Speaker
Description
R. de Jesus[1,2,3], G. Yang[1], A.A. Pimenta[3], A.J. de Abreu[3,4], G.A.S. Picanço[5], A.M. Santos[2,3], L.C.A. Resende[2,3], C.S. Carmo[1,2,3], L.F.R. Vital[1,2,3], I.S. Batista[3], J.R. Souza[3], K. Venkatesh[6], P.R. Fagundes[7], V.F. Andrioli[2,3], P.P. Batista[3], M.P.P. Martins[3], C. Wang[1], H. Li[1], Z. Liu[1], R.B. Kerr[8], L.V. Peres[9], R. da Silva[9]
[1]State Key Laboratory of Space Weather, National Space Science Center/Chinese Academy of Sciences, Beijing, China, [2]China-Brazil Joint Laboratory for Space Weather, National Space Science Center, São José dos Campos, Brazil, [3]National Institute for Space Research (INPE), São José dos Campos, Brazil, [4]Instituto Tecnológico de Aeronáutica (ITA), Divisão de Ciências Fundamentais, São José dos Campos, SP, Brazil, [5]Space Science Laboratory, University of Massachusetts Lowell, Lowell, MA, USA, [6]Physical Research Laboratory, Ahmedabad, India, [7]Universidade do Vale do Paraíba /IP & D, São José dos Campos, SP, Brazil, , [8]Computational Physics Inc., Lowell, MA, US, [9]Universidade Federal do Oeste do Pará (UFOPA), Santarém, Pará, Brazil.
Abstract
In this investigation, we present and discuss the response of the ionospheric F-layer in the Brazilian sector during a weak and intense geomagnetic storm in April 2025. The weak and intense storm investigated in this study show a minimum Dst of -33 nT on 15 April followed by -138 nT on 16 April. We present the variations of vertical total electron content (VTEC) and ionospheric F-layer parameters (h´F, hmF2, and foF2) obtained from Global Navigation Satellite System (GNSS) receivers and ionosondes, respectively, in the equatorial and low-latitude region. Also, Global-scale Observation of the Limb and Disk (GOLD), Fabry-Perot interferometer (FPI), and O/N2 ratio data are presented. During both storms, multiple prompt penetration electric fields (PPEFs) occurred. During the recovery phase of the intense storm, the pre‐reversal enhancement in the equatorial region was suppressed due to the westward PPEF, resulting in the suppression of the equatorial plasma bubbles (EPBs). The combined effect of equatorward thermospheric winds and the eastward PPEF caused abnormal upward movements in the ionosphere, resulting in positive ionospheric storms in both events. At low latitudes, negative ionospheric storms occurred due to changes in the O/N₂ ratio.