太阳物理研究组知识库

Utilized here is the Carte Synoptique solar filament archive, namely the catalogue of solar filaments from March 1919 to December 1989, corresponding to solar rotation numbers 876 to 1823 to study latitudinal migration of solar activity at high latitudes. Except the well-known poleward migration of solar activity from middle latitudes to the poles, an equatorward migration is found from the solar poles toward middle latitudes (about 40 degrees) within a normal cycle, which is neglected before, and the time interval for the former migration (4.4 years) is about 2.2 years shorter than that for the latter (6.6 years), indicating that the change from one migration to the other takes place around the maximum time of a normal cycle. In the future, a dynamo model should represent the migration from the poles toward middle latitudes of the Sun, besides the migration in "butterfly diagrams" and the "rush to the poles". The traditional extended activity cycle is actually a part of the period of the successive migration from the poles toward the solar equator.