Sign singularity and flares in solar active region NOAA 11158

TL;DR

This study analyzes the sign singularity and spectral properties of current structures in solar active region NOAA 11158, linking small-scale magnetic complexity to large flare eruptions.

Contribution

It introduces a novel analysis of sign-singular measures and spectral scaling in solar active regions, connecting small-scale magnetic features to flare activity.

Findings

Sudden changes in cancellation exponents coincide with large flares

Presence of two distinct spectral scaling ranges

Correlation between small-scale current properties and flare eruptions

Abstract

Solar Active Region NOAA 11158 has hosted a number of strong flares, including one X2.2 event. The complexity of current density and current helicity are studied through cancellation analysis of their sign-singular measure, which features power-law scaling. Spectral analysis is also performed, revealing the presence of two separate scaling ranges with different spectral index. The time evolution of parameters is discussed. Sudden changes of the cancellation exponents at the time of large flares, and the presence of correlation with EUV and X-ray flux, suggest that eruption of large flares can be linked to the small scale properties of the current structures.