# Correlation Study of Auroral Currents with External Parameters During 10-12 October 2024 Superstorm
## 1 Introduction  
A fast-moving coronal mass ejection (CME), observed leaving the Sun on 9 October 2024, triggered a geomagnetic storm that began at 15:22 UT on 10 October. This storm ranks among the most intense since the Halloween storms of 2003, alongside the event on 10 May 2024. A recent study has identified a direct connection between this storm and the orbital decay of Starlink satellites [1]. Notably, the sharp altitude drop of the Starlink-1089 (SL1089) satellite coincided with the onset of the storm's main phase. Although SL1089 was initially scheduled for reentry on 22 October, it reentered 10 days earlier, on 12 October. Aurora was visible in several northern mid-latitude regions, including New York, England, France, and Daqing in Heilongjiang Province, China--an event considered rare for these locations ([[https://www.space.com/spectacular-auroras-photos-thrill-skywatchers-from-geomagnetic-storm-october-2024](https://www.space.com/spectacular-auroras-photos-thrill-skywatchers-from-geomagnetic-storm-october-2024)]([https://www.space.com/spectacular-auroras-photos-thrill-skywatchers-from-geomagnetic-storm-october-2024](https://www.space.com/spectacular-auroras-photos-thrill-skywatchers-from-geomagnetic-storm-october-2024)), accessed on 11 October 2024, [[http://en.people.cn/n3/2024/1011/c90000-20228406.html](http://en.people.cn/n3/2024/1011/c90000-20228406.html)]([http://en.people.cn/n3/2024/1011/c90000-20228406.html](http://en.people.cn/n3/2024/1011/c90000-20228406.html)), accessed on 11 October 2024). This indicates that the immense energy of the solar wind directly affected mid- to high-latitude regions during the event, further highlighting the significant importance of conducting in-depth research on this phenomenon. Field-aligned currents (FACs) serve as the primary mechanism for transferring energy and momentum between the magnetosphere and ionosphere. Polar electrojets (PEJs) flow transversely to the ionospheric electric and magnetic fields in the E region and can significantly impact electrical infrastructure by generating geomagnetically induced currents on the ground [2]. Consequently, comprehending storm-time FACs and PEJs is essential for understanding the complex interactions that drive space weather and its terrestrial effects. Additionally, since the latitudes of FACs and PEJs can indicate auroral locations, this study could provide observational evidence for the occurrence of auroras at mid-latitudes. Previous studies have investigated the latitudinal evolution of FACs during storms. For example, [PERSON] et al. (1992) [3] documented dynamic variations in FACs during the 13-14 March 1989 storm, noting that the latitudinal extent of the FAC region expanded, particularly in the evening sector. [PERSON] et al. (2002) [4] used Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) data to analyze variations in FAC intensity and the poleward retreat speed during two geomagnetic storm recovery phases. They found that during storms with rapid recovery, the FAC intensity returned to pre-storm levels in one hour, together with a swift poleward retreat. By contrast, storms with a gradual recovery exhibited slower poleward movement and sustained strong FACs. Several studies have explored the relationship between storm-time FACs, PEJs, interplanetary magnetic field (IMF), and geomagnetic indices. However, there are still challenges in predicting the density and latitudinal evolution of FACs and PEJs during geomagnetic storms. [PERSON] et al. (2006) [5] analyzed FACs using Challenging Minisatellite Payload (CHAMP) satellite data during the strong geomagnetic storms of October and November 2003, finding a strong correlation between the strength of dayside FACs and Pd, with the equatorward shift in dayside FACs mainly influenced by southward IMF Bz. Meanwhile, the latitudinal variations in nightside FACs were more strongly associated with Disturbance storm time (Dst). [PERSON] et al.