The regression coefficients of the time-weighted AL index (AL_w) to the Dst index are calculated for each year from 1966 to 1994. It is found that the slope of the linear regression equation varies over a period of 11 years: The coefficient a_1 in a regression equation, Dst = a_0 + a_1 AL_w, is maximized near the sunspot maximum and is minimized near the sunspot minimum. The long-term variations in the relationship between these indices and solar wind parameters are also examined. The dependence of Dst on the solar wind electric flux, B_zV~2, is nearly constant, while the values of AL for fixed values of B_zV~2 are greater at the solar minimum than at the solar maximum, where B_z and V denote the Z component of the interplanetary magnetic field and the solar wind speed, respectively. Possible causes that can account for these characteristics are discussed.
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