Ionospheric GPS-TEC responses from equatorial region to the EIA crest in the South American sector under intense space weather conditions

We present and discuss the ionospheric F-region observations from equator to equatorial ionization anomaly (EIA) regions over South American sector during an intense space weather event occurred between 27 May 29, 2017. During this geomagnetic storm, symmetric-H (SYM-H) reached a minimum of −142 nT at ∼0700 UT on 28, For investigation, we analyze vertical total electron content (VTEC) chain nearly 120 Global Positioning System (GPS) stations. Magnetometer measurements obtained two stations in low latitude are also presented. The do not indicate prompt penetration electric field (PPEF) effects VTEC variations. Magnetometer's Cuiabá (CBA) Cachoeira Paulista (CXP) central west south parts Brazil, respectively, have shown strong cross-correlation with SYM-H period 3 48 h. results show positive storm phase recovery Positive effect is possibly associated disturbances winds. phase, intensification EIA took place, related additional effect. values differences east sectors. This indicates that crest stronger than sector, due combination disturbance wind geometry where lines more inclined. • Study GPS used. phase.