Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-04-29
Astrophys.J. 579 (2002) 359-373
Astronomy and Astrophysics
Astrophysics
21 pages, 5 figures (revised version)
Scientific paper
10.1086/342705
We supplement the mean field dynamo growth equation with the total magnetic helicity evolution equation. This provides an explicitly time dependent model for alpha quenching in dynamo theory. For dynamos without shear, this approach accounts for the observed large scale field growth and saturation in numerical simulations. After a significant kinematic phase, the dynamo is resistively quenched, i.e. the saturation time depends on the microscopic resistivity. This is independent of whether or not the turbulent diffusivity is resistively quenched. We find that the approach is also successful for dynamos that include shear and exhibit migratory waves (cycles). In this case however, whether or not the cycle period remains of the order of the dynamical time scale at large magnetic Reynolds numbers does depend how on how the turbulent magnetic diffusivity quenches. Since this is unconstrained by magnetic helicity conservation, the diffusivity is presently an input parameter. Comparison to current numerical experiments suggests a turbulent diffusivity that depends only weakly on the magnetic Reynolds number, but higher resolution simulations are needed.
Blackman Eric G.
Brandenburg Axel
No associations
LandOfFree
Dynamic nonlinearity in large scale dynamos with shear 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 Dynamic nonlinearity in large scale dynamos with shear, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamic nonlinearity in large scale dynamos with shear will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-260449