Ionospheric response to PPEF events in the Indian region during high and low intense geomagnetic storms

Abstract

Space weather variations can significantly affect ionospheric electron density, which can, in turn, adversely affect various navigational and communication technologies. One such phenomenon is the prompt penetration electric field. The convective electric field from a magnetospheric origin penetrates the lower ionosphere during a geomagnetic storm. The electric field penetrating the ionosphere can challenge space-based technologies. Thus, understanding the convectional electric field from higher latitudes to the low-latitudinal region during geomagnetic disturbance is critical. The ionosphere over the Indian region consists of equatorial and low latitude dynamics, such as equatorial ionization anomaly, that are highly dynamic even during the quiet days. Therefore, understanding the effects of prompt penetration electric field observed in the Equatorial Electrojet is of utmost importance over the Indian region. In the current study, two geomagnetic storms, the St. Patrick's Day storm of 17th March 2015 and another low intense storm of 8th June 2014, were chosen to understand the effects of PPEF over equatorial ionization anomaly. The ionospheric density was enhanced during the relatively less intense geomagnetic storm compared to the St. Patrick's Day storm. In these two events, large-scale ionospheric irregularities were observed from ROTI values during the local daytime hours, but no ionospheric scintillation was detected (S4 index).