Ionospheric Total Electron Content Perturbations Driven by Magnetospheric Ultra Low Frequency Waves: Case Study of the 27-30 May 2017 Geomagnetic Storm

Perturbations in ionospheric Total Electron Content (TEC) with timescales of between 10 seconds and 1000 seconds can be driven from above by processes in the magnetosphere – including magnetospheric Ultra Low Frequency (ULF) waves – and below by processes such as acoustic- gravity waves in the atmosphere. Characterizing the subset of TEC perturbations related to ULF waves is of high priority as several studies have shown these perturbations impact ionospheric space weather. However, it is currently unknown whether ULF waves routinely drive TEC perturbations of significance for space weather. We present preliminary results of the TEC perturbations driven by ULF waves during the 27 – 30 May 2017 geomagnetic storm. In this work, we analyze multiple types of ground-based and space-borne observational data of the ionosphere and magnetosphere, including the Global Navigation Satellite System (GNSS)-derived TEC data, ground magnetometer data, GOES satellite data, and SuperDARN radar data. We identify perturbations in the TEC data collected over the North American sector and associated them with observed magnetospheric ULF waves. To investigate the relation between characteristics of the TEC perturbations and characteristics of the ULF waves, we conduct Global Ionosphere-Thermosphere Model (GITM) simulations driven by idealized ULF waves via the recently developed High-latitude Input for Meso-scale Electrodynamics (HIME) framework. Our work provides insight on the dynamic coupling processes between the magnetosphere and the ionosphere and contributes to the source identification of TEC perturbations.