Pre-storm NmF2 enhancements at middle latitudes: delusion or reality?
A critical analysis of recent publications devoted to the NmF2 pre-storm enhancements is performed.There are no convincing arguments that the observed cases of NmF2 enhancements at middle and sub-auroral latitudes bear a relation to the following magnetic storms.In all cases considered the NmF2 pre-storm enhancements were due to previous geomagneti