On the Role of Physical Processes in Controlling Equatorial Plasma
Bubble Morphology
María Paula Natali
Laboratorio de Meteorología espacial, Atmósfera terrestre, Geodesia, Geodinámica, diseño de Instrumental y Astrometría (MAGGIA), Facultad de Ciencias Astronómicas y Geofísicas (FCAG), Universidad Nacional de La Plata (UNLP), CONICET
Author ProfileAbstract
In this study, we present the results of an analysis of the
morphological features of Equatorial Plasma Bubbles (EPBs) over South
America. In this context, we analyzed data from the Disturbance
Ionosphere indeX (DIX) maps calculated using around 450 Global
Navigation Satellite System (GNSS) stations. To mitigate the influence
of magnetic disturbances on bubble development, only data from
geomagnetically quiet days were utilized. This study covered the period
from the post-peak of solar cycle 24 (2015) to the pre-peak of solar
cycle 25 (2023), totaling 1321 nights with EPB occurrences, representing
the largest dataset of EPBs ever compiled for South America. Our
analysis unveiled several key findings regarding EPBs and their behavior
over the South American region. Firstly, we observed that the amplitude
of plasma depletions and the EPB latitudinal development follow an
approximately 11-year cycle driven by solar radiation levels.
Furthermore, our analysis highlights the significant influence of
factors such as vertical plasma drift velocity during the pre-reversal
enhancement (PRE), longitudinal variations associated with magnetic
declination, as well as the saturation behavior of EPB development with
extreme solar flux. Finally, we outline an empirical model to calculate
the maximum latitudinal extent of EPBs based on solar flux and magnetic
declination as an attempt to provide insights for anticipating EPB
behavior across different solar cycle stages and in different longitude
sectors.