical interface dynamo is investigated using a finite-element method based on the three-dimensional tetrahedralization of the spherical system. The spherical interface dynamo model consists of four zones: an electrically conducting and uniformly rotating core, a thin differentially rotating tachocline, a uniformly rotating turbulent convection envelope, and a nearly insulating exterior. The four regions are coupled magnetically through matching conditions at the interfaces. Without the effect of a tachocline, the conventional nonlinear α2 dynamo is always stationary, axisymmetric, and equatorially antisymmetric even though numerical simulations are always fully three-dimensional and time dependent. When there is no tachocline, the azimuthal field is confined to the convection zone while the poloidal magnetic field penetrates into the radiative core. The effects of an interface dynamo with a tachocline having a purely axisymmetric toroidal velocity field are as follows: (1) the action of the steady tachocline always gives rise to an oscillatory dynamo with a period of about 2 magnetic diffusion units, or about 20 yr if the magnetic diffusivity in the convection zone is 108 m2 s-1 (2) the interface dynamo solution is always axisymmetric, selects dipolar symmetry, and propagates equatorward (for the assumed form of α) although the simulation is fully three-dimensional (3) the generated magnetic field mainly concentrates in the vicinity of the interface between the tachocline and the convection zone; and (4) the strength of the toroidal magnetic field is dramatically amplified by the effect of the tachocline. Extensions of Cowling's theorem and the toroidal flow theorem to multilayer spherical shell regions with radially discontinuous magnetic diffusivities are presented.
Chan Ho Kei
Liao Xia
Schubert Gerald
Zhang Kaicheng
Zou Jian
No associations
LandOfFree
A Three-dimensional Spherical Nonlinear Interface Dynamo does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Three-dimensional Spherical Nonlinear Interface Dynamo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Three-dimensional Spherical Nonlinear Interface Dynamo will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-913433