Abstract

We considered wave disturbances of the Pi2 type geomagnetic field (periods of 1–2 min) recorded simultaneously by magnetometers at low-latitude stations in Africa and on low-orbit SWARM satellites both during the beginning of a substorm and in non-substorm periods. At night, Pi2 waves in the upper ionosphere and on Earth are almost identical in amplitude and in phase. These waves on the satellite mainly manifest themselves in longitudinal (along the geomagnetic field) and radial magnetic components. A comparison of the observational results with the model of the interaction of MHD waves with the ionosphere–atmosphere–Earth system shows that night low-latitude Pi2 signals are generated by magnetospheric fast magnetosonic waves propagating to the Earth through the opacity region. The results of analytical estimates and numerical simulations are consistent with the properties of Pi2 signals recorded in the upper ionosphere and on Earth.

中文翻译：

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根据SWARM卫星和地面站的观测，低纬度Pi2波

摘要

我们考虑了在非洲低纬度站和低轨道SWARM上用磁力计同时记录的Pi2型地磁场波扰动（周期为1-2分钟）在亚暴开始和非亚暴期间都装有卫星。到了晚上，电离层上部和地球上的Pi2波的振幅和相位几乎相同。卫星上的这些波主要表现在纵向（沿地磁场）和径向磁分量中。将观测结果与MHD波与电离层-大气-地球系统的相互作用模型进行的比较表明，夜间低纬度Pi2信号是由通过不透明区传播到地球的磁层快速磁声波产生的。分析估计和数值模拟的结果与记录在电离层上部和地球上的Pi2信号的性质一致。