Delta spots and great flares
Abstract
Using eighteen years of observations at Big Bear, we summarize the development of δ spots and the great flares they produce. We find δ groups to develop in three ways: eruption of a single complex active region formed below the surface, eruption of large satellite spots near (particularly in front of) a large older spot, or collision of spots of opposite polarity from different dipoles. Our sample of twenty-one δ spots shows that once they lock together, they never separate, although rarely an umbra is ejected. The δ spots are already disposed to their final form when they emerge. The driving force for the shear is spot motion, either flux emergence or the forward motion of p spots in an inverted magnetic configuration.
- Publication:
-
Solar Physics
- Pub Date:
- January 1987
- DOI:
- 10.1007/BF00147707
- Bibcode:
- 1987SoPh..113..267Z
- Keywords:
-
- Solar Flares;
- Solar Physics;
- Sunspots;
- H Alpha Line;
- Magnetohydrodynamic Turbulence;
- Spatial Resolution;
- Solar Physics;
- Flare;
- Fibril;
- Active Region;
- Opposite Polarity;
- Forward Motion