Asymmetric Distribution of the Solar Photospheric Magnetic Field Values

TL;DR

This study analyzes the asymmetric distribution of solar photospheric magnetic field values, revealing Lorentzian behavior, periodicities related to solar cycles, and determining polar field reversal times for cycles 23 and 24.

Contribution

It demonstrates that Lorentzian functions better describe magnetic field distributions and links asymmetry features to small-scale magnetic fields and solar axis inclination.

Findings

Lorentzian fits better than Gaussian for magnetic field distribution

Identified two periodicities related to solar B0 angle and cycle

Reversal times for polar fields in cycles 23 and 24 are determined

Abstract

Understanding the characteristics of the solar magnetic field is essential for interpreting solar activities and dynamo. In this research, we investigated the asymmetric distribution of the solar photospheric magnetic field values, using synoptic charts constructed from space-borne high-resolution magnetograms. It is demonstrated that the Lorentzian function describes the distribution of magnetic field values in the synoptic charts much better than the Gaussian function, and this should reflect the gradual decay process from strong to weak magnetic fields. The asymmetry values are calculated under several circumstances, and the results generally show two periodicities related to the variation of the solar B$_0$ angle and the solar cycle, respectively. We argue that it is the small-scale magnetic fields, the inclination of the solar axis, the emergence and evolution of magnetic flux, and the polar fields that are responsible for the features of asymmetry values. We further determined the polar field reversal time of solar cycles 23 and 24 with the flip of asymmetry values. Specifically, for cycle 24, we assert that the polar polarities of both hemispheres reversed at the same time - in March 2014; as to cycle 23, the reversal time of the S-hemisphere is March 2001, while the determination of the N-hemisphere is hampered by missing data.