Intense Geomagnetically Induced Currents (GICs): Association with Solar and Geomagnetic Activities

Abstract

We present a statistical study of the intense geomagnetically induced currents (GICs) in the subauroral region, which can damage ground electronic systems. From the natural gas pipeline recordings taken near Mäntsälä, Finland (geographic: 60.6 ∘N, 25.2 ∘E), 605 GICs with peak intensity > 10 A were registered from 1999 through 2019, ≈ 2 solar cycles. During Solar Cycle 23, the occurrence peak was observed during the solar maximum with fewer events during the descending phase and no events during the solar minimum. Overall a lower occurrence rate was recorded during Solar Cycle 24. There was an asymmetric semi-annual variation of events with a larger number during September–November than during March–April, and the lowest occurrence around the Summer solstice. While only one event was recorded during geomagnetic quiet conditions (SYM-H > − 50 nT), ≈ 2 % of all events were associated with moderate (−50 nT > SYM-H ≥ − 100 nT), ≈ 31 % with intense (−100 nT > SYM-H ≥ − 250 nT), and ≈ 67 % with superintense (SYM-H < − 250 nT) geomagnetic storms. Among these, ≈ 72 % occurred in the storm main phase and ≈ 28 % in the recovery phase. Interplanetary sheaths are found to be the most efficient events causing the majority (≈ 50.8 %) of the GICs with peak intensity > 10 A followed by magnetic clouds (≈ 44.0 %), corotating interaction regions (≈ 3.1 %), fast forward shocks following the sheaths (≈ 1.9 %), and solar wind high-speed streams (≈ 0.2 %). © 2022, The Author(s), under exclusive licence to Springer Nature B.V.