The Magnetospheric Multiscale mission (MMS1) data for 8 months in the winter periods of 2017–2018 and 2018–2019, when MMS had its apogee in the upstream solar wind of the Earth's bow shock, are used to study linear magnetic holes (LMHs). These LMHs are characterized by a magnetic depression of more than 50 % and a rotation of the background magnetic field of less then 10^∘. A total of 406 LMHs are found and, based on their magnetoplasma characteristics, are split into three categories: cold (increase in density, little change in ion temperature), hot (increase in ion temperature, decrease in density) and sign change (at least one magnetic field component changes sign). The occurrence rate of LMHs is 2.3 per day. All LMHs are basically in pressure balance with the ambient plasma. Most of the linear magnetic holes are found in ambient plasmas that are stable against the mirror-mode generation, but only half of the holes are mirror-mode-stable inside.

中文翻译：

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地球附近线性磁孔结构的统计研究

2017-2018年和2018-2019年冬季，磁层多尺度任务（MMS1）的数据为8个月，当时MMS处于地球弓激波的上游太阳风中，用于研究线性磁孔（LMH） 。这些LMHs的特征为超过50％的磁性抑郁的再少的背景磁场的旋转10 ^∘。共发现406个LMH，并根据其磁浆特性将其分为三类：冷（密度增加，离子温度变化很小），热（离子温度升高，密度降低）和符号变化（在至少一个磁场分量会改变符号）。LMH的发生率为每天2.3。所有LMH基本上都与周围等离子体处于压力平衡状态。在周围等离子体中发现了大多数线性磁性孔，这些等离子体对镜像模式的产生是稳定的，但是内部只有一半的孔是镜像模式稳定的。