Fast magnetosonic (MS) waves are excited by the ring distribution of energetic protons preferably when the ring velocity (V_R) is within a factor of 2 above or below the local Alfvén speed (V_A). Here we examine the global distributions of MS waves and proton rings with 0.5V_A ≤ V_R ≤ 2V_A based on 64 months (from October 25, 2012 to February 28, 2018) of Van Allen Probes observations. The statistical results show that MS waves are present over a broad region of L = 1.2–6.0 and 00–24 magnetic local time (MLT), with a higher occurrence rate at L = 2.5–5.5 on the dayside. Proton rings occur mainly on the dayside of L > 5.0. During active geomagnetic periods, both MS waves and proton rings occur more frequently and extend to low L‐shells. The current results provide the further observational evidence that MS waves can be excited by proton rings at a distant region and propagate to low L‐shells.

中文翻译：

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辐射带中磁声波与质子环全球分布的相关观测

快磁（MS）波用高能质子的环分布激发优选当环速度（V _{- [R} ）为2的上方或下方的本地阿尔芬速度（倍之内V_甲）。在这里，我们考察全球MS波和质子环与0.5分布V_甲 ≤  V _ř  ≤2 V_阿基于在64个月（从2012年10月25日到2018年2月28日）范艾伦探测器观测。统计结果表明，MS波存在于L  = 1.2–6.0和00-24磁性本地时间（MLT）的较宽区域，在L处的发生率更高 =白天2.5–5.5。质子环主要发生在L  > 5.0的白天。在活跃的地磁期间，MS波和质子环都更频繁地出现并延伸到低L壳层。目前的结果提供了进一步的观察证据，即MS波可以被远处的质子环激发并传播到低L壳层。