Back to Search Start Over

N-S Asymmetry and Solar Cycle Distribution of Superactive Regions from 1976 to 2017

Authors :
Ming-Xian Zhao
Gui-Ming Le
Yong-Hua Liu
Source :
Universe, Vol 8, Iss 11, p 605 (2022)
Publication Year :
2022
Publisher :
MDPI AG, 2022.

Abstract

There were 51 superactive regions (SARs) during solar cycles (SCs) 21–24. We divided the SARs into SARs1, which produced extreme space weather events including ≥X5.0 flares, ground level events (GLEs), and super geomagnetic storms (SGSs, Dst < −250 nT), and SARs2, which did not produce extreme space weather events. The total number of SARs1 and SARs2 are 31 and 20, respectively. The statistical results showed that 35.5%, 64.5%, and 77.4% of the SARs1 appeared in the ascending phase, descending phase, and in the period from two years before to the three years after the solar maximum, respectively, whereas 50%, 50%, and 100% of the SARs2 appeared in the ascending phase, descending phase, and in the period from two years before to the three years after the solar maximum, respectively. The total number of SARs during an SC has a good association with the SC amplitude, implying that an SC with a higher amplitude will have more SARs than that with a lower amplitude. However, the largest flare index of a SAR within an SC has a poor association with the SC amplitude, suggesting that a weak cycle may have a SAR that may produce a series of very strong solar flares. The analysis of the north–south asymmetry of the SARs showed that SARs1 dominated in the southern hemisphere of the sun during SCs 21–24. The SAR2 dominated in the different hemispheres by turns for different SCs. The solar flare activities caused by the SARs with source locations in the southern hemisphere of the sun were much stronger than those caused by the SARs with source locations in the northern hemisphere of the sun during SCs 21–24.

Details

Language :
English
ISSN :
22181997
Volume :
8
Issue :
11
Database :
Directory of Open Access Journals
Journal :
Universe
Publication Type :
Academic Journal
Accession number :
edsdoj.f44c00d4584742f68fe219381326c991
Document Type :
article
Full Text :
https://doi.org/10.3390/universe8110605