Alleviation of catastrophic quenching in solar dynamo model with nonlocal alpha-effect

TL;DR

This paper demonstrates that a nonlocal alpha-effect in a solar dynamo model prevents catastrophic quenching, leading to sustainable magnetic field generation with realistic oscillation periods and symmetries.

Contribution

It introduces a dynamo model incorporating nonlocal alpha-effect, diamagnetic pumping, and magnetic alpha-effect dynamics, showing suppression of catastrophic quenching compared to local models.

Findings

Nonlocal alpha-effect prevents catastrophic quenching.

Magnetic fields exhibit dipolar symmetry and 10-year oscillations.

Toroidal-to-polar field ratio is approximately 1000.

Abstract

The nonlocal alpha-effect of Babcock-Leighton type is not prone to the catastrophic quenching due to conservation of magnetic helicity. This is shown with a dynamo model, which jointly applies the nonlocal alpha-effect, the diamagnetic pumping, and dynamical equation for the magnetic alpha-effect. The same model shows catastrophic quenching when the alpha-effect is changed to its local formulation. The nonlocal model shows the preferred excitation of magnetic fields of dipolar symmetry, which oscillate with a period of about ten years and have a toroidal-to-polar fields ratio of about a thousand.