We present observations of broadband (∼10–50 mHz) Pc3–Pc4 waves on 4 January 2014. The waves were detected on the dayside simultaneously in a compressional component (δ B _z ) at the Radiation Belt Storm Probes A (RBSP‐A) in the inner magnetosphere and in the north‐south component (δ H ) on the ground at a low‐latitude Bohyun (BOH) station (L  = 1.3) during an interval of small interplanetary magnetic field cone angle, suggesting that upstream ultralow frequency (ULF) waves were the source of the magnetospheric Pc3–Pc4 waves. We observed the ground‐satellite high coherence between RBSP‐A δ B _z and BOH δ H for a prolonged time interval lasting 6.5 hr, which has not been reported previously, during which RBSP‐A was on the inbound and outbound legs moving from L  = ∼3.3 to ∼6.3. In order to understand the spatial mode structure of the compressional waves, we examined the ground‐satellite cross phase for the high‐coherence interval and found that the waves observed in and out of the plasmasphere propagated earthward at the average fast‐mode speed of ∼700–1,000 km/s. We also observed cross‐phase values smoothly changing with the radial distance of the spacecraft across the plasmapause. This indicates that the presence of the plasmapause has little effect on our fast‐mode waves propagating into the inner magnetosphere and to the ground low‐latitude station.

中文翻译：

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持久的卫星日间Pc3–Pc4脉动的高相干性

我们在2014年海浪1月4日宽带（~10-50 MHZ）PC3-PC4波的本观察结果的向阳面在压缩部件同时（检测δ乙_Ž）在辐射带风暴探头A（RBSP-A）在内磁层和在南北组分（δ H ^）在地面上在低纬度Bohyun（BOH）站（大号 小星际磁场锥角的间隔期间= 1.3），这表明上游超低频率（ ULF）波是磁层Pc3–Pc4波的来源。我们观察到RBSP-A之间地面卫星高相干性δ乙_Ž和BOH δ ħ持续时间长达6.5小时，这是以前未曾报告的，在此期间，RBSP‐A在入站和出站 路段上从L =〜3.3移至〜6.3。为了了解压缩波的空间模式结构，我们检查了高相干间隔的地-卫星交叉相位，发现在等离子层内外观察到的波以〜的平均快模速度向地球传播。 700–1,000 km / s。我们还观察到跨相值随航天器在等离子暂停之间的径向距离而平滑变化。这表明等离子暂停的存在对传播到内部磁层和地面低纬度站的快速模式波影响很小。