Morphological Study of Plasma Bubbles Using All-Sky Airglow Images and Numerical Simulations: Brazilian Sector

Abstract

This study meticulously examines the morphology of ionospheric plasma depletions, or bubbles, using OI 630 nm airglow all-sky images captured over three Brazilian observatories: Santarém, Bom Jesus da lapa, and Cariri. The analysis focuses on key morphological parameters: zonal distance between adjacent bubbles (Xd), base width of the bubbles (Xw), and branch separation in bifurcated bubbles (Xr). Santarém, the newest equatorial observatory, revealed consistent, periodic depletion aligned with the magnetic meridian, with a peak of 17 bubbles observed in a single night. Conversely, Cariri and Bom Jesus da Lapla exhibited more complex structures, including bifurcations and ramifications. A statistical analysis of 60 nights revealed that Xd ranged from 69 to 214 km, Xw from 24 to 67 km, and Xr from 98 to 269 km. Notably, the zonal distance (Xd), linked to the perturbation seed wavelength (λ) in the equatorial F region, showed no dependence on solar flux. However, both Xw versus Xd and Xr versus Xw displayed strong linear correlation exceeding 80%. To further investigate these findings, a novel three-dimensional bubble model SUPIM/PBM3D, was developed. The theoretical results from this model showed good agreement with the observed airglow morphology, validating the empirical findings and providing a deeper understanding of the processes governing plasma bubble formation and evolution.