Contributions from Different-Type Active Regions Into the Total Solar Unsigned Magnetic Flux

Abstract

Data set acquired by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) during 2010–2017 allowed us to classify active regions (ARs) into three categories: A-type— regular bipolar ARs; U-type—unipolar spots; B-type—irregular ARs, violating either Hale polarity law or Joy’s law or having the leading spot less than the main following spot. A separate subset of anti-Hale ARs was formed. We selected 1494 ARs in total and found the following: (i) Pearson correlation coefficient r between the total unsigned flux for a given category and the International Sunspot Number smoothly decreases with transition from A-type (r = 0.57) to B-type (r = 0.53) to anti-Hale ARs (r = 0.31) to U-type (r = 0.18); (ii) yearly contributions into the total flux from categories also gradually decreases: from 50–70% from A-type ARs to 20–40% from B‑type ARs to 10–20% from U-type ARs to 5–11% from anti-Hale ARs. (iii) At the beginning of the solar minimum, the fraction of flux from anti-Hale groups increased from 5 to 9% and amount of flux per magnetogram was constant at about 10²¹ Mx level. The data are compatible with a concept that generation of the magnetic field on the Sun occurs as a united process in a non-linear dynamical dissipative system, i.e., global and local (fluctuation) dynamos are inseparable and operate together. The observed enhancement of the anti-Hale flux during the solar maximum can be due to the combined mechanisms of global mean-field and local fluctuation dynamos.