## 5 Conclusions  
In this paper, the ionospheric response is studied by analyzing \(f\)oF2 variation at Darwin, Townsville, and Canberra stations in the Australian region during the six intense geomagnetic storms (\(-\)100 nT \(\leq Dst\geq-\)200 nT) that occurred during 2012. The main results of the investigation are concluded as:  
* Positive and negative storm effects (ionospheric storms) in \(f\)oF2 were observed during five out of six intense storms at both low and mid-latitudes stations. The storms of which the main phase occurred in the local daytime showed only positive ionospheric storms during their main phases associated with eastward PPEFs which strengthened the equatorial plasma fountain by enhancing the \(\mathbf{E}\times\mathbf{B}\) vertical plasma drifts;
* The recovery phase of the storms showed both positive and negative ionospheric storms with the predominant occurrence of negative ionospheric storms which were stronger and of long duration as compared to positive ionospheric storms;
* Long duration decreases in \(f\)oF2 (negative ionospheric storms) during the recovery phase of storms are related DDEFs and overshielding electric field which changed the normal ionospheric \(\mathbf{E}\times\mathbf{B}\) drifts and to the equatorward motion of storm-time thermospheric neutral winds with decreased O/N\({}_{2}\) density ratio.  
Further work on long-term data analysis over the varying longitudinally located stations in the low- to mid-latitude region is required for a better understanding of the F\({}_{2}\)-region response to the geomagnetic storms.  
**Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/atmos13030480/s1](https://www.mdpi.com/article/10.3390/atmos13030480/s1)]([https://www.mdpi.com/article/10.3390/atmos13030480/s1](https://www.mdpi.com/article/10.3390/atmos13030480/s1)), Figure S1: The IMF \(B_{Z}\) variations during the magnetic storms given in Table 1.  
**Author Contributions:** Conceptualization, S.K. and E.A.K.; methodology, S.K. and E.A.K.; resources, E.A.K. and S.K.; formal analysis, E.A.K.; writing--original draft, E.A.K. and S.K.; writing--review and editing, S.K.; visualization, S.K. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research received no external funding.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Not applicable.  
**Acknowledgments:** The _foF2_ data were obtained from the World Data Centre, Bureau of Meteorology, Australia (online at [[http://www.sws.bom.gov.au/World_Data_Centre](http://www.sws.bom.gov.au/World_Data_Centre)]([http://www.sws.bom.gov.au/World_Data_Centre](http://www.sws.bom.gov.au/World_Data_Centre)), accessed on 22 December 2021). The _Dst_ index data were obtained from the World Data Centre, Kyoto University, Kyoto, Japan (online at [[http://www.ssde.u-kigi-kyoto-ac.jp](http://www.ssde.u-kigi-kyoto-ac.jp)]([http://www.ssde.u-kigi-kyoto-ac.jp](http://www.ssde.u-kigi-kyoto-ac.jp)), accessed on 22 December 2021).  
**Conflicts of Interest:** The authors declare no conflict of interest.