The low‐latitude ionospheric TEC observed by the Beidou geostationary satellite showed large enhancement during 27–30 August 2018 of the storm recovery phase. The cause of the positive ionospheric storm during the recovery phase has yet to be resolved. In this study, multiple observations, including aurora, high‐latitude convection, potential, and the TEC maps, were used to study the contributions from the high‐speed solar wind to the ionosphere during the recovery phase of the storm. It was found that the high‐speed solar wind was effective in modulating the intensity and the size of the auroral oval, high‐latitude convection, and potential pattern. The Thermosphere Ionosphere Electrodynamics General Circulation Model generally reproduced the observed evolution of the ionosphere at high latitudes during the recovery phase of the storm, and it was used to quantitatively investigate the effects of the high‐speed solar wind on the recovery phase ionosphere. The results suggested that the high‐speed solar wind caused increase of TEC at auroral oval was about 2 TECU. The high‐speed solar wind, combined with oscillating interplanetary magnetic field Bz, led to the enhancement of the low‐latitude prompt penetrating electric fields and increased the low‐latitude TEC of about 2 TECU. Therefore, the high‐speed solar wind was a possible driver to the ionospheric positive storm during the recovery phase, but the causes for the more than 10‐TECU enhancement at low and middle latitudes during the recovery phase of this event are unknown.

中文翻译：

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2018年8月地磁风暴的恢复阶段，高速太阳风在电离层上的印记

北斗对地静止卫星观测到的低纬度电离层TEC在风暴恢复阶段的2018年8月27日至30日期间显示出大幅增强。恢复阶段电离层正风暴的原因尚未解决。在这项研究中，使用了包括极光，高纬度对流，势能和TEC图在内的多种观测资料，以研究风暴恢复阶段高速太阳风对电离层的贡献。结果发现，高速太阳风在调节极光椭圆的强度和大小，高纬度对流和势能模式方面是有效的。热球电离层电动力学通用环流模型大致再现了风暴恢复阶段高纬度电离层的观测演变，并用于定量研究高速太阳风对恢复相电离层的影响。结果表明，高速太阳风引起极光椭圆处TEC的增加约为2 TECU。高速太阳风结合行星际磁场Bz的振荡，导致低纬度瞬态穿透电场的增强，并使低纬度TEC增加了约2 TECU。因此，在恢复阶段，高速太阳风可能是电离层正风暴的驱动因素，但在此事件的恢复阶段，低纬度和中纬度地区增强10-TECU以上的原因尚不清楚。结果表明，高速太阳风引起极光椭圆处TEC的增加约为2 TECU。高速太阳风结合行星际磁场Bz的振荡，导致低纬度瞬态穿透电场的增强，并使低纬度TEC增加了约2 TECU。因此，在恢复阶段，高速太阳风可能是电离层正风暴的驱动因素，但在此事件的恢复阶段，低纬度和中纬度地区增强10-TECU以上的原因尚不清楚。结果表明，高速太阳风引起极光椭圆处TEC的增加约为2 TECU。高速太阳风结合行星际磁场Bz的振荡，增强了低纬度瞬态穿透电场，并增加了约2 TECU的低纬度TEC。因此，在恢复阶段，高速太阳风可能是电离层正风暴的驱动因素，但在此事件的恢复阶段，低纬度和中纬度地区增强10-TECU以上的原因尚不清楚。