Thayer Research Group

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Geospace Electrodynamics

Earth’s electric system consists of a quasi-static global electric circuit, transient current sources, diverse conductive channels, and a variety of charge distributions that involve many different regions across the Sun-Earth system. This diversity in discipline and scales makes the electric system a frontier research problem for Earth system studies. In fact, the Earth’s electric system can be considered the ultimate link between solar, galactic, ionospheric and magnetospheric processes and lower atmosphere processes, cloud system dynamics, and climate evolution.

Schematic of processes relevant to the GEC, extending from Earth's surface to the upper atmosphere (>100 km), geospace and beyond.  Thunderclouds and other electrified clouds serve as generators of current (orange arrows) and maintain the earth-ionosphere leaky "capacitor" at a potential Vi with respect to the ground.  Currents return in the fair weather regions (blue arrows).  Magnetic field lines can serve to electrically connect the Northern and Southern Hemispheres.  Modification of electrical resistivity by ionizing solar energetic protons and galactic cosmic rays are two ways in which the solar system modulates the GEC; a third is through coupling with the magnetosphere.  Magnetic fluxes due to auroral currents (green arrows) produce "geomagnetically-induced currents (GIC)" in the ground.


NSF Frontiers in Earth System Dynamics (FESD) program supports CU-led project to study the Electrical Connections and Consequences Within the Earth System - what has been called the Global Electric Circuit (GEC) Project - see link to the project website