Study of Geoelectrical Responses to Space Weather Anomalies: Auroral Latitudes, Yenisei-Khatanga Regional Trough.

Abstract—The paper presents the results of analysis of the geoelectric (telluric) field variability during the Earth's magnetic field disturbances, caused by extreme space weather events. The area of the study is the territory of the Yenisei-Khatanga Regional Trough (YKRT) situated in the auroral zone, where geomagnetic disturbances are characterized by a high level of intensity. The economic development of the YKRT as a large oil and gas-bearing area in the Russian Arctic increases the relevance of the study of possible negative impacts of space weather on future infrastructure facilities. The most serious threat to conductive industrial structures in the polar region will be posed by geomagnetically induced currents (GIC) driven by geoelectrical responses to rapid geomagnetic field changes. The analysis of the variability of telluric fields and calculations of their extreme values in the YKRT area were made using a unique magnetotelluric impedance tensor database collected by Nord West Ltd. as a result of the regional phase of the geophysical study of the trough and adjacent areas. The geoelectric field spatial-frequency distributions on the Earth's surface were calculated on the basis of the impedance estimates and harmonic approximations of the external geomagnetic excitation. The obtained maps were correlated with geological data to find areas characterized by maximal distortions of the telluric field. Extreme amplitudes of geoelectrical responses at a series of representative locations in the YKRT were evaluated on the time series of telluric field variations, synthesized through the impedance dependences on frequency and magnetic field time series recorded during geomagnetic storms and substorms at the nearest stationary monitoring sites. The resulting estimates of amplitudes and directions of geoelectric fields during space weather disturbances can be used to account for possible destructive effects of GIC in design of pipelines, power transmission lines and railways. [ABSTRACT FROM AUTHOR]