Brown, Jo-AnneConnors, MartinReiter, Kyle Wallace2023-06-282023-06-282023-06Reiter, K. W. (2023). Auroral zone geomagnetic activity and space weather implications (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.https://hdl.handle.net/1880/116674Geomagnetic variability in the auroral zone ionosphere has long been a subject of research interest, both for the large dynamic electrical currents that couple it to the magnetosphere, and the space weather impacts of these currents. Our understanding and modeling capacity for translating geomagnetic field variations into power network impacts has greatly expanded over the last several decades. This thesis makes several contributions to our understanding of this system. I develop a novel technique for quantifying and modeling the temporal and spatial variations in geomagnetic fields during substorms at auroral latitudes using principal component analysis. The nature of the spatial variations in ionospheric current drivers of geomagnetic and geoelectric fields are important for predicting the magnitude and extent of geomagnetically induced currents (GICs) in technological systems. Vertical geomagnetic fluctuations are often neglected in geoelectric field modeling for calculating GIC hazards. I demonstrate the coincidence of large impulsive vertical geomagnetic field variations with harmonic distortion in the Hydro-Québec network, an indicator of the presence of GICs in a power transmission network. I develop a finite-difference time-domain electromagnetic modeling technique that can incorporate vertical geomagnetic field variations and apply it to eastern Canada. Using this model, I show the importance of lateral conductivity gradients in turning and intensifying horizontal geoelectric fields along these gradients. I also show that GICs appear to be driven by vertical geomagnetic field fluctuations during a case study, using GIC modeling of the Hydro-Québec power transmission network. This thesis emphasizes the importance of understanding and incorporating spatial variations in ionospheric currents in assessing space weather impacts on auroral zone technological infrastructure and shows the need to include vertical geomagnetic variations in auroral zone geoelectric field modeling.enUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.Space PhysicsPhysicsGeomagnetically Induced CurrentsFDTDElectricity and MagnetismStatisticsGeophysicsdoctoral thesis