Generation of solar magnetic fields by the αδΩ dynamo

We consider a solar dynamo mechanism that generates large-scale magnetic fields due to the combined action of cyclonic flows (the alpha effect), differential rotation (the Omega effect), and the non-uniformity of large-scale magnetic fields (the Omega x J effect). Our results are based on numerical model which takes into account currently available data on the differential rotation of the convection zone and the intensity of convective flows in the solar interior. A reasonable choice of parameters characterizing the intensity of magnetic-field generation by the alpha and Omega x J mechanisms can account for an oscillatory dynamo regime with properties similar to the 22-year magnetic-activity cycle of the Sun. We analyze the nonlinear saturation of the generation effects in the large-scale magnetic field, due to either magnetic stresses or the conservation of magnetic helicity. Allowance for the helicity of the small-scale magnetic fields is of crucial importance in limiting the energy of the generated large-scale magnetic field.