Pulsations with the period of 16Osup(m) in the Earth magnetosphere possibly caused by oscillations of the Sun

The measurements of the amplitudes envelope of the geomagnetic micropulsations of Pc 3, 4 obtained at the Borok/ Geophysical Observatory were analyzed by cosinor method to search for magnetospheric pulsations with the period about 160sup(m). The data for 216 days of observations compiled in 1974-1978 were used. It has been found that Pc 3, 4 amplitudes are modulated by the period 160sup(m).01 with the stable phase. The maximum of Pc 3, 4 amplitudes follows that of solar expansion velocity in approximately 20sup(m) (for the center of the disk) according to optical observations. This modulation of Pc 3, 4 amplitudes could be probably caused by the presence of oscillating component in solar UV-radiation over the range lambda 100 nm. The amplitude of the UV flux variation may be as large as 2-4%