# Polar Cap Patches Scaling Properties: Insights from Swarm Data
## 4 Discussion and Conclusions
Therefore, the analysis carried out in this study has revealed that the electron density fluctuations within the PCPs, identified using a Swarm Level 2 product, exhibit scale characteristics that differ from those found by analyzing the same fluctuations outside these irregularities. In general, PCPs are characterized by higher values of both scaling exponents and RODI. These differences are accentuated with the intensification of geomagnetic activity and are mainly concentrated in the cusp and in the region of separation between the two convective cells. It is worth noting that PCPs form in an ionospheric environment that differs significantly from the one where plasma bubbles develop, while the scale properties of electron density fluctuations inside plasma bubbles are completely different from the surrounding environment, with a second-order scaling exponent value of (\(0.98\pm 0.21\)) inside the bubbles and around 2 in the surrounding area [19]. The RODI values are also markedly different, increasing by over one order of magnitude inside the bubbles [19; 21]. Conversely, the scaling properties inside (including PCPs' borders) and outside PCPs are similar indicating a state of widespread turbulence in the ionospheric region under investigation, which is absent in the equatorial ionospheric region. During GPS LoL events recorded by the Swarm constellation, a notable difference in scaling properties and higher values of RODI compared to the surrounding environment were observed in the plasma density irregularities [21]. To gain a deeper understanding of the impact of PCPs on GPS signal propagation, we conducted an analysis to assess how the irregularities at the base of LoL events are attributable to PCPs. Our findings reveal that a significant percentage of LoL events occurring over 74\({}^{\circ}\) of QD-latitude coincided with PCPs. This was the case for over half of the events (\(\sim\)55%) in the Northern hemisphere and approximately one third (\(\sim\)33%) in the Southern hemisphere. The coincidence actually increases to approximately 57.4% in the Northern hemisphere and 45.7% in the Southern hemisphere during periods when AE > 300 nT. The difference between the two hemispheres could be ascribed to the varying occurrence of PCPs. Interestingly, despite a lower occurrence of PCPs, the number of LoLs is higher in the Southern hemisphere [24]. Overall, PCPs are confirmed as ionospheric irregularities that actively contribute to the loss of electromagnetic signals propagating through the ionosphere. However, a complete overlap between the presence of these irregularities and the occurrence of LoLs is not observed. The comparison of joint distributions between RODI and \(\gamma(2)\) for ionospheric irregularities associated with PCPs and LoL events (Figure 12) highlights that only PCPs with significantly high RODI values have the potential to trigger a LoL event. Conceptualization, R.T. and P.D.M. ; methodology, G.C. ; formal analysis, R.T. and G.L. ; investigation, R.T. and G.L. ; data curation, R.T., G.C. and A.P. ; writing--original draft preparation, R.T., P.D.M. and G.L. ; writing--review and editing, all authors; project administration, P.D.M. All authors have read and agreed to the published version of the manuscript. This research received financial support from the Italian PNRA under contract PNRA18_002 89-A \"Space weather in Polar Ionosphere: the Role of Turbulence\". Swarm data can be accessed at [[http://swarm-disse.eo.esa.int](http://swarm-disse.eo.esa.int)]([http://swarm-disse.eo.esa.int](http://swarm-disse.eo.esa.int)) (accessed on 31 August 2023). AE index is freely available at [[https://wdc.kugi.kyoto-u.ac.jp/ae_provisional/index.html](https://wdc.kugi.kyoto-u.ac.jp/ae_provisional/index.html)]([https://wdc.kugi.kyoto-u.ac.jp/ae_provisional/index.html](https://wdc.kugi.kyoto-u.ac.jp/ae_provisional/index.html)) (accessed on 31 August 2023). The results presented rely on data collected by ESA-Swarm mission. We thank the European Space Agency that supports the Swarm mission.