This paper presents large scale changes to the ionosphere that were observed over a large portion of the continental US from 200 – 450 km altitude during the April 2024 solar eclipse. We observed a decrease in electron density of 50 %, a drop in electron and ion temperatures of 40 % and 20 % respectively. Unique features included lower densities and temperatures north of the eclipse path as compared to the south, and ion temperature decrease along a narrow region parallel to the eclipse path.

Gravity waves are well known for deforming the bottom-side plasma of the F region into the wavelike ionization structures which then act as a seed for Rayleigh–Taylor instability, which in turn generates irregularities. The present study features midnight fossil airglow depletions that revived due to ongoing gravity wave (GW) activity and turned into an active depletion.