Fractal properties of active regions

Abstract

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 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.

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

“…This method is very suitable when new magnetic flux emerges in a quiet photosphere, but works more poorly when new flux emerges in a mature active region. However, our multifractal segmentation method [4] provides good results in any case. This is easy to see using NOAA 12192 as an example, since this active region showed very high flare activity in late October 2014.…”

“…A discussion of some methodological questions related to the application of this formalism to the analysis of solar magnetograms can be found in [4,13,14]. The observational data used here are video magnetograms of the Sun presented as a grayscale analog signal (or in digital form), in the form of pixel arrays with equal coordinate steps in a limited region in the plane of the sky.…”

“…New magnetic flux can be identified using series of magnetograms [1], or through characteristic morphological features, such as large gradients in the vicinities of magnetic-field polarity inversion lines. A method for the detection of emerging flux regions based on the multifractal properties of the distribution of the solar magnetic field [2,3] has been developed, which uses multifractal segmented images obtained from maps of the photospheric magnetic field [4]. Testing of the method using data obtained in 2006-2007 and 2009-2010 [4] suggested it was promising.…”

A Fractal Analysis of Magnetograms Within Active Regions

“…Given the suitability of fractals in describing many non-linear geometry in nature, it is therefore a useful tool in its application to the geometry of sunspots and active regions (Deng, 2016;Golovko and Salakhutdinova, 2012) The size distribution of active regions has been shown to demonstrate a power law which implies fractal structures (Harvey and Zwaan, 1993).…”