Periodic variation and phase analysis of grouped solar flare with sunspot activity

TL;DR

This study analyzes the periodicities and phase relationships between grouped solar flares and sunspot numbers over several decades, revealing key cycles and phase delays that inform understanding of solar magnetic energy storage.

Contribution

It provides a comprehensive statistical analysis of the periodicities and phase delays between solar flares and sunspots, highlighting their relation to solar cycles and differential rotation.

Findings

Both GSF and SN exhibit periodicities related to solar rotation, QBO, and Schwabe cycle.

The Schwabe cycle signal in GSF lags behind SN by about 7.8 months.

Results suggest magnetic energy storage processes in the solar corona.

Abstract

Studies on the periodic variation and the phase relationship between different solar activity indicators are useful for understanding the long-term evolution of solar activity cycle. Here we report the statistical analysis of grouped solar flare (GSF) and sunspot number (SN) during the time interval from January 1965 to March 2009. We find that, 1) the significant periodicities of both GSF and SN are related to the differential rotation periodicity, the quasi-biennial oscillation (QBO), and the eleven-year Schwabe cycle (ESC), but the specific values are not absolutely identical; 2) the ESC signal of GSF lags behind that of SN with an average of 7.8 months during the considered time interval, implying that the systematic phase delays between GSF and SN originate from the inter-solar-cycle signal. Our results may provide evidence about the storage of magnetic energy in the corona.