Small-Scale Surface Flows and their Implications for Solar Activity

The broad range of dynamics exhibited by plasma motions within the solar interior affects many aspects of the generation and transport of magnetic fields during the solar magnetic activity cycle. On the photosphere, such dynamics include the differential rotation, meridional flows, and a hierarchy of convection cells, and these fluid motions are observed to readily advect any small-scale magnetic fields embedded within them. While the effects of large-scale flows on the global activity cycle are well known, it is becoming increasingly apparent that small-scale dynamics can also affect global magnetic activity throughout the solar cycle. Such effects include variations in the strength of the magnetic dipole moment with time, and the timing of the reversals of the polar-cap flux. In this article, several aspects of this coupling between small and large scales will be illustrated, and the implications of such coupling on the solar activity cycle will be discussed.