 Babcock-Leighton mechanism

The Babcock-Leighton mechanism regenerates large-scale poloidal solar flux through the emergence and dispersal of systematically tilted bipolar active regions. With Joy's law tilt, opposite polarities have different latitudes: cancellation near the equator and poleward transport of surviving following-polarity flux alter and reverse the polar field. Thus a toroidal field that produces rising bipolar regions feeds back into a poloidal magnetic field. The source is intrinsically nonlocal between the interior flux reservoir and surface emergence and is stochastic because active-region fluxes and tilts vary.