Hydrodynamica l S imula t ions of the Solar Dynamo

Abst ract: Hydrodynamic simulations of the solar convection zone can be used to model the generation of differential rotation and magnetic fields, and to determine mean-field transport coefficients that are needed in mean-field models. The importance of the over-shoot layer beneath the solar convection zone is discussed: it is the place where the magnetic field accumulates, although most of the field regeneration can still occur in the convection zone proper. We also discuss how systematically oriented bipolar regions can emerge from the convection zone where the magnetic field is highly intermittent.