Loading…

Numerical simulations of kinematic dynamo action

Numerical simulations of kinematic dynamo action in steady and three-dimensional ABC flows are presented with special focus on the difference in growth rates between cases with single and multiple periods of the prescribed velocity field. It is found that the difference in growth rate (apart from a...

Full description

Saved in:
Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2003-01, Vol.397 (2), p.393-399
Main Authors: Archontis, V., Dorch, S. B. F., Nordlund, Ă….
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Numerical simulations of kinematic dynamo action in steady and three-dimensional ABC flows are presented with special focus on the difference in growth rates between cases with single and multiple periods of the prescribed velocity field. It is found that the difference in growth rate (apart from a trivial factor stemming from a scaling of the rate of strain with the wavenumber of the velocity field) is due to differences in the recycling of the weakest part of the magnetic field. The single wavelength classical ABC-flow experiments impose stronger symmetry requirements, which results in a suppression of the growth rate. The experiments with larger wave number achieve growth rates that are more compatible with the turn-over time scale by breaking the symmetry of the resulting dynamo-generated magnetic field. Differences in topology in cases with and without stagnation points in the imposed velocity field are also investigated, and it is found that the cigar-like structures that develop in the classical $A=B=C$ dynamos are replaced by ribbon structures in cases where the flow is without stagnation points.
ISSN:0004-6361
1432-0746
DOI:10.1051/0004-6361:20021568