Geomagnetic storm effects on ionospheric total electron content at Toro, Nigeria

Abstract

Energy input into the upper atmosphere during geomagnetic storms takes the form of 
enhanced electric fields, currents, and energetic particle precipitation. This storm-time 
energy input affects the ionosphere–thermosphere coupling which leads to the balance 
between the storm-induced circulation and the regular circulation and determines the 
spatial distribution of negative and positive storm effects. This study revealed episodes of 
positive and negative ionospheric storm effects during these storm events with positive 
effects dominating the main phases at the Toro, Nigeria International Global Navigation 
System Satellites Service network station while the recovery period is characterized by 
either positive or negative effects or a combination of both. The geomagnetic storm time 
was determined using the geomagnetic Dst index, southward interplanetary magnetic 
field, and auroral electrojet index. The development of the positive ionospheric storm 
effect at the low latitudes is caused by the upward movement of ionization to regions of 
reduced recombination rate.