Solar-cycle and Latitude Variations in the Internetwork Magnetism

TL;DR

This study reveals clear latitude and solar cycle variations in quiet-Sun internetwork magnetism, challenging the notion that local dynamo action is the sole source of such magnetism.

Contribution

It provides evidence of cyclic and latitudinal variations in quiet-Sun magnetism, indicating multiple origins beyond local dynamo processes.

Findings

Magnetic fields increase toward the solar poles.

Long-term variations are observed at the disk center and poles.

Variations are almost anticorrelated between these regions.

Abstract

The importance of the quiet-Sun magnetism is that it is always there to a greater or lesser extent, being a constant provider of energy, independently of the solar cycle phase. The open questions about the quiet-Sun magnetism include those related to its origin. Most people claim that the local dynamo action is the mechanism that causes it. This fact would imply that the quiet-Sun magnetism is nearly the same at any location over the solar surface and at any time. Many works claim that the quiet Sun does not have any variation at all, although a few of them raise doubt on this claim and find mild evidence of a cyclic variation in the the quiet-Sun magnetism. In this work, we detect clear variations in the internetwork magnetism both with latitude and solar cycle. In terms of latitude, we find an increase in the averaged magnetic fields toward the solar poles. We also find long-term variations in the averaged magnetic field at the disk center and solar poles, and both variations are almost anticorrelated. These findings do not support the idea that the local dynamo action is the unique factory of the quiet-Sun magnetism.