Amplitude-modulated Pc2-3 pulsations

Amplitude-modulated Pc2 and Pc3 pulsations observed at Korets in the Ukraine during 1959, a year of high solar activity, and 1964, a year of low solar activity, are compared. The patterns of modulated Pc2 and Pc3 pulsations over the period of 1959 to 1974 are examined with attention to the intensity of background short-period pulsations. Duration of the modulated Pc pulsations are correlated with the extent of solar activity.