Competing local and non-local α-effects for a simplified flux transport dynamo model




The solar magnetic field is maintained by a hydromagnetic dynamo, and it is generally accepted that strong toroidal magnetic field is produced at the tachocline below the solar convection zone. The location of production of the poloidal field via the α-effect is still in question. One such location is the solar surface, where decay of bipolar magnetic regions produces poloidal magnetic field; this is known as the Babcock–Leighton mechanism. Another possible location is the base of the solar convection zone. Recent work has looked at the competition in the solar dynamo between surface and deep-seated α-effects. The α-effects studied were local effects. However, flux-transport dynamo calculations use non-local poloidal source terms, that is they act at the surface but are proportional to the toroidal field at the base of the convection zone. We will discuss the effects of non-local competing α-effects on the dynamo equations to explore the validity of this type of model. We will also include the effects of meridional circulation.