# Evolution of the Sun's Polar-fields and the Poleward Transport of Remnant Magnetic Flux

## TL;DR

This study analyzes solar magnetic field data to understand the evolution and reversal of the Sun's polar magnetic fields, highlighting the role of remnant flux surges and atypical active regions in multiple polarity reversals.

## Contribution

It provides a detailed analysis of the mechanisms behind polar field reversals, including the impact of non-Joy's and anti-Hale's active regions on magnetic flux transport.

## Key findings

- Multiple polar field reversals observed in Cycles 20 and 21.
- Remnant flux surges of different polarities cause complex reversal patterns.
- Non-Joy's and anti-Hale's active regions influence flux transport and reversals.

## Abstract

Synoptic magnetograms and relevant proxy data were analyzed to study the evolution of the Sun's polar magnetic fields. Time-latitude analysis of large-scale magnetic fields demonstrates cyclic changes in their zonal structure and the polar-field buildup. The time-latitude distributions of the emergent and remnant magnetic flux enable us to examine individual features of recent cycles. The poleward transport of predominantly following polarities contributed much of the polar flux and led to polar-field reversals. Multiple reversals of dominant polarities at the Sun's poles were identified in Cycles 20 and 21. Three-fold reversals were caused by remnant flux surges of following and leading polarities. Time-latitude analysis of solar magnetic fields in Cycles 20--24 revealed zones which are characterized by a predominance of negative (non-Joy's) tilts and appearance of active regions which violate Hale's polarity law. The decay of non-Joy's and anti-Hale's active regions result in remnant flux surges which disturb the usual order in magnetic flux transport and sometimes lead to multiple reversals of polar fields. The analysis of local and large-scale magnetic fields in their causal relation improved our understanding of the Sun's polar field weakening.