Simple solar dynamo models with variable alpha and omega effects
Abstract
We examine a pair of radially averaged, pseudo-Cartesian dynamo models, one with a dynamically variable alpha effect, and the other with a dynamically variable omega effect. Our models are kept deliberately minimal in order to permit extensive numerical analysis, including in particular direct solution of periodic orbits and continuation of unstable branches. Despite some differences in the formulations used, the bifurcation structure of the variable-omega model is found to resemble closely that computed by Jennings & Weiss, whereas that of the variable-alpha model matches the structure computed by Schmalz & Stix somewhat less well. Our two systems, however, resemble each other not at all, despite having the same linearized form. Quenching of the alpha and omega effects is confirmed to have dramatically different effects, with omega-quenching perhaps producing better resemblance to the Sun. Also, we find the variable-alpha model to contain periodic solutions for positive dynamo number that do not show poleward propagation, contrary to conventional wisdom.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 1997
- DOI:
- 10.1093/mnras/288.3.551
- Bibcode:
- 1997MNRAS.288..551R
- Keywords:
-
- CHAOS;
- MHD;
- SUN: ACTIVITY;
- SUN: MAGNETIC FIELDS;
- SUN: ROTATION;
- STARS: MAGNETIC FIELDS