We use Van Allen Probes (Radiation Belt Storm Probes A and B, henceforth RBSP-A and RBSP-B) and GOES-13 and GOES-15 (henceforth G-13 and G-15) multipoint magnetic field, electric field, plasma, and energetic particle observations to study the spatial, temporal, and spectral characteristics of compressional Pc5 pulsations observed during the recovery phase of a strong geomagnetic storm on 1 January 2016. From ∼ 19:00 to 23:02 UT, successive magnetospheric compressions enhanced the peak-to-peak amplitudes of Pc5 waves with 4.5–6.0 mHz frequencies from 0–2 to 10–15 nT at both RBSP-A and RBSP-B, particularly in the prenoon magnetosphere. Poloidal Pc4 pulsations with frequencies of ∼ 22–29 mHz were present in the radial Bx component. The frequencies of these Pc4 pulsations diminished with increasing radial distance, as expected for resonant Alfvén waves standing along field lines. The GOES spacecraft observed Pc5 pulsations with similar frequencies to those seen by the RBSP but Pc4 pulsations with lower frequencies.Both RBSP-A and RBSP-B observed frequency doubling in the compressional component of the magnetic field during the Pc5 waves, indicating a meridional sloshing of the equatorial node over a combined range in Z_SM from 0.25 to −0.08 Re, suggesting that the amplitude of this meridional oscillation was ∼ 0.16 Re about an equatorial node whose mean position was near $Z_{\text{SM}}=\sim \mathrm{0.08}$ Re. RBSP-A and RBSP-B HOPE (Helium Oxygen Proton Electron) and MagEIS (Magnetic Electron Ion Spectrometer) observations provide the first evidence for a corresponding frequency doubling in the plasma density and the flux of energetic electrons, respectively. Energetic electron fluxes oscillated out of phase with the magnetic field strength with no phase shift at any energy. In the absence of any significant solar wind trigger or phase shift with energy, we interpret the compressional Pc5 pulsations in terms of the mirror-mode instability.

中文翻译：

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日间磁层中Pc5压缩脉动的多点观测和相应的粒子特征

我们使用Van Allen探头（辐射带风暴探头A和B，以下简称RBSP-A和RBSP-B）以及GOES-13和GOES-15（以下称为G-13和G-15）多点磁场，电场，等离子，和高能粒子观测，以研究在2016年1月1日强地磁风暴恢复阶段观测到的压缩Pc5脉动的时空，频谱特征。从 UT约19:00至23:02，连续的磁层压缩使峰值达到峰值。在RBSP-A和RBSP-B处，从0-2到10-15 nT，频率为4.5-6.0 mHz的Pc5波的峰间振幅，特别是在午前磁层。倍频Pc4脉动，频率为〜 径向Bx分量中存在22–29 mHz。这些Pc4脉动的频率随着径向距离的增加而减小，这是沿电场线站立的共振Alfvén波所期望的。GOES航天器观测到的Pc5脉冲的频率与RBSP所见的频率相似，但Pc4脉冲的频率较低.RBc-A和RBSP-B都在Pc5波期间观察到磁场压缩分量的频率增加了一倍，表明子午向晃动过在组合范围中的赤道节点的ž _SM 从0.25至-0.08  RE，这表明该子午振动的振幅为〜  0.16重约赤道节点，其平均位置为近${ž}_{\text{SM}}=〜\mathrm{0.08}$ 回覆。RBSP-A和RBSP-B HOPE（氦氧质子电子）和MagEIS（磁电子离子光谱仪）的观测结果分别提供了分别使等离子体密度和高能电子通量相应增加一倍的证据。高能电子通量与磁场强度异相振荡，在任何能量下都没有相移。在没有任何明显的太阳风触发或能量相移的情况下，我们根据镜面模式的不稳定性来解释压缩的Pc5脉动。