# Correlation Study of Auroral Currents with External Parameters During 10-12 October 2024 Superstorm
## 4 Discussion
### Correlation Analysis
On the nightside, upward FACs are most strongly correlated with Dst, and downward FACs are most strongly correlated with Vsw. Previous research showed that the equatorward extension of dayside FACs was primarily influenced by IMF Bz, while the latitudinal variation in nightside FACs was more closely related to Dst during the Halloween storm in 2003 [5]. Note that [PERSON] et al. (2006) [5] did not distinguish FAC polarity. This finding largely aligns with our results for upward FACs on both the southern dayside and nightside. [PERSON] et al. (2024) [10] also found that the latitudes of peak FACs were most strongly correlated with Pd and Dst during the May 2024 storm, while the correlation with Em was not particularly dominant. However, during this October 2024 storm, Em is the main correlated factor for the MLat of FACs on the dawnside-duskside. On the dayside of the Northern Hemisphere, Pd is the dominant factor, while on the nightside, Em again plays the dominant role. The comparison with the May storm suggests that the dayside FAC MLat is primarily correlated with Pd, and the nightside FAC MLat is mainly correlated with Em or Pd during geomagnetic storms, which should be a relatively common result. However, it further suggests that the correlation factors of the position of dawnside-duskside FAC MLat vary depending on the specific geomagnetic storm event. In summary, during geomagnetic storms, the peak values and latitudes of FACs may be correlated with different factors depending on the local time and hemisphere, which also helps explain why the timing of their peaks and lowest latitudes differ. Figure 6 presents the Spearman correlation study between PEJ peak values in the auroral oval of two hemispheres and seven solar wind and geomagnetic parameters across four local time sectors. At northern dawn and dusk and northern and southern nighttime, Em shows the largest correlation with the PEJ peak values. At southern dusk (dawn), the PEJ peak value is most strongly correlated with Nsw (Dst). On the dayside, the PEJ peak in the Northern Hemisphere is most strongly correlated with Vsw, while in the Southern Hemisphere, it is most strongly correlated with Pd. Unlike the May 2024 geomagnetic storm, where the PEJ peak density was primarily correlated with Dst [10], the PEJ peak density during this October storm was largely correlated with Em and Pd. Figure 5: The Spearman correlation study between the MLat of the peak FACs and seven external parameters. (**a,c**) Northern Hemisphere (NH) and (**b,d**) Southern Hemisphere (SH). Different colors denote different local times. Brown and yellow are for duskside upward (J+) and downward FACs (J\(-\), (**a,b**)) and for daytime upward and downward FACs (**c**), (**d**), respectively. Green and blue are for dawnside upward and downward FACs (**a,b**) and for nighttime upward and downward FACs (**c**), (**d**), respectively. The strongest correlation coefficients are further indicated by half gray bars. Figure 7 shows the correlation coefficients between the latitudes of PEJ peaks in the auroral oval and seven solar wind and geomagnetic parameters. The northern PEJ latitude at dawn-dusk is best correlated with Pd, while the southern PEJ MLat is most strongly correlated with Dst. In the Northern Hemisphere, the PEJ latitude on the dayside is most strongly correlated with Dst, while on the nightside, it is most strongly correlated with Vsw. The southern PEJ MLat on the dayside is most strongly correlated with IMF Bz, while on the nightside, it is most strongly correlated with Em. [PERSON] et al. (2024) found that the latitudes of PEJ peaks across most local time sectors tend to show strong correlations with Pd and Dst, which is consistent with the results of this study. Thus, by comparing PEJ during the magnetic storm events in May and October, the following conclusions can be drawn: the correlation factors of PEJ intensity vary between different magnetic storm events.