Fractal properties of active region and flare

Abstract

A fractal analysis of narrowband images of the chromosphere and transition layer has been performed in order to study regimes of turbulence and their variations during time-varying processes in active regions. The NOAA 10039 and 10050 activity complexes on July 31, 2002, were observed at Baikal astrophysical observatory of ISZF SO RAN in the H-α line using a chromospheric telescope equipped with a Halle birefringent filter (BF) with a passband of 0.5 A. Images of the same activity complexes in the spectral band centered at the FeXI 171 A line, obtained at TRACE space observatory, have been processed using the same technique. The method of structure functions has been used to compute the time series of the scaling parameters. The power spectra of two-dimensional images have been used to compute the time variations in the fractal dimension of the considered activity complex. It has been indicated that the parameters of a multifractal structure (intermittent turbulence) demonstrate jump-like and quasiperiodic time variations correlating with flares. These variations were detected in the H-α and FeXI 171 A lines of the transition zone, using the ground-based and onboard measurements, which demonstrates that they are of the solar origin.