On the Distinct Periodicities of Sunspot Counts in Flaring and Non-flaring Active Regions

TL;DR

This study analyzes the periodicities of sunspot counts in flaring and non-flaring active regions over two solar cycles, revealing distinct periodic behaviors and complexities that suggest different underlying physical processes.

Contribution

It applies wavelet analysis and wavelet entropy to further characterize the different periodicities and complexities in sunspot counts of flaring and non-flaring regions, expanding prior research.

Findings

Flaring regions show a maximum periodicity of 113 days.

Non-flaring regions exhibit higher periodicities up to 327 days.

Distinct periodicities imply different magneto-hydrodynamic behaviors.

Abstract

In a recent work, Kilcik et al. (2017), have detected the temporal and periodic behavior of sunspot counts (SSC) in flaring (i.e. C, M, or X class flares), and non-flaring active regions for the last two solar cycles, covering the period: 1996 - 2016. The main results obtained are: 1) The temporal behavior of monthly means of daily total SSC in flaring and non-flaring active regions are different and these differences are also varying from cycle to cycle; 2) The periodicities detected in SSC of flaring and non-flaring active regions are quite different and these variations are also different from one cycle to another; the highest detected period in the flaring active regions is 113 days, while there are much higher periodicities (327, 312, and 256 days) in non-flaring regions. The detection of typical different periodicities in flaring and non-flaring regions can suggests both important differences and physical interpretation in the magneto-hydrodynamic behavior of the Sun. For this reason in the present paper we show a further periodicity analysis of the sunspot counts in flaring and in non-flaring active regions using the same data source of that used by the above cited authors and applying a powerful wavelet analysis tool which is particularly useful to detect multiscale features of complex unsteady and unevenly sampled time series. In order to futher support the differences and similarities found in the time behavior of SSC in flaring and non-flaring regions, we also computed the behavior of the wavelet entropy, a proper time function which allow us to measure the degree of complexity in the dynamics of the related time series.