Ionospheric Response to November 5-6, 2023 Geomagnetic Storm over West African Sector

This paper investigates the response of the ionosphere to November 5-6, 2023 geomagnetic storm in West African sectors. The November 5-6, 2023 geomagnetic storm, a significant space weather event, had profound effects on the ionosphere over the West African sector, particularly in countries such as Ghana, Senegal, Benin, Cabo Verde, and Cote d’Ivoire. To investigate the ionospheric response during this storm, the study focused on key parameters such as Total Electron Content (TEC), solar wind conditions, and the horizontal component of Earth’s magnetic field. Using data from GNSS/GPS stations, thermospheric neutral composition measurements, and satellite observations, the analysis reveals marked variations in TEC and other ionospheric parameters, indicating a strong ionospheric response. The analysis of TEC revealed marked variations during the storm, with significant positive ionospheric storm phases observed in countries such as ACRG; Ghana and YKR; Cote d’Ivorie, with TEC values on both November 5 and 6 are significantly higher than the quiet day mean, especially during the early afternoon hours (10:00 UT to 18:00 UT). In contrast, the TEC variations in DAKR; Senegal, CPVG; Cabo Verde and BJC; Benin were less pronounced, suggesting a weaker storm influence in these regions. The relative proximity of these stations to the geomagnetic equator might account for the observed differences, as the equatorial ionosphere is known to respond differently to geomagnetic disturbances compared to higher latitudes. The results highlight the complex interactions between solar wind, geomagnetic activity, and ionospheric conditions in the West African region, providing valuable insights for understanding and predicting ionospheric disturbances. The storm also had a noticeable effect on the thermospheric composition, as indicated by changes in the O/N<sub>2</sub> ratio. The result suggests that the thermosphere experienced a slight relaxation in storm effects by November 6, but with some residual disturbances. Additionally, the prompt penetration electric field model, (PPEFM) effectively captured the behavior of the prompt penetration electric field, PPEF, which intensified or suppressed the prereversal enhancement (PRE) during the postsunset period in the main phase of the March 5-6, 2023, storms.