Dipolar stability in spherical simulations: The impact of an inner stable zone
Abstract
Magnetic fields vary in complexity for different stars. The stability of dipolar magnetic fields is known to depend on different quantities, e.g., the stellar rotation, the stratification, and the intensity of convective motions. Here, we study the dipolar stability in a system with an inner stable zone. We present preliminary results of dynamo simulations using the Rayleigh number as a control parameter. The stiffness of the stable zone is accordingly varied to keep a constant ratio of the BruntVäisälä frequency to the angular velocity. Similarly to the completely convective spherical shell, we find that a transition exists between a regime where the magnetic field is dipolar to a multipolar regime when the Rossby number is increased. The value of the Rossby number at the transition is very close to the one of the fully convective case.
 Publication:

Solar and Stellar Magnetic Fields: Origins and Manifestations
 Pub Date:
 2020
 DOI:
 10.1017/S1743921319009803
 arXiv:
 arXiv:1911.13285
 Bibcode:
 2020IAUS..354..185Z
 Keywords:

 Star: magnetic field;
 Stellar interiors: stablystratified;
 Dynamo: simulation;
 Astrophysics  Solar and Stellar Astrophysics;
 Physics  Fluid Dynamics
 EPrint:
 4 pages, 5 figs, IAU 354, proceedings