ИСТИНА

We present the first results of the analysis of temporal and spatial variability of geomagnetic and telluric electric fields in the eastern Fennoscandia. These variations are compared with available geomagnetically induced current (GIC) measurement in electric power transmission lines. We calculated “synthetic” telluric fields from the IMAGE geomagnetic records via the impedance relationship. The information on impedance tensors is provided by the electromagnetic array BEAR for a deep sounding. The elaborated algorithm synthesizes the telluric E-field from geomagnetic field variations, using the complex impedance tensor. We analyze geomagnetic and E-field variations at several sites for different space weather events: magnetic storm, substorm, and Pi3 pulsations. We analyze induced telluric field dependence on the local geoelecrical structure for several sites with contrasting geoelectric parameters in Eastern Fennoscandian Shield. The modelling results have been compared with observations of the system to monitor GIC in electric power transmission lines deployed at Kola Peninsula and Karelia. We compared the spectral content of geomagnetic, telluric, and GIC variations. This comparison showed that the commonly used time derivative of geomagnetic field dB/dt cannot be used as an effective measure of GIC disturbance. Работа поддержана грантом РНФ № 16-17-00121