Studies on a very flare-active δ group: Peculiar δ spot evolution and inferred subsurface magnetic rope structure

摘要: The complex subsurface magnetic rope structure of a very flare-active isolated δ group (McMath 13043, July 1974) is studied by means high-resolution evolutionary data from BBSO and velocity data. This showed unusually fast evolution accompanied number intense flares occurring on the neutral line spot, provided an excellent opportunity to study inherent relation flare occurrence changes configuration. We first examine abnormal this started formation large, compact, reversed spot squeezing multipoles. configuration was deformed penetration into opposite polarity umbra its subsequent disappearance, decaying rapid shear motions. Strong transverse fields over 4000 G were detected in penumbrae some umbral components. Combining these with August 1972 region, groups shown decompose two flare-associated elementary modes: (A) shearing produced growth (B) reduction as spots disappear. propose model emerging twisted knot explain modes apply realistically present evolution. inferred topological region consists tightly (sheet-like) knots long-winding internally loop hooked bottom struture. Their consecutive emergences are suggested 5 group. result indicates that origin concentrated activity may be traced internal responsible for forming anomalous ropes.