Mean Field Dynamos with Algebraic and Dynamic alpha-Quenchings

Abstract

Calculations for mean field dynamo models (in both full spheres and spherical shells), with both algebraic and dynamic $\alpha$--quenchings, show qualitative as well as quantitative differences and similarities in the dynamical behaviour of these models. We summarise and enhance recent results with extra examples. Overall, the effect of using a dynamic $\alpha$ appears to be complicated and is affected by the region of parameter space examined.Comment: 6 pages, 2 postscript figures, also available at http://www.maths.qmw.ac.uk/~eo