The treatment of magnetic buoyancy in flux transport dynamo models

TL;DR

This paper reviews the treatment of magnetic buoyancy in flux transport dynamo models, highlighting limitations of current methods and emphasizing the inherently 3D nature of the process.

Contribution

It critically compares local and non-local methods of modeling magnetic buoyancy, revealing their shortcomings and the need for more realistic 3D approaches.

Findings

Neither local nor non-local methods fully capture magnetic buoyancy.

Magnetic buoyancy is an inherently 3D process.

Unclear why sunspot emergence is limited to low latitudes.

Abstract

One important ingredient of flux transport dynamo models is the rise of the toroidal magnetic field through the convection zone due to magnetic buoyancy to produce bipolar sunspots and then the generation of the poloidal magnetic field from these bipolar sunspots due to the Babcock-Leighton mechanism. Over the years, two methods of treating magnetic buoyancy, a local method and a non-local method have been used widely by different groups in constructing 2D kinematic models of the flux transport dynamo. We review both these methods and conclude that neither of them is fully satisfactory, presumably because magnetic buoyancy is an inherently 3D process. We also point out so far we do not have proper understanding of why sunspot emergence is restricted to rather low latitudes.