Geomagnetically Induced Currents from the Sun to the Power Grid

Jennifer L. Gannon, Andrei Swidinsky, Zhonghua Xu, Jennifer L. Gannon, Andrei Swidinsky, Zhonghua Xu

• Publisher: American Geophysical Union
• Year: 2019
• Print ISBN: 9781119434344
• eBook ISBN: 9781119434382
• Edition: 1
• Topic: Ciencias físicas
• Subtopic: Geología y ciencias de la Tierra

An introduction to geomagnetic storms and the hazards they pose at the Earth's surface

Geomagnetic storms are a type of space weather event that can create Geomagnetically Induced Currents (GICs) which, once they reach Earth's surface, can interfere with power grids and transport infrastructure. Understanding the characteristics and impacts of GICs requires scientific insights from solar physics, magnetospheric physics, aeronomy, and ionospheric physics, as well as geophysics and power engineering.

Geomagnetically Induced Currents from the Sun to the Power Grid is a practical introduction for researchers and practitioners that provides tools and techniques from across these disciplines.

Volume highlights include:

• Analysis of causes of geomagnetic storms that create GICs
• Data and methods used to analyze and forecast GIC hazard
• GIC impacts on the infrastructure of the bulk power system
• Analysis techniques used in different areas of GIC research
• New methods to validate and predict GICs in transmission systems

Part I
Space Weather

1
An Introduction to Geomagnetically Induced Currents

Chigomezyo M. Ngwira^1,2,3 and Antti A. Pulkkinen²

¹ Department of Physics, The Catholic University of America, Washington, DC, USA

² Goddard Space Flight Center, Space Weather Laboratory, National Aeronautics and Space Administration, Greenbelt, MD, USA

³ Now at Atmospheric and Space Technology Research Associates, Louisville, CO, USA

ABSTRACT

Earth‐directed space weather is a serious concern that is recognized as one of the top priority problems in today’s society. Space weather‐driven geomagnetically induced currents (GICs) can disrupt operation of extended electrically conducting technological systems. This threat to strategic technological assets, like power grids, oil and gas pipelines, and communication networks, has rekindled interest in extreme space weather. To improve national preparedness, it is critical that we understand the physical processes related to extreme events in order to address key national and international objectives. This paper serves to provide a basic introduction to space weather and GICs, and highlights some of the major science challenges the GIC community continues to face.

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Key Points

• Geomagnetically induced currents (GICs) is a space weather‐driven phenomena.
• It is a threat to strategic technological assets, such as power grids, oil and gas pipelines, and communication networks.
• This paper serves to provide basic introduction on space weather and GICs, and the major science challenges the GIC community continues to face.

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1.1. INTRODUCTION

Space weather is a serious natural threat to national security, and is recognized as one of the top priority problems today. The term “space weather” generally refers to dynamic conditions on the Sun, in the solar wind, and in the near‐Earth space environment that can influence the performance of man‐made technology, and can also affect human health and activities. Space weather is a multi‐faceted phenomenon, thus the scientific community is faced with a challenge to better understand this natural hazard in order to enhance preparedness.

Geomagnetically induced currents (GICs), a space weather‐driven phenomena, have received increased international policy, science, industry, and public interest. GICs flowing on ground‐based electrically conducting systems can disrupt operation of critical infrastructure such as power grids, pipelines, telecommunication cables, and railway systems (e.g., Barlow, 1849; Davidson, 1940; Boteler and Jansen van Beek, 1999; Molinski et al., 2000; Pirjola, 2000; Pulkkinen et al., 2001; Eroshenko et al., 2010, and references therein). The majority of community efforts focus on extreme forms of space weather which not only have severe impact on our technology and human space travel, but also challenge our understanding of the space weather phenomena.

Scientific investigations are critical for understanding the basic physics and predicting the potential impact of extreme space weather. Public opinions on the topic of extreme space weather include wide ranging views. This chapter provides a high‐level summary of space weather and GICs. While some of the topics touched on cover a broad range of space weather domains, the discussions are oriented/biased towards the geophysical facet of GICs. For more insight on specific GIC aspects, the reader is urged to consult other sections of this volume.

1.2. THE SPACE WEATHER CHAIN

The Sun is the primary source of all space weather in the heliosphere. Sudden, violent eruptions of solar material from the Sun’s atmosphere (the corona) called coronal mass ejections (CMEs), mark the beginning of major space weather events that eventually produce geomagnetic storms (disturbances) in the Earth’s upper atmosphere. The Sun’s activity is closely governed by the solar activity cycle, which has an average length of about 11 years. The cycle is defined by the number of visible active sunspots on the solar surface.

During solar maximum period when solar activity is high, the Sun can launch multiple CMEs towards Earth per day. A CME can be perceived as a cloud of plasma with the solar magnetic field known as the interplanetary magnetic field (IMF) embedded within it. Upon arriving at Earth, CMEs interact with the magnetosphere, a low‐density partially ionized region around the upper atmosphere dominated by Earth’s magnetic field. This interaction then triggers geomagnetic disturbances (GMDs) that lead to violent global magnetic field variations.

Orientation of the IMF varies with time and is important for interaction between the solar wind and the magnetosphere. Historically, the most intense disturbances have been recorded when the IMF Bz component, which is parallel to the solar rotation axis is oppositely directed to the Earth’s magnetic field, a condition often referred to as a southward or negative IMF. Under southward condition, the coupling between the solar wind and the magnetosphere is enhanced and the transfer of CME plasma, momentum, and e...

Table of contents

• Cover
• Table of Contents
• CONTRIBUTORS
• PREFACE
• Part I: Space Weather
• Part II: Geomagnetic Induction
• Part III: Power System Impacts
• Index
• End User License Agreement