Abstract
Magnetic field structures on the solar atmosphere are not symmetric distribution in the northern and southern hemispheres, which is an important aspect of quasi-cyclical evolution of magnetic activity indicators that are related to solar dynamo theories. Three standard analysis techniques are applied to analyze the hemispheric coupling (north-south asymmetry and phase asynchrony) of monthly averaged values of solar Hα flare activity over the past 49 years (from 1966 January to 2014 December). The prominent results are as follows: (1) from a global point of view, solar Hα flare activity on both hemispheres are strongly correlated with each other, but the northern hemisphere precedes the southern one with a phase shift of 7 months; (2) the long-range persistence indeed exists in solar Hα flare activity, but the dynamical complexities in the two hemispheres are not identical; (3) the prominent periodicities of Hα flare activity are 17 years full-disk activity cycle and 11 years Schwabe solar cycle, but the short- and mid-term periodicities cannot determined by monthly time series; (4) by comparing the non-parametric rescaling behavior on a point-by-point basis, the hemispheric asynchrony of solar Hα flare activity are estimated to be ranging from several months to tens of months with an average value of 8.7 months. The analysis results could promote our knowledge on the long-range persistence, the quasi-periodic variation, and the hemispheric asynchrony of solar Hα flare activity on both hemispheres, and possibly provide valuable information for the hemispheric interrelation of solar magnetic activity.
Highlights
Solar flares are the violently expulsive phenomena in the Sun
The long-term variations of solar magnetic structures driven by the magnetic field evolution have been monitored systematically, and there is a statistical imbalance in the occurrence of magnetic activity indicators on both hemispheres when averaged over a certain time scale ranging from a year to a solar cycle (Yan et al, 2008; Xie et al, 2012; Ouyang et al, 2017)
The results derived by the R/S analysis strongly support the idea that solar magnetic indicators exhibit long-range persistence, but the dynamical complexity in the two hemispheres are not identical
Summary
Solar flares are the violently expulsive phenomena in the Sun. They are observed in a wide range of wavelengths from decameter radio waves to gamma-rays beyond 1 GeV (Yan et al, 2015). The long-term variations of solar magnetic structures driven by the magnetic field evolution have been monitored systematically, and there is a statistical imbalance in the occurrence of magnetic activity indicators on both hemispheres when averaged over a certain time scale ranging from a year to a solar cycle (Yan et al, 2008; Xie et al, 2012; Ouyang et al, 2017) This phenomenon is known as the north-south asymmetry of solar activity, and the existence of the hemispheric asymmetry in different solar activity indicators observed in the solar atmosphere is well known.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
