In this work, the occurrence of different types of sporadic-E layers (Es) was described for two stations located in the region of the South America Magnetic Anomaly: Jataí and São José dos Campos. The results show the hourly and monthly values of the Es occurrences and presented five types of layers (cusp, high, flat, low, and slant), with the flat/low types (Es f/l ) being the most frequent over both stations. We also analyzed the Es layer parameters of blanketing frequency (f b Es) and top frequency (f t Es) obtained from ionosonde data during storm-time periods, in order to investigate possible evidences of energetic particle-induced E-layer ionization. The results revealed increases in the values of the nighttime f t Es and f b Es, which can be related to the particle precipitation in the South America Magnetic Anomaly region. Additionally, we investigated the roles of the wind shear mechanism in the formation of the Es types by using a modified form of the Ionospheric E-Region Model (MIRE), which incorporates tidal winds obtained from meteor radar data. Furthermore, the electron densities deduced from f b Es parameter were compared with the maximum electron densities obtained from MIRE simulations. Depending on local time and season, the initial results revealed for both stations some discrepancies between modeled and measured electron densities. However, a better fitting was obtained when the amplitudes of the zonal/meridional wind components were adjusted by some factor, which may be attributed to the possible effects of day-to-day tidal wind variability and their interaction with gravity and planetary waves.Key Points:• The flat/low Es are the most frequent types of sporadic layers observed at the low-latitude stations • Es frequency parameters during moderate storms showed evidences of energetic particle-induced E-layer ionization around the SAMA region • Modeled and measured electron densities revealed the role of the wind shear mechanism in the formation of the observed Es layers

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The equatorial (Esq) and blanketing (Esb) sporadic (Es) layers occur due to the Equatorial Electrojet Current (EEJ) plasma instabilities and tidal wind components, respectively. Both Esq and Esb layers can appear concurrently over some Brazilian equatorial regions due to the peculiar geomagnetic field configuration in this sector. Previous works indicate that the inclination angle limit for the Esq occurrence in ionograms is 7°. However, we found evidence that regions more distant can also experience such equatorial dynamics during disturbed periods. In this context, we deeply investigated this EEJ influence expansion effect by analyzing the Esq layers in regions not so close to the magnetic equator during a high‐speed solar wind stream event that occurred on May 05 and 06, 2018. To explain these atypical Esq layer occurrences, we considered the Es layer parameters obtained from digital ionosondes over the Brazilian regions, São Luís (dip: 9.5°), and Araguatins (dip: 10.5°). We use magnetometer data and a model named MIRE (E Region Ionospheric Model) to validate this mechanism. The results show that the eastward electric field of the Gradient Drift instability in the EEJ is effective during the magnetic storm main phase in the boundary equatorial magnetic sites, creating the Esq layers. Thus, the EEJ plasma irregularity superimposes the wind shear mechanism, changing the Es layer dynamics during disturbed periods over the magnetic equator boundary sites. Therefore, this work establishes new findings of the EEJ influence expansion dynamics in the Es layer formation over the Brazilian regions, which was considered in MIRE for the first time.