Postdoctoral Fellowship: OPP-PRF: Investigating Polar Geomagnetic Signatures Associated with Substorm Onset to Address Data Gaps in Southern Hemisphere Space Weather Research

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Space is often considered a vacuum, but it is home of various electromagnetic fields and charged particles called plasma. Variations in these fields and plasma can be called “space weather”, and these space weather events may severely impact various human-deployed technological networks in several ways, including interfering with GPS technologies and causing vast electric power blackouts. Geomagnetic substorms in polar regions are daily space weather events and these are typically identified and studied using Auroral Electrojet (AE) indices, which are compiled using ground-based geomagnetic field variation measurements. However, while AE indices exist in the Northern Hemisphere, there are no such indices developed for the Southern Hemisphere. There simply is not enough land to have appropriately placed and spaced geomagnetic instruments. However, this is important because there are interhemispheric asymmetries between the northern and southern polar regions. In other words, the two hemispheres are not identical, so it cannot be assumed that substorm observations from the northern auroral zone are compatible with research done in the southern polar areas. As the interhemispheric asymmetries in substorm research are also not often able to be evaluated, this award will be addressing the southern polar regions’ data gap by investigating potential alternate methods to identify southern polar substorms. The Pi1B waves are a type of natural Ultra Low Frequency (ULF) waves characterized by broadband bursts in the Pi1 range (1 – 40 second periods). Substorm onsets are well correlated with Pi1B waves in the evening to post-midnight sectors, and it was suggested in the geospace literature that Pi1B waves could be used to monitor polar substorms development. This award will use a mix of existing, publicly available ground-based magnetometer data and in-situ satellite measurements to identify and compare both the substorm onsets and Pi1B waves. This research will address the following outstanding science questions: (1) Are Pi1B waves a proxy for Auroral Electrojet intensification associated with substorm onset; (2) If so, how does the Pi1B proxy compare with existing proxies based on the AE and other geomagnetic indices; and (3) What are physical mechanisms that can explain connections between the Pi1B waves and substorm onsets.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.