## 5 Conclusions  
After careful analysis and discussion of the ten selected cases of SF development coupled with associated topside irregularities, the following key findings were identified:  
1. A strong association was observed between bottomside midlatitude SF occurrences and irregularities in Swarm latitude Ne profiles at the topside ionosphere. FSF or MSF frequently aligned with topside disturbances, as demonstrated in nine cases, while RSF exhibited a weaker connection (Case 8). FSF signatures, as explained by [PERSON] 1991 [3], arise from multiple ray path interactions with shallow isotonic ripples near the zenith, especially under conditions of low Ne fluctuations or elevated F2 layer heights. These bottomside irregularities, influenced by factors like asymmetric geomagnetic field lines, GWs, and MSTIDs, subsequently affect the topside Ne distribution. 2. SF signatures result in significant Ne fluctuations in the Swarm latitude Ne profile, exceeding 0.5 \(\times\) 10\({}^{4}\) elec/cm\({}^{3}\) in the lower midlatitude region (latitude! 45\({}^{\circ}\) N) and 1 \(\times\) 10\({}^{4}\) elec/cm\({}^{3}\) in the upper midlatitude region (latitude! 45\({}^{\circ}\) N). 3. SF-associated MSTIDs significantly influence topside irregularities. A clear link was identified between the propagation direction of oblique ionogram traces and fluctuations in Swarm latitude Ne profiles. However, ST and MRE signatures, due to their limited duration, showed no apparent connection to topside irregularities. 4. Topside irregularities in Swarm Ne profiles were observed in six instances when ROTI fluctuations reached or exceeded 0.15 TECU/min during SF activity, accompanied by hmF2 values greater than 350 km. 5. The geomagnetic storm activity enhances the possibility of collocation between the topside irregularity formations in the presence of SF signatures (Case 10). Conceptualization, H.H. and K.S.P. ; methodology, H.H. and K.S.P. ; validation, K.S.P. ; formal analysis, H.H. and K.S.P. ; investigation, H.H. and K.S.P. ; resources, H.H. and K.S.P. ; data curation, K.S.P. ; writing--original draft preparation, K.S.P. ; writing--review and editing, H.H. and K.S.P. ; visualization, K.S.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. In the present study, we downloaded the ionograms over Juliusruh, Fairford, Dourbes, Pruhonice, Roquetes, and San Vito from 2015 to 2017 from the Digital Ionogram Database or DIDBase (\"[[https://lgdc.uml.edu/common/DIDBFastStationList](https://lgdc.uml.edu/common/DIDBFastStationList)]([https://lgdc.uml.edu/common/DIDBFastStationList](https://lgdc.uml.edu/common/DIDBFastStationList))) (accessed on 16 October 2024)\". The TEC maps (both ROTI and detrended TEC) over Europe were downloaded from the website \"[[https://aer-nc-web.nict.go.jp/GPS/EUROPE/](https://aer-nc-web.nict.go.jp/GPS/EUROPE/)]([https://aer-nc-web.nict.go.jp/GPS/EUROPE/](https://aer-nc-web.nict.go.jp/GPS/EUROPE/)) (accessed on 20 October 2024)\". Swarm data were accessed from \"[[https://vires.services/](https://vires.services/)]([https://vires.services/](https://vires.services/)) (accessed on 18 October 2024)\". All the databases used in the present article are free. We are thankful to Kyoto University, Japan \"([[https://wdc.kugi.kyoto-u.ac.jp/dst_final](https://wdc.kugi.kyoto-u.ac.jp/dst_final)]([https://wdc.kugi.kyoto-u.ac.jp/dst_final](https://wdc.kugi.kyoto-u.ac.jp/dst_final))) (accessed on 19 October 2024)\", for providing the geomagnetic data, and the Solar Influences Data Analysis Center, Royal Observatory of Belgium \"([[https://www.sidc.be/SILSO/datafiles](https://www.sidc.be/SILSO/datafiles)]([https://www.sidc.be/SILSO/datafiles](https://www.sidc.be/SILSO/datafiles))) (accessed on 19 October 2024)\", for providing the daily sunspot number data from 2015 to 2017.