A Fractal Analysis of Magnetograms within Active Regions

Brandon Rajkumar, Shirin Haque

Published 2019-11-09Version 1

The magnetograms of sixteen Active Regions, observed during June - November 2015, were obtained from the Joint Science Operations Center and used to determine the fractal dimensions of various magnetic field groups. The fields were divided into strong (positive and negative) and weak (positive and negative) groupings. The area-perimeter method was used to determine the fractal dimensions for the umbral and penumbral regions of the magnetograms. The fractal dimensions were found to be 1.79 \pm 0.49 and 1.96 \pm 0.29 for strong and weak magnetic fields respectively. When compared to the umbral and penumbral fractal dimensions determined by (Rajkumar, Haque and Hrudey, 2017) using white light images, an inverse relationship was found, with the umbra showing lower fractal dimensions than the penumbra for the magnetic field groups compared to the intensity images. This directly implies that there is greater complexity in the penumbral magnetic field groupings than the umbral region. This has implications for models that constrain how the magnetic field groups are contained in the cooler umbral regions.