Investigation of the negative ionospheric response of the 8 September 2017 geomagnetic storm over the European sector

In this study, we investigate the negative ionospheric response over European sector during two storms that took place on 8 September 2017, primarily, by exploiting observations ten locations. The spatial and temporal variations of TEC, foF2 hmF2 characteristics are examined with aim to explain physical mechanisms underlying strong response. We detected very sharp electron density (in terms TEC) decrease main phases attributed phenomenon large displacement Midlatitude Ionospheric Trough (MIT). Our study also revealed show different features caused processes. addition, Large Scale Traveling Disturbances (LSTIDs) were observed both storms, followed enhanced Spread F conditions Digisonde stations. regional dependence storm effects was demonstrated, as behavior northern part Europe differed from southern part.