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Evolution of solar active regions: Detecting the emergence of new magnetic field through multifractal segmentation  

Aleksey Golovko   Submitted: 2015-10-18 23:58

New emerging magnetic flux is identifed using a multifractal segmentation method used to investigate regularities in the evolution of active regions and activity complexes. The SOLIS, MDI SOHO, and SOT Hinode magnetograms were used. Observations of the active region NOAA 10488 on October 26?28, 2003 indicate considerable variability of areas of newmagnetic flux on a characteristic time scale of 1?2 h. Broadening of the multifractal spectrum in magnetogram sections corresponding to areas of new flux leads to their detection on segmented multifractal images corresponding to the minimal fractal dimensions. New regularities in the emergence of magnetic flux in the 24th solar cycle are studied using data obtained in 2010?2014. A positive correlation of the time variations of areas of new magnetic flux of N and S polarities is predominant at all stages in the development of the cycle. A gradual decrease in the correlation coefficient during 2010?2014 is associated with the progressive complexity of the relationships among active regions, which leads to their clustering into activity complexes.

Authors: A. A. Golovko and I. I. Salakhutdinova
Projects: None

Publication Status: Published in Astronomy Reports, 2015, V. 59, P. 776.
Last Modified: 2015-10-20 12:20
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Fractal Properties of Active Regions  

Aleksey Golovko   Submitted: 2012-06-08 19:56

The dynamics of active regions have been investigated using multi-fractal analysis methods, based on magnetograms of the full solar disk in the 630.2 nm line obtained with the SOLIS vector spectromagnetograph of Kitt Peak Observatory (USA) during 2006?2007 and January 1, 2009?April 12, 2010. The applied method of multi-fractal segmentation reveals the appearance of new magnetic fluxes on the Sun disk. A comparison of these fluxes with flare activity shows that the flares are generated in areas of interaction of emerging fluxes with existing structures.

Authors: A. A. Golovko and I. I. Salakhutdinova
Projects: None

Publication Status: Astronomy Reports, 'Online First' on SpringerLink
Last Modified: 2012-06-10 17:20
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The variations of the scaling parameters of the structure functions in solar active regions at the pre-flare stage  

Aleksey Golovko   Submitted: 2005-05-22 18:34

A series of subflares in active region NOAA 9077 (July 2000) and in the activity complex NOAA 0039 + NOAA 0050 were investigated. The structure functions and their characteristics for sets of images of active regions in the hydrogen α line (Hα ) were calculated. The ranges of the spatial scales of different scaling behavior of the structure functions were revealed. The existence of intermittent turbulence (multi-fractal structure) in active regions of the chromosphere is shown. Peculiarities of the scaling parameters variations of the structure functions at pre-flare stage are investigated. It was found that on average 20 min before a subflare onset considerable deviation of these variations from the mean occurs, which may be of importance for predictions. It was discovered that maximum variations of scaling parameters with an accuracy to 15 min (on average), in a number of cases coincide with variations of the elongated chromospheric structures in an active-region area. We used Hα filtergrams obtained with the chromospheric telescope of the Baikal observatory operated by ISTP SD RAS. The telescope is coupled with a Halle birefringent filter with a 0.05 nm bandpass, and a Princeton Instruments 2048 × 2048 pixel CCD camera with 16-bit amplitude resolution.

Authors: Irina I. Salakhutdinova and Aleksey A. Golovko
Projects: None

Publication Status: Solar Physics (2004), V. 225, PP. 59-74
Last Modified: 2005-05-22 18:34
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Evolution of solar active regions: Detecting the emergence of new magnetic field through multifractal segmentation
Fractal Properties of Active Regions
The variations of the scaling parameters of the structure functions in solar active regions at the pre-flare stage

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