Cycle Variations in the Photospheric and Interplanetary Magnetic Field and Solar Wind Parameters

Abstract

The influence of cycle changes in the polar and nonpolar photospheric magnetic fields on variations in the interplanetary magnetic field (IMF) and the solar wind parameters in solar cycles 21–24 are analyzed. The results show that variations in the polar and nonpolar magnetic fields on the Carrington-rotation scales determine the parameters of the IMF and the solar wind, respectively, with the dominance of the zonal and sector structures of the global magnetic field of the Sun. The solar wind parameters exhibit a decrease in the maximum values from cycle to cycle when the sector structures dominate, while the minimum values decrease when the zonal structures dominate. This reflects a general lowing of magnitudes of both nonpolar and polar magnetic fields of the Sun observed over the last cycles. It is demonstrated that the importance of accounting for the effect of cyclic variations of the polar magnetic field on the IMF and solar wind parameters is currently underestimated.