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Abstract:
In this study, we performed a detailed analysis of the ionospheric zonal currents from equator to middle latitudes during the recent intense geomagnetic storm on 10–12 May 2024. Magnetic measurements from two ground stations in the America sector as well as those from the Swarm satellites have been used. Extreme intensified eastward and westward EEJ values reaching 300 and −400 mA/m have been observed during the storm main and recovery phases, respectively. Such intense EEJ values have never been observed during the past 11-year flying period of Swarm mission. In addition, the storm responses of zonal currents at low and middle latitudes have been analyzed using the vertical magnetic field component from Swarm. These zonal currents showed quite prominent dependence on magnetic local time. In the noon sector, eastward currents were dominated under both quiet and storm conditions, with slight intensification during the storm. Conversely, the zonal currents in the dawn and dusk sectors displayed abrupt current reversals within 30 min after the storm sudden commencement, characterized by sustained eastward (dawn) and westward (dusk) perturbations persisting for the rest of one and a half days. Most interestingly, two eastward zonal current jets were found located at ±25° magnetic latitudes at the dusk sector and emerged with westward zonal currents at other low and middle latitudes. We speculate that a shear layer of zonal eastward winds is needed at a conjugate altitude to cause the narrow eastward current jets. To our knowledge, this is the first report of such narrow current jets at middle latitudes during storms.
