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ORIGINAL RESEARCH article

Front. Astron. Space Sci.
Sec. Space Physics
Volume 11 - 2024 | doi: 10.3389/fspas.2024.1392697
This article is part of the Research Topic Space weather: Magnetosphere Ionosphere Thermosphere (M-I-T) Coupling View all 5 articles

First direct observations of interplanetary shock impact angle effects on actual geomagnetically induced currents: The case of the Finnish natural gas pipeline system

Provisionally accepted
  • 1 University of Maryland, Baltimore County, Baltimore, United States
  • 2 NASA Goddard Space Flight Center, Greenbelt, Maryland, United States
  • 3 University of Colorado Boulder, Boulder, Colorado, United States

The final, formatted version of the article will be published soon.

    The impact of interplanetary (IP) shocks on the Earth's magnetosphere can greatly disturb the geomagnetic field and electric currents in the magnetosphere-ionosphere system. At high latitudes, the current systems most affected by the shocks are the auroral electrojet currents.These currents then generate ground geomagnetically induced currents (GICs) that couple with and are highly detrimental to ground artificial conductors including power transmission lines, oil/gas pipelines, railways, and submarine cables. Recent research has shown that the shock impact angle, the angle the shock normal vector performs with the Sun-Earth line, plays a major role in controlling the subsequent geomagnetic activity. More specifically, due to more symmetric magnetospheric compressions, nearly frontal shocks are usually more geoeffective than highly inclined shocks. In this study, we utilize a subset (332 events) of a shock list with more than 600 events to investigate, for the first time, shock impact angle effects on the subsequent GICs right after shock impact (compression effects) and several minutes after shock impact (substorm-like effects). We use GIC recordings from the Finnish natural gas pipeline performed near the M änts äl ä compression station in southern Finland. We find that GIC peaks (> 5 A) occurring after shock impacts are mostly caused by nearly frontal shocks and occur in the postnoon/dusk magnetic local time sector. These GIC peaks are presumably triggered by partial ring current intensifications in the dusk sector. On the other hand, more intense GIC peaks (> 20 A) generally occur several minutes after shock impacts and are located around the magnetic 1Shock-induced GICs at M änts äl ä midnight terminator. These GIC peaks are most likely caused by intense energetic particle injections from the magnetotail which frequently occur during substorms. The results of this work are relevant to studies aiming at predicting GICs following solar wind driving under different levels of asymmetric solar wind forcing.

    Keywords: interplanetary shocks, shock geometry, Geomagnetic activity, geospace response, ionospheric response, Geomagnetically induced currents

    Received: 27 Feb 2024; Accepted: 07 May 2024.

    Copyright: © 2024 Oliveira, Zesta and Vidal-Luengo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Denny Oliveira, University of Maryland, Baltimore County, Baltimore, United States

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