Great North American Eclipse: A Multi‐Platform Study of Ionospheric and Geomagnetic Disturbances on 8 April 2024

Abstract The Great American Eclipse occurred on 8 April 2024, and traversed across North and Central America, with solar coverage varying from 80% to 100% in various areas. This presented a unique opportunity to explore the interconnected ionosphere‐thermosphere‐magnetosphere system through a synchronized multi‐instrumental methodology. This research delves into the ionospheric and geomagnetic reactions to the eclipse by examining Total Electron Content (TEC) derived from Global Navigation Satellite System (GNSS) data, variations in Very Low Frequency (VLF) signals, satellite observations from the SWARM and COSMIC‐2 missions, and geomagnetic field readings from five INTERMAGNET stations. TEC data from nine GPS stations from the International GNSS Service (IGS) shows a time delay of 11–33 min and a decrease of TEC from 42% to 58%. Longer delays are observed at lower latitudes and stations with less obscuration. The intensity of depletion was found to fluctuate depending on latitude, local time, and the extent of solar obscuration. Additionally, Atmospheric Gravity Waves (AGW) induced by the eclipse were identified in TEC data from various GNSS stations, featuring wave periods ranging from 20 to 80 min, with amplitudes increasing near the path of totality. Dynamic changes in the lower ionosphere were indicated by the significant amplitude and electron density (N e ) changes, with noticeable fluctuations, in the VLF data collected from three transmitters and five receivers located along the eclipse trajectory. Observations from the SWARM and COSMIC‐2 satellites corroborated the ground‐based results, with SWARM‐A identifying a maximum reduction in N e anomaly of 3.6 × 10 5 el/cm 3 , while COSMIC‐2 occultation data revealed notable reductions in N e profiles from D to F regions. Analysis of the geomagnetic field across the five different stations indicated significant aperiodic and quasiperiodic disturbances, especially in the X‐component, which correlated with solar obscuration and disruptions in the ionospheric current system within the dynamo region.