Non-linear alpha-omega-dynamos driven by magnetic buoyancy

An alpha-omega-dynamo with an alpha-effect based on magnetic buoyancy instabilities is described. This alpha-effect has one main advantage over previous descriptions, namely, that it is derived from a numerical model of the physical processes that are thought to occur at the base of the convection zone. We investigate a 1D and a 1D alpha-omega-dynamo in a cylindrical and a spherical shell, respectively. In both models the omega-effect is described by a simple shear flow, while alpha is proportional to the radial gradient of the magnetic field because, simply speaking, this gradient determines when magnetic buoyancy instabilities occur and hence when the alpha-effect sets in. (Author)