Geomagnetically induced currents (GICs) are a direct consequence of space weather. They are caused primarily by intense and rapidly varying ionospheric currents that can be hazardous to technological systems on the surface of the Earth. Sudden impulse (SI) events caused by the passage of interplanetary shocks have been shown to produce magnetic variations on the ground large and fast enough to cause large GICs. The aim of this project is to develop empirical and physics-based models of the ionospheric portion of the SI current system and use these models to calculate, and ultimately predict, the geomagnetically induced fields at the surface of the Earth. The study will be accomplished by developing an empirical model of the SI currents using measurements from ground-based magnetometers combined with radar measurements of the ionospheric plasma drift. Also, a physics-based model of the SI currents system will be developed using a global magnetospheric model and upstream solar wind measurements to evaluate its ability to represent the current system. The induced magnetic and electric fields from these model current system will be calculated using the numerical techniques known as the method of auxiliary sources, the complex image method, and by utilizing the magnetotelluric equations and a model of the Earth's conductivity. The result of the project will be a predictive model, based on the upstream solar wind conditions, that will forecast the size, location, and duration of geomagnetically induced fields produced by SI events. In addition, techniques that combine magnetometer and radar data will be developed. This research has important scientific relevance becaue large GICs are known to cause severe effects on electric power grids, sometimes resulting in socioeconomic losses that can exceed tens of millions of dollars. The research will involve both undergraduate and graduate students in the engineering and physics departments.
