Affiliation
Max Planck Institute for Solar System Research
Main category
Natural Sciences (Astrophysics and Astrononmy)
Abstract
The magnetic field in the Sun undergoes a cyclic modulation with a reversal typically every 11 years due to a dynamo operating under the surface. We simulate a solar-type star, where the interplay between convection and rotation self-consistently drives large-scale magnetic field. We apply the test-field method to characterize the dynamo mechanism acting in this simulation by determining 27 turbulent transport coefficients of the electromotive force, of which 9 are related to the $\alpha$ effect tensor. We find that the alpha-effect has a complex nature and does not follow the profile expected from kinetic helicity. Besides the dominant $\alpha$-$\Omega$ dynamo, also an $\alpha^2$ dynamo is locally enhanced. The turbulent pumping velocities significantly alter the effective mean flows acting on the magnetic field and therefore challenge the flux transport dynamo concept. All coefficients are significantly affected due to dynamically important magnetic fields with quenching as well as enhancement being observed. This leads to a modulation of the coefficients with the activity cycle.
Further reading
https://arxiv.org/abs/1601.03730
Do you have problems viewing the pdf-file? Download presentation
here
If the presentation contains inappropriate content, please
report the presentation. You will be redirected to the landing page.
