Simultaneous Observation of Whistler Waves and Electron Cyclotron Harmonic Waves in the Separatrix Region of Magnetopause Reconnection

作者：Xiancai Yu, Quanming Lu, Rongsheng Wang, Xinliang Gao, Longlong Sang, Shui Wang · 发表于：Journal of Geophysical Research Space Physics · 年份：2021 · DOI：10.1029/2021ja029609 · 被引用次数：11 · 研究领域：Ionosphere and magnetosphere dynamics、Solar and Space Plasma Dynamics、Magnetic confinement fusion research

Abstract A variety of plasma waves have been observed in the separatrix region during magnetic reconnection, and their roles on reconnection and exciting mechanisms are still controversial. In this paper, we report the whistler wave with a very narrow frequency band just above half of the electron cyclotron frequency in the separatrix region. This whistler wave is accompanied with the electron cyclotron harmonic (ECH) waves. The ECH waves have frequencies between the first and fifth harmonic of electron cyclotron frequency . The wave normal angle of the whistler waves is ∼20°–∼40°, meaning the quasi‐parallel propagation, while the ECH waves propagate perpendicular to the background magnetic field with . In the separatrix region, the electrons have a loss‐cone distribution while these two kinds of waves are observed. Based on the linear theory, such an electron distribution is unstable for both whistler waves and ECH waves. It indicates that these two kinds of waves are generated by the electron loss‐cone instability.