Long-term variations in solar meridional circulation from geomagnetic data: implications for solar dynamo theory

Abstract

Geomagnetic activity has two main peaks in the 11-year sunspot cycle caused by two types of solar agents: coronal mass ejections and high speed solar wind streams, whose variations in number and intensity are related to the variations in solar toroidal and poloidal fields, respectively. From the long-term variations in the lag between the two aa-index peaks we derive the long-term variations in solar meridional circulation. We use these relations to test the flux-transport solar dynamo theory and to explain some well known characteristics of the solar cycle. Based on these relations, we give a prediction for the amplitude (125) and epoch of the maximum (April 2011) of sunspot cycle 24.