The Maunder Minimum as Due to Magnetic Λ-quenching

We study the nonlinear interplay between dynamo-induced magnetic fields and differential rotation in stellar con-vection zones. The magnetic back reaction is threefold: Lorentz force, α-quenching and Λ-quenching. If only the Malkus-Proctor feedback is used, the dynamo shows an interesting non-periodic behavior which, however, disappears when α quenching is included (cf. Fig. 2). If also a strong Λ-quenching is allowed to modify the differential rotation, the dynamo resumes its exotic performance with periodically changing cycle periods and fluctuating magnetic parities. The Elsasser number has been set to unity whereas the magnetic Prandtl number must be smaller than unity. For too small magnetic Prandtl numbers (e.g. for Pm = 0.01), however, the grand minima seldom occur.