Origin of solar magnetism

TL;DR

This paper reviews the flux transport dynamo model for solar magnetism, explaining its mechanisms, how it accounts for solar cycle features, irregularities, and the potential for predicting future solar activity based on polar field observations.

Contribution

It discusses the role of diffusivity in the convection zone and its impact on solar cycle prediction, highlighting the model's explanatory power for solar magnetic phenomena.

Findings

High diffusivity correlates polar field at minimum with next cycle strength.

The model explains regular solar cycle features.

Limited data supports the model's predictive capability.

Abstract

The most promising model for explaining the origin of solar magnetism is the flux transport dynamo model, in which the toroidal field is produced by differential rotation in the tachocline, the poloidal field is produced by the Babcock--Leighton mechanism at the solar surface and the meridional circulation plays a crucial role. After discussing how this model explains the regular periodic features of the solar cycle, we come to the questions of what causes irregularities of solar cycles and whether we can predict future cycles. Only if the diffusivity within the convection zone is sufficiently high, the polar field at the sunspot minimum is correlated with strength of the next cycle. This is in conformity with the limited available observational data.