On the Spectrum of Geomagnetic Variations Accompanying Jerks

Abstract—Based on the data of several spaced magnetic stations, the spectrum of geomagnetic variations is studied in the range of periods from two to 40 years. Special attention is paid to spectral features in the supposed range of action of intraterrestrial processes that cause geomagnetic jerks. It is shown that the detected spectral peak in the vicinity of the period of 6.5 years aligns with the previously revealed recurrence pattern of jerks with a period of three to four years; however, this peak is absent in the spectrum of solar activity. The possible wave mechanisms of the occurrence of jerks and their 6-year quasi-periodicity caused by known types of magnetohydrodynamic waves in the liquid core of the Earth, are considered, and it is shown that they are not sufficiently convincing in reproducing observations of jerks.