Geomagnetically induced currents - physics, applications and extreme events

Substantial progress has been made over the past decade or so in understanding the geomagnetically induced currents (GIC) phenomenon impacting long conductor systems on the ground. Much of this progress has been enabled by data from ground magnetometer arrays. In this paper I briefly review the current status of our understanding of the physics of GIC and novel applications enabled by the new understanding. More specifically, I will demonstrate how we can follow the chain of physical processes from the solar corona down to the upper mantle of the Earth and to GIC. Further, I will show how state-of-the-art models enable predictive modeling of the entire chain of complex processes. The potential for severe societal consequences has been driving recent increasing interest in extreme GIC events. I will show how we have addressed the issue by generating 100-year GIC event scenarios. These scenarios that are based mostly on data from ground magnetometer arrays are of substantial power grid industry inteterest and have been fed directly into further engineering analyses. The engineering analyses estimate GIC impact on high-voltage power transmission systems of interest. The goal of our extreme GIC work is to provide realistic quantification of the risk associated with extreme GIC. I will review the initial results of generation of 100-year geomagnetically induced current scenarios.