Grand Minima Under the Light of a Low Order Dynamo Model

TL;DR

This study employs a low order dynamo model based on mean field theory to investigate the conditions under which solar grand minima can occur, emphasizing the roles of meridional circulation, diffusivity, and buoyancy.

Contribution

The paper introduces a non-linear oscillator dynamo model incorporating stochastic effects and identifies key physical processes influencing grand minima onset.

Findings

Stochastic fluctuations in a linear $\alpha$ effect do not trigger grand minima.

Mechanisms involving meridional circulation, diffusivity, or buoyancy are more likely triggers.

The model aligns with observed solar magnetic behavior and provides insights into grand minima dynamics.

Abstract

In this work we use a low order dynamo model and study under which conditions can it reproduce solar grand minima. We begin by building the phase space of a proxy for the toroidal component of the solar magnetic field and we develop a model, derived from mean field dynamo theory, that gives the time evolution of the toroidal field. This model is characterized by a non-linear oscillator whose coefficients retain most of the physics behind dynamo theory. In the derivation of the model we also include stochastic oscillations in the $\alpha$ effect. We found no evidences that stochastic fluctuations in a linear $\alpha$ effect can trigger grand minima episodes in this model. In contrast, the model used points out that possible mechanism that can trigger grand minima should involve the meridional circulation, magnetic diffusivity or field intensification by buoyancy driven instabilities.