Torsional oscillation pattern in the large : scale magnetic field (1910-1993) and in the solar corona (1940-1993)
Faculty of Sciences. Physics
Synoptic solar physics
18th National-Solar-Observatory/Sacramento-Peak Summer Workshop on, Synoptic Solar Physics, SEP 08-12, 1997, SUNSPOT, NM
, p. 65-73
University of Antwerp
Differential rotation of the corona in the lines Fe XIV 5303 Angstrom, Fe X 6374 Angstrom and of the large-scale magnetic fields during 1910 - 1993 was studied. It was shown that bands of slower-than-average rotation arise after polar magnetic field reversals and migrate to the equator during 7 - 15 years along the butterfly diagrams of polar faculae and sunspots. The fastest latitude drift of the bands was observed from 1935 to 1955 and it preceded the maximum activity in the 19-th cycle (1955-1965). Latitude span of the bands of torsional oscillations varies from 0.5R. to 1.3 R. and shows a long-term variation of about 55 years. The reasons of occurrence of the rotation bands and their link with the coronal holes in the global solar pattern are discussed.