In situ evidence of the modification of the parallel propagation of EMIC waves by heated He+ ions
In situ evidence of the modification of the parallel propagation of EMIC waves by heated He+ ions
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DOI：
10.1002/2016ja022573
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Z. Yuan;Xiongdong Yu;Dedong Wang;Shiyong Huang;Haimeng Li;T. Yu;Zheng Qiao;J. Wygant;H. Fu
中科院分区：
文献类型：
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作者：
Z. Yuan;Xiongdong Yu;Dedong Wang;Shiyong Huang;Haimeng Li;T. Yu;Zheng Qiao;J. Wygant;H. Fu
通过对范艾伦探测器 B 的观察，我们报告了加热 He+ 离子对平行传播电磁离子回旋加速器 (EMIC) 波的修改的现场证据。在等离子体层的外边界，伴随着He+离子的加热，EMIC波的H+和He+频段相互融合，导致冷等离子体中He+离子的回旋频率（ΩHe+）和H+截止频率（ωH+co）之间的通常阻带消失。此外，利用观测到的等离子体参数理论上计算出的EMIC波的色散关系也表明EMIC波确实可以在ΩHe+上平行传播。因此，本文提供了加热 He+ 离子对 EMIC 波平行传播的改变的原位证据。
With observations of the Van Allen Probe B, we report in situ evidence of the modification of the parallel propagating electromagnetic ion cyclotron (EMIC) waves by heated He+ ions. In the outer boundary of the plasmasphere, accompanied with the He+ ion heating, the frequency bands of H+ and He+ for EMIC waves merged into each other, leading to the disappearance of a usual stop band between the gyrofrequency of He+ ions (ΩHe+) and the H+ cutoff frequency (ωH+co) in the cold plasma. Moreover, the dispersion relation for EMIC waves theoretically calculated with the observed plasma parameters also demonstrates that EMIC waves can indeed parallel propagate across ΩHe+. Therefore, the paper provides an in situ evidence of the modification of the parallel propagation of EMIC waves by heated He+ ions.