Behaviour of the ionospheric F2-layer during geomagnetic storms in southern middle latitudes

Abstract

Hourly values of NrnF2 and h'F2 from South American stations were used to study the behavior of the ionosphere during geomagnetic storms. The results show a remarkable increase in NmF2 and h'F2 during perturbed days (by a factor of 2) with respect to the monthly median. It is suggested that the upward drift of plasma is produced by an eastward electric field of magnetospheric origin during the first day of the storm. Thermospheric winds play an important role during the positive phase of the storm.