Flux transport dynamos

Flux transport dynamos are one specific variety of hydromagnetic dynamos models for the Sun and stars. They provide a modelling framework for the spatiotemporal evolution of the Sun's large-scale magnetic field (spatial scales commensurate with the solar radius), on long timecales (many months to century and millenia). Their two primary defining features are:  the observed equator ward migration of sunspot source regions and poleward migration of surface fields are both driven by the "conveyor belt" action of the meridional flow;  the cycle period is primarily set by the meridional flow speed. Flux transport dynamos reproduce fairly well and robustly many observed solar cycle features, and are relatively well-constrained observationally. Their dynamical behavior, driven at least in part by a time-delay in the dynamo regenerative loop, also offers a natural explanation for the significant fluctuations observed in overall activity levels on decadal to millenial timescales.