Large-scale solar cycle features of solar photospheric magnetic field

TL;DR

This study analyzes solar magnetic field data across latitudes to identify cycle features and phase relationships, providing constraints for solar dynamo models.

Contribution

It offers new observational constraints on solar cycle phases in different latitudinal zones using synoptic chart data.

Findings

Polar region flux correlates with total magnetic flux 5 years earlier.

High-latitude flux peaks lag sunspot cycle by 3 years.

Low-latitude flux peaks shift forward at 32.2 days per degree.

Abstract

It is well accepted that the solar cycle originates from a magnetohydrodynamics dynamo deep inside the Sun. Many dynamo models have long been proposed based on a lot of observational constraints. In this paper, using 342 NSO/Kitt Peak solar synoptic charts we study the solar cycle phases in different solar latitudinal zones to set further constraints. Our results can be summarized as follows. (1) The variability of solar polar regions' area has a correlation with total unsigned magnetic flux in advance of 5 years. (2) The high-latitude region mainly appears unipolar in the whole solar cycle and its flux peak time lags sunspot cycle for 3 years. (3) For the activity belt, it is not surprised that its phase be the same as sunspot's. (4) The flux peak time of the low-latitude region shifts forward with an average gradient of 32.2 $day/deg$. These typical characteristics may provide some hints for constructing an actual solar dynamo.