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.
- Publication:
-
Geomagnetism and Aeronomy
- Pub Date:
- December 2018
- DOI:
- 10.1134/S0016793218080224
- Bibcode:
- 2018Ge&Ae..58.1159A