Об амплитудно-частотных характеристиках геомагнитного шума в диапазоне низких частот

The article presents spectral distribution of the magnetic noise of low frequency (0.01÷200 Hz) within a large industrial city as in the case of Ekaterinburgin in a different time of the day. It is shown that in addition to the power frequency and its first harmonics, the amplitude of the magnetic noise at frequencies less than 3 Hz monotonically increases. Pulses of magnetic fields have the highest amplitude generated by rail and electric vehicles (up to 10.000 nT peak to peak above the metro line), which are significantly higher than the average intensity of the magnetic noise of the city, but this magnetic noise is close to the underground lines and to the railway tracks. Since the duration and frequency of occurrence of the pulsed noise has random nature, they do not appear in the Fourier spectrum as discrete spectral lines.