Day‐to‐day variability in the development of plasma bubbles associated with geomagnetic disturbances

The development of equatorial ionospheric irregularities into large-scale ionospheric plasma bubbles continues to be an active area for scientific investigations. In this paper, we present simultaneous OI 630.0-nm emission all-sky imaging observations carried out at the Astrophysics National Laboratory (LNA), Brazopolis (22.5 degrees S, 45.6 degrees W, altitude 1860 m) and ionospheric sounding observations carried out at Palmas (10.2 degrees S, 48.2 degrees W; located close to the magnetic equator) and Sao Jose dos Campos (23.2 degrees S, 45.9 degrees W; located under the southern crest of equatorial ionospheric anomaly, close to Brazopolis), Brazil, to study the day-to-day variability in the development of ionospheric plasma bubbles during both geomagnetically disturbed and quiet periods in September-October 2002. Also, we present simultaneous complementary phase fluctuation (ROT) data obtained from the global position system (GPS) meridional chain operated by the Brazilian Institute of Geography and Statistic (IBGE). On the three nights studied in the present investigation (one geomagnetically quiet and two geomagnetically disturbed), it has been observed that the geomagnetic disturbances, during this spring equinox period, have a strong effect on the generation and development of ionospheric plasma bubbles.