We report observations of the whistler mode waves in the magnetic reconnection region at the dayside magnetopause using the magnetospheric multiscale (MMS) mission on January 11, 2016. In this event, whistlers mostly occur on the magnetospheric side of the reconnection central plane and are closely related to counter‐streaming electron beams in the medium energy range (200–300 eV). These counter‐streaming electron beams can be attributed to the accelerated magnetosheath electrons by the reconnection. Through quantitatively testing the Landau resonance condition and solving the kinetic dispersion relations, we present the evidence for whistler excitation by electron beams in the medium energy range. Additionally, the whistlers are observed simultaneously with the pitch‐angle scattering of electrons in the high‐energy range (300–3,000 eV). The calculation results show that this scattering is likely to occur through electron cyclotron wave‐particle interactions, which can isotropize electrons and exchange energy between plasmas and waves.

中文翻译：

---

日间磁更年期磁重连区中光束驱动的惠斯勒模式波的观测

我们使用磁层多尺度（MMS）任务于2016年1月11日报告了在白天磁更年期磁重连接区中的惠斯勒模式波的观测结果。在这种情况下，啸声大多发生在重连接中心平面的磁层一侧，并且紧密与中等能量范围（200–300 eV）中的逆流电子束有关。通过重新连接，这些逆流电子束可以归因于加速的磁石电子。通过定量测试Landau共振条件并解决动力学色散关系，我们为中等能量范围内的电子束产生的哨声激发提供了证据。此外，在高能量范围（300–3,000 eV）内，同时观察到了啸叫声和电子的俯仰角散射。