Analyzing the Effects of Geomagnetic Storms on the F2-region Ionosphere in South Pacific Region

The geomagnetic storm effects on the F2-region ionospheric parameters namely, foF2 (critical frequency of the F2-region), and h'F (virtual height of the F-region) in the South Pacific region are studied in this research. The storms were selected based on their intensity measured by the Dst-index. The moderate storms are within −50 nT Dst > −250 nT and super storms within Dst ≤ −250 nT. Two moderate, two intense and two super geomagnetic storms were selected for this study where, foF2 and h'F data were analysed before the storm, during the storm and after the storm at selected equatorial and low latitude stations in the South Pacific Region. The variations in the foF2 and h'F parameters for the F2-region were mainly due to prompt penetration electric fields (PPEFs) and disturbance dynamo electric fields (DDEFs). The decrease in the foF2 during sudden storm commencement and the main phase onset of the storm was mainly due to PPEFs effect which lasts for few hours and later the DDEFs are main drivers for the negative and positive ionospheric trends in the recovery phase of the storm. The geomagnetic storms used in this study and the ionosonde stations in the South Pacific region were never studied before, hence, this study will be useful for the wider scientific communities and all the organizations or people who use ionosphere for communications, report space weather and satellite applications. The constant monitoring of ionosphere before, during and after the geomagnetic storms will help all the forementioned organizations and communities