Fagundes, Paulo RobertoPillat, Valdir GilHabarulema, John BoscoMuella, Marcio Tadeu de Assis HonoratoVenkatesh, KavutarapuAbreu, Alessandro José deAnoruo, Chukwuma MosesVieira, FranciscoWelyargis, Kibrom HadushAgyei-Yeboah, EbenezerTardelli, AlexandreFelix, Gabriela de SousaPicanço, Giorgio Arlan da Silva2025-08-152025-08-15https://repositorio.univap.br/handle/123456789/1021Between May 10–15, 2024, a geomagnetic superstorm, the most intense in the past two decades, was recorded. This G5-level super- storm exhibited a Disturbance Storm Time (Dst) index of −412 nT and a Kp index of 9. The sudden storm commencement (SSC) occurred on May 10 at 17:05 UT, followed by the main phase from 18:00 UT on May 10 to 03:00 UT on May 11. The recovery phase lasted from 03:00 UT on May 11 until May 15. During this period, nine X-class solar flares were observed, indicating intense solar activ- ity. The superstorm led to significant ionospheric disturbances, which were analyzed using data from two ionosonde stations and GPS- TEC data from a network across the American sector, covering equatorial to low-mid latitude regions. A negative storm effect was observed in the equatorial region, while a positive ionospheric effect was observed in the low-mid latitudes during the main phase, accom- panied by the uplift of the F-layer to altitudes exceeding 1024 km, driven by storm induced prompt penetration electric fields. Addition- ally, a strong negative storm effect was recorded during the recovery phase on May 11 in daytime, probably due to O/N2 ratio changes.PDFen-USArtigos de PeriódicosAdvances in Space Research10.1016/j.asr.2025.02.007Geomagnetic stormCoraonal Mass EjectionEquatorial Ionization AnomalyIonospheric responseFAGUNDES, P. R. et al. Equatorial Ionization anomaly disturbances (EIA) triggered by the May 2024 solar Coronal Mass Ejection (CME): The strongest geomagnetic superstorm in the last two decades. Advances in Space Research, p. 1-15, 2025. Disponível em: 10.1016/j.asr.2025.02.007.Universidade do Vale do ParaíbaSouth African National Space AgencyRhodes UniversityNorth-West UniversityPhysical Research LaboratoryInstituto Nacional de Pesquisas EspaciaisInstituto Tecnológico de AeronáuticaInstituto Federal de Tocantins