Calculations for mean field dynamo models (in both full spheres and spherical
shells), with both algebraic and dynamic α--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 α 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