THE PHASE OF THE RADIAL MEAN-FIELD IN THE SOLAR DYNAMO

Observations indicate that the radial and azimuthal components of the mean solar magnetic field oscillate with a phase shift of approximately 180 degrees during the 22-year cycle. In order to calculate such phase shifts we construct a simple two-dimensional, nonlinear alpha(2) Omega dynamo, which operates in the overshoot region beneath the convection zone. Like previous models, our model predicts an almost in-phase oscillation for most parameter choices. Special configurations, in which the two components of the mean,field have different distributions in latitude, may resolve the dilemma. Alternative conclusions are that our knowledge of the alpha effect is insufficient, or that the observational result is not reliable.