Geomagnetically induced currents: Science, engineering, and applications readiness

Abstract

This paper is the primary deliverable of the very first NASA Living With a Star Institute Working Group, Geomagnetically Induced Currents (GIC) Working Group. The paper provides a broad overview of the current status and future challenges pertaining to the science, engineering, and applications of the GIC problem. Science is understood here as the basic space and Earth sciences research that allows improved understanding and physics‐based modeling of the physical processes behind GIC. Engineering, in turn, is understood here as the “impact” aspect of GIC. Applications are understood as the models, tools, and activities that can provide actionable information to entities such as power systems operators for mitigating the effects of GIC and government agencies for managing any potential consequences from GIC impact to critical infrastructure. Applications can be considered the ultimate goal of our GIC work. In assessing the status of the field, we quantify the readiness of various applications in the mitigation context. We use the Applications Readiness Level (ARL) concept to carry out the quantification.

The Great Storm of May 1921: An Exemplar of a Dangerous Space Weather Event

“…The great geomagnetic storm of May 1921 produced extreme geophysical conditions, in particular large geoelectric fields (~10 V/km) in several parts of the world. Such large fields are a major concern today because of their potential to impact contemporary technologies such the transmission of electrical power (Pulkkinen et al, ), railway track circuits (Krausmann et al, ), and cathodic protection systems for pipelines (Gummow, ). The May 1921 storm therefore provides a well‐documented historical example that can inform future decisions on the risk that space weather poses to such systems, taking account of how regional differences in the value and complexity of ground conductivity may decrease or increase the risk.…”

Storm and Substorm Causes and Effects at Midlatitude Location for the St. Patrick's 2013 and 2015 Events

“…The derivative of the geomagnetic field, DER‐H, shows also strong disturbances at those timing when UPC‐H signal is also stronger, indicating an association with substorm activity. The derivative of the geomagnetic field is usually a good proxy for GICs, and consequently for disruption of technology (Boteler & Pirjola, ; Pulkkinen et al, ; Trichtchenko & Boteler, ; Viljanen et al, ). This has important consequences for space weather purposes, as these local and strong changes of the geomagnetic field have occurred at midlatitude locations and are associated with substorm activity, something unusual and unexpected at these locations.…”

Recommendations for Next‐Generation Ground Magnetic Perturbation Validation

“…This definition was chosen to investigate the horizontal field fluctuations (i.e., components tangent to the Earth's surface), which are associated with GIC hazards (Pulkkinen et al, ; Viljanen et al, ). A simple forward‐difference method was used to obtain derivatives; this simple approximation is adequate for the given time resolution (Tóth et al, ).…”

“…The value of interest is d B /d t , or the rate of change of the magnetic field as measured on the Earth's surface. This value is especially relevant to geomagnetically induced currents (GICs), which are currents driven through long, ground‐based conductors during geomagnetically active periods (Pirjola, ; Pulkkinen et al, ).…”