Evolution of an Emerging Anti-Hale Region and its Associated Eruptive Solar Flares in NOAA AR 12882
Abstract
Solar active regions that violate the Hale-Nicholson rule are rare, but once formed, they tend to be flare-productive. In this letter, we investigated the evolution of an anti-Hale region newly emerging from the active region AR 12882 with a regular Hale distribution. The entire active region became very active, producing two eruptive flares within 48 hr after the emergence of the anti-Hale region. Strong photospheric shear motions appeared in this anti-Hale region, changing its tilt angle from the north-south direction to the east-west direction. The flux emergence and shearing motions continuously injected magnetic energy and negative magnetic helicity into the upper atmosphere. Meanwhile, the upper coronal structure changed from double J-shaped to reverse S-shaped, forming a magnetic flux rope lying above the anti-Hale region. This magnetic flux rope erupted successfully, then re-formed and erupted successfully again, producing a C2.7 flare and an M1.6 flare, respectively. Moreover, a large cusp structure was observed to form next to the flaring region after the M1.6 flare. Accordingly, we conclude that the evolution of the emerging anti-Hale region provides sufficient magnetic energy and helicity for the flares, and the interaction between the emerging anti-Hale region and the preexisting Hale active region eventually promotes the flares to be eruptive.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2022
- DOI:
- 10.3847/2041-8213/ac8fef
- Bibcode:
- 2022ApJ...937L..11X
- Keywords:
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- Solar active regions;
- Solar flares;
- Solar activity;
- Solar coronal mass ejections;
- 1974;
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