The human impact on the Pc1 wave activity

This paper deals with the problem of human impact on the electromagnetic environment of the Earth. We have focused our attention on the Pc1 electromagnetic waves (the frequency range is 0.2-5 Hz), which are spontaneously excited due to the instability of magnetospheric plasma. This paper describes the analysis of the long-term ground-based Pc1 observations to search for the so-called weekend effect, or, more generally, a specific weekly cycle in the Pc1 wave activity. It is supposed that such effects are evident of human origin. The data on the Pc1 occurrence at Borok (Φ=54.05°, Λ=119.44°, L=2.9) in 1958-1992 are examined. The synchronous detection method in the form of superposition epoch analysis has been used. It was found statistically that there is an inherent difference of about 10% in the numbers of Pc1 wave trains between weekdays and weekends. The main conclusion is that the weekly cycle in the Pc1 wave activity is a real geophysical phenomenon.