Solar-Terrestrial relationships at solar cycle minimum

In this paper we present the results of the analysis of geomagnetic field measurements conducted from May 31 to June 14, 2007, around the summer solstice during the current solar activity minimum phase. Such campaign of measurements was conducted in the framework of the Italian initiatives for the International Heliophysical Year. During the whole period, the geomagnetic field does not show any development of storms due to the absence of a persistent interplanetary magnetic field southward component.We focused our attention on the moderate geomagnetic pulsation activity in the Pc5 (1.6-6.6 mHz) and Pc3 (22-100 mHz) frequency range. Pc5 pulsations were mainly observed in correspondence to the solar wind pressure variations which characterize the interaction regions between the corotating streams occurring in the period. The analysis suggests a solar wind driving of pulsations. On the other hand, the observed Pc3 pulsations seem to be related to the penetration in the magnetosphere of upstream waves.