Near-surface Azimuthal Magnetic Fields and Solar Activity Cycles

TL;DR

This paper investigates the near-surface azimuthal magnetic fields of the Sun across multiple activity cycles, revealing their structure, hemispheric differences, and potential role in solar activity, proposing an alternative magnetic field generation scheme.

Contribution

It introduces a new analysis of azimuthal magnetic fields using limb observations and proposes a novel magnetic field generation mechanism differing from Babcock-Leighton models.

Findings

Azimuthal magnetic fields are observed at various latitudes and change sign with cycles.

Hemispheric differences in magnetic field directions are identified.

A new scheme for magnetic field generation is proposed.

Abstract

Variations of the azimuthal magnetic fields of the Sun in the 23-25 activity cycles of the activity cycles are considered. To identify azimuthal magnetic fields, the analysis of daily observations of LOS magnetic fields from the regions near the solar limb was performed. It is shown that with a sufficiently large averaging of the data, large-scale structures are distinguished that can be interpreted by horizontal magnetic fields directed along the East-West line. Azimuthal magnetic fields are visible both in the low-latitude zone and at high latitudes. Azimuthal fields at the same latitudes have opposite directions in the northern and southern hemispheres, and also change sign in even and odd cycles of activity. The mechanism of formation of global azimuthal magnetic fields and their role in the cycle of solar activity is discussed. The near-surface azimuthal magnetic field is closely related to the activity cycle. Apparently, the azimuthal field is formed from U-shaped flux tubes of active regions (AR). Due to the presence of the tilt angle AR during differential rotation, the subsurface magnetic fields are pulled in the azimuthal direction. The role of azimuthal magnetic fields in solar activity cycles is considered. A scheme for generating a magnetic field according to a scheme different from Babcock-Leighton dynamo models is proposed.