Sign singularity and flares in solar active region NOAA 11158

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.

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Cited by in corpus (7)

• The Vertical Current Approximation Nonlinear Force-Free Field Code - Description, Performance Tests, and Measurements of Magnetic Energies Dissipated in Solar Flares
• Anomalous scaling in magnetohydrodynamic turbulence: Effects of anisotropy and compressibility in the kinematic approximation
• Sign singularity of the local energy transfer in space plasma turbulence
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• Divergent Horizontal Sub-surface Flows within Active Region 11158
• Cancellation exponents in isotropic turbulence and magnetohydrodynamic turbulence
• Photospheric Magnetic Free Energy Density of Solar Active Regions