Do Solar Eclipses Generate Propagating Ionospheric Perturbations?

Abstract

Plasma depletion during a solar eclipse is well-documented, but the generation of other forms of ionospheric perturbations by the impact of eclipses is controversial. This study aims to evaluate the generation of additional ionospheric perturbations through case studies of total solar eclipses observed across the United States on 21 August 2017 and 8 May 2024. Total electron content (TEC) values are used to track ionospheric perturbations along the eclipse paths. When a smoothing filter (Savitzky–Golay filter) is applied to detect ionospheric perturbations, negative TEC perturbations are observed during totality, while positive TEC perturbations are detected around the beginning and end of the eclipses. These perturbations, caused by rapid TEC variations during these periods, are interpreted as filtering artifacts. Quasi-periodic multiple TEC perturbation layers are detected along the eclipse paths when an oscillatory filter (polynomial detrending) is applied. However, as this filter introduces wave-like artifacts during detrending, the resulting patterns do not represent actual TEC perturbations. Based on our observational and test results, we conclude that eclipse-induced ionospheric perturbations beyond the well-documented plasma depletion are not evident because actual eclipse-induced perturbations are not distinguishable from filtering artifacts.