Analyzing Variations of the Earth's Geomagnetic Field During Substorms

This work is a study of Geomagnetically Induced Currents (GICs) during periods of substorm activity. GICs are currents that form due to geomagnetic activity and are an important area of study as they can negatively impact society. Their relationship to substorms is not currently well understood, with most studies focusing on the relationship with geomagnetic storms.

Using the THEMIS ground magnetometer system based in North America, we can analyze variations that are observed within the geomagnetic field measured at the ground, denoted dB/dt. This value provides a useful proxy for the strength of GICs and is easier to measure.

The strength of GICs has a dependence on small-scale variations within the ionospheric currents. These currents are associated with the aurora, so we also use the THEMIS All Sky Imagers (ASIs) to observe the development of the aurora during similar periods. Auroral data is much more readily available than data measuring GICs directly. This allows for an effective, high-resolution alternative which will allow us to better understand the processes that can lead to the formation of large dB/dt. Ultimately, this will enable us to better predict and prepare for periods of large dB/dt in the future.