The leading theoretical paradigm for the Sun’s magnetic cycle is an𝛼𝜔-dynamo process (Parker 1955), in which a combination of differential rotation and turbulent, helical flows produces a large-scale magnetic field that reverses every 11 years. Most𝛼𝜔solar dynamo models rely on differential rotation in the solar tachocline to generate a strong toroidal field. The most problematic part of such models is then the production of the large-scale poloidal field, via a process known as the𝛼-effect. Whilst this is usually attributed to small-scale convective motions under the influence of rotation, the efficiency of this regenerative process has been called into question by some numerical simulations (Cattaneo and Hughes 2006, Favier and Bushby 2011).

Motivated by likely conditions within the tachocline, we investigate an alternative mechanism for the poloidal field regeneration, namely the magnetic buoyancy instability in a shear-generated, rotating magnetic layer. Guided by our previous work (Duguid et al. 2023, 2024) we have used numerical simulations to investigate this mechanisms potential to operate as a solar-like dynamo.

In this talk I will first present results of our recent papers (Duguid et al. 2023, 2024) which explores the dynamics of a shear-generated magnetically buoyant layer under the influence of rotation in the non-dynamo context. I will then present our main result which is that this mechanism can produce a naturally migratory dynamo with many solar-like properties.