This study analyzes strong sporadic E layer (Es) formation in Boa Vista (BV, 2.8°N, 60.7°W, dip: 18°), a low‐latitude region in the Brazilian sector, which occurred far after the onset of a magnetic storm recovery phase. Such occurrences were observed during seven magnetic storms with available data for BV. Thus, the ionospheric behavior on days around the magnetic storm that occurred on 20 January 2016 was investigated to search for possible explanations. This analysis indicated that the probable mechanism acting during the Es layer strengthening is the zonal westward electric field caused by a disturbance dynamo. The same evidence was also observed in two other magnetic storms at the same location. Hence, a numerical model of the E region dynamics, called MIRE (Portuguese acronym for E Region Ionospheric Model), was used to confirm whether the disturbance dynamo could cause the Es layer intensification. The inputs for the model were the electric field deduced from the vertical drift and the wind components provided by GSWM‐00 model. The simulations indicate that the Es layer density is significantly enhanced when the zonal electric field is present compared to the reference scenario with only the winds. Therefore, it is concluded that the disturbance dynamo electric field is the likely cause of the strong Es layers in the analyzed cases. Finally, the combined results from the model and observational data seem to contribute significantly to advance our understanding of the role of the electric fields in the Es layer formation at low latitudes.

中文翻译：

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扰动发电机电场对Boa Vista上强零星E层形成的影响，Boa Vista是美国地区的一个低纬度站

这项研究分析了Boa Vista（BV，2.8°N，60.7°W，倾角：18°）中强烈的零星E层（Bs），这是巴西板块的一个低纬度地区，发生在很早就发生了磁风暴恢复阶段。可以通过BV的可用数据在7次磁暴中观察到这种情况。因此，对2016年1月20日发生的磁暴周围几天的电离层行为进行了调查，以寻找可能的解释。分析表明，在Es层强化过程中​​起作用的可能机制是由扰动发电机引起的纬向西向电场。在同一地点的另外两次磁暴中也观察到了相同的证据。因此，E的数值模型区域动态，称为MIRE（葡萄牙语，E的缩写，区域电离层模型）用于确认发电机是否会引起Es层增强。该模型的输入是由GSWM-00模型提供的垂直漂移和风分量推导出的电场。仿真表明，与仅带风的参考情景相比，当存在区域电场时，Es层密度显着提高。因此，可以得出结论，在分析的情况下，扰动发电机电场是强Es层的可能原因。最后，来自模型和观测数据的组合结果似乎对促进我们进一步了解电场在低纬度Es层形成中的作用做出了重要贡献。