CYCLE TIMES AND MAGNETIC AMPLITUDES IN NONLINEAR 1D ALPHA(2)OMEGA-DYNAMOS

A nonlinear, 1D-slab, alpha(2) Omega-dynamo is analysed for magnetic f ield amplitudes and for the relation between the cycle time and the dy namo number. If the only nonlinearity is the conventional ct-quenching , the magnetic field strongly grows with the dynamo number, while the dependence of the cycle time is only rather weak. The opposite is true if the nonlinear feedback is more consistently included: the complete effect of the turbulent EMF tensor is deformed and suppressed by the induced large-scale magnetic field. In particular, this involves eta-q uenching where the eddy diffusivity becomes a tensor whose components are different functions of the magnetic field. Thus, the magnetic fiel d amplitude only scales with the small value \m'\ less than or similar to 0.2 while the cycle oscillation frequency depends much more strong ly on the dynamo number (n' similar or equal to 0.5). The latter seems to be consistent with the results of the Mt. Wilson HK-project for st ellar activity cycles, although our dynamo model only forms a rather r ough approximation for stellar configurations.