On the compatibility of a flux transport dynamo with a fast tachocline scenario

TL;DR

This paper demonstrates that a flux transport dynamo model can be compatible with a fast tachocline scenario, aligning well with helioseismic observations and maintaining solar-like magnetic cycle features.

Contribution

It introduces a coupled flux transport dynamo model with a feedback mechanism linking tachocline thickness to magnetic field strength, showing robustness and agreement with seismic data.

Findings

Dynamo model remains robust with fast tachocline feedback.

Tachocline thickness matches helioseismic constraints.

Latitude-dependent thickness aligns with seismic observations.

Abstract

The compatibility of the fast tachocline scenario with a flux transport dynamo model is explored. We employ a flux transport dynamo model coupled with simple feedback formulae relating the thickness of the tachocline to the amplitude of the magnetic field or to the Maxwell stress. The dynamo model is found to be robust against the nonlinearity introduced by this simplified fast tachocline mechanism. Solar-like butterfly diagrams are found to persist and, even without any parameter fitting, the overall thickness of the tachocline is well within the range admitted by helioseismic constraints. In the most realistic case of a time and latitude dependent tachocline thickness linked to the value of the Maxwell stress, both the thickness and its latitude dependence are in excellent agreement with seismic results. In the nonparametric models, cycle related temporal variations in tachocline thickness are somewhat larger than admitted by helioseismic constraints; we find, however, that introducing a further parameter into our feedback formula readily allows further fine tuning of the thickness variations.