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

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.

16 pages, 5 figures

References in corpus (10)

• The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches
• 25 Years of Self-Organized Criticality: Solar and Astrophysics
• Driving major solar flares and eruptions: a review
• Intermittency Spectra of the Magnetic Field in Solar Active Regions
• 25 Years of Self-Organized Criticality: Numerical Detection Methods
• On the Origin of a Sunquake during the 29 March 2014 X1 Flare
• Signature of the turbulent component of solar dynamo on active region scales and its association with flaring activity
• Distributed Electric Currents in Solar Active Regions
• On the possibility to probe the flare productivity of an active region on the early stage of emergence
• Correlation Functions of Photospheric Magnetic Fields in Solar Active Regions