We used reanalyzed Jicamarca radar measurements to study the response of equatorial ionospheric electrodynamics and spread F during the main phase of the large September 2017 geomagnetic storm. Our observations near dusk on 7 September show very large upward drifts followed by a large short-lived downward drift perturbation that completely suppressed the lower F region plasma irregularities and severely decreased the backscattered power from the higher altitude spread F. We suggest that this large short-lived westward electric field perturbation is most likely of magnetospheric origin and is due to a sudden and very strong magnetic field reconfiguration. Later in the early night period, data indicate large, mostly upward, drift perturbations generally consistent with standard undershielding and overshielding electric field effects, but with amplitudes significantly larger than expected. Our analysis suggests that occurrence of storm-time substorms is one of the major factors causing the large nighttime westward and eastward electric field perturbations observed at Jicamarca near the storm main phase. Our analysis also suggests that magnetospheric substorms play far more important roles on the electrodynamics of the equatorial nighttime ionosphere than has generally been thought.

中文翻译：

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2017 年 9 月地磁风暴期间对 Jicamarca 的快速渗透和亚暴效应

我们使用重新分析的 Jicamarca 雷达测量结果来研究 2017 年 9 月大地磁暴主要阶段赤道电离层电动力学和传播 F 的响应。我们在 9 月 7 日黄昏附近的观测显示非常大的向上漂移，然后是一个大的短暂的向下漂移扰动，完全抑制了低 F 区等离子体的不规则性，并严重降低了高海拔传播 F 的反向散射功率。我们建议这个大的短- 存在的西向电场扰动最有可能是磁层起源，并且是由于突然且非常强的磁场重构。在深夜后期，数据表明大的，主要是向上的漂移扰动，通常与标准的欠屏蔽和过屏蔽电场效应一致，但幅度明显大于预期。我们的分析表明，风暴时间亚暴的发生是导致在风暴主相附近的 Jicamarca 观测到的夜间大的西向和东向电场扰动的主要因素之一。我们的分析还表明，磁层亚暴对赤道夜间电离层的电动力学所起的作用比人们普遍认为的要重要得多。