VARIATIONS OF THE MAGNETIC-FIELDS OF THE SUN AND THE EARTH IN 7-50 DAY PERIODS

The time variations of solar and terrestrial magnetic fields (backgrou nd magnetic field, power of the active regions, AE and aa-indices) hav e been studied. The analysis of these data shows that multiplets of 27 , 13.5, 9 and 7 day periods exist in the solar data as in the terrestr ial data. The solar multiplets 13.5 and 9 days appear predominantly cl ose to the equatorial zone of the Sun and can plausibly be explained b y the presence of active longitudes. The similarity of the variations in period in solar and geophysical data provides evidence that the mag netosphere of the Earth is actually a continuation of the heliosphere. The variations of the terrestrial magnetic field are mainly determine d by the solar background magnetic fields in middle heliographic latit udes.