Modeling the solar cycles 12-20 with a realistic Babcock-Leighton flux transport dynamo

Jiang Jie, jiejiang@nao.cas.cn, NAOC, China
Cameron Robert, MPS
Isik Emre, Department of Physics, Faculty of Science and Letters, Istanbul Culture University


Abstract
The Babcock-Leighton (BL) type flux transport dynamo (FTD) has demonstrated itself the most promising model to explain the evolution of the solar magnetic field. The generation of the poloidal field in the BL-type dynamo, i.e. the alpha-effect, is caused by the decay of bipolar sunspot groups on the solar surface, which was simply treated by the alpha-coeffient or the double ring method in previous studies. we set up a realistic BL FTD for the first time to simulate the cycle amplitude variations for solar cycles 12-20. The surface poloidal field is derived from the surface flux transport (SFT) model with the observed sunspot group areas data as input. This provides the source of the alpha term in the FTD. The radial outer boundary condition is used in the FTD to be consistent with SFT. The diamagnetic pumping is included based on the constrain by Cameron et al. (2012). The cycle amplitudes and the dominated dipolar magnetic fields for cycles 12-20 are well reproduced. Our results indicate that it is the radial inward pumping which carried the surface poloidal field downward to the base of convective zone in about 5-7 yr and further is responsible for the correlation between polar field and the next cycle strength.