Evolution of latitude zonal structure of the large-scale magnetic field in solar cycles

Abstract

The latitude zonal component of the large-scale solar magnetic field is analyzed using H-alpha charts for the 1905-1982 period, and the poleward migration of prominences is used to calculate the time of reversal of the polar magnetic field for the 1970-1982 period. It is found that in each hemisphere, the polar, middle latitude, and equatorial zones of the predominant polarity of the large-scale magnetic field can be detected by determining the average latitude of prominence samples referred to one boundary of the large-scale magnetic field. Such prominence samples do not have any regular equatorward drift, and they manifest a poleward migration with a variable velocity of up to 30 m/s, depending on the phase of the cycle.