Time path of turbulence and multi-fractality of magnetic field in the evolution of an active region

TL;DR

This study analyzes the evolution of turbulence and multifractality in the photospheric magnetic field of an active solar region, revealing that these properties evolve smoothly and are linked to overall magnetic complexity rather than individual flares.

Contribution

It provides a detailed analysis of the time evolution of turbulence and multifractality in solar active regions, highlighting their independence from flare timing and their relation to magnetic complexity.

Findings

Turbulence and multifractality do not show abrupt changes before or after flares.

These properties evolve smoothly, reflecting the magnetic complexity of the active region.

Photospheric turbulence evolves independently from the highly intermittent corona.

Abstract

Magnetograms acquired with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) were used to calculate and analyze time variations of turbulence and multifractality in the photosphere during the development and flaring of a mature active region NOAA 13354 during its passage across the solar disk. Turbulence was explored with 2D magnetic power spectra from magnetograms, and multifractality was analyzed using the structure functions of magnetograms. Time variations of the magnetic power spectrum exponent $\alpha$ and of the multifractalty exponent $\kappa$ demonstrate no pre-flare or post-flare abrupt peculiarities, instead, long periods of stability with smooth transitions into other conditions were observed. A conclusion was inferred that the turbulence and multifractality time path in the photospheric magnetic field does not follow the timing of single flares, however, it tends to correspond to the levels of the magneto-morphological complexity and flaring productivity of an AR. So, in the sense of self-organized criticality (SOC), the photosphere, being in the state of self-organization, evolves independently from the highly intermittent, SOC-state corona.