Non-monochromatic whistler waves detected by Kaguya on the dayside surface of the moon
Non-monochromatic whistler waves detected by Kaguya on the dayside surface of the moon
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DOI：
10.5047/eps.2010.01.005
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发表时间：
2011-02
期刊：
影响因子：
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通讯作者：
T. Nakagawa;F. Takahashi;H. Tsunakawa;H. Shibuya;H. Shimizu;M. Matsushima
中科院分区：
文献类型：
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作者：
T. Nakagawa;F. Takahashi;H. Tsunakawa;H. Shibuya;H. Shimizu;M. Matsushima
卡古亚在月球表面以上100公里的高度探测到了0.03-10赫兹频率范围内磁场的非单色波动。这种波动几乎总是在月球的太阳一侧观察到，而与当地的月球壳场无关。它们也只是在终结点(SZA<；123°)的夜间被检测到，但在尾流中心附近没有发现。波动幅度在0.03~10赫兹范围内增强，没有明显的峰值频率。涨落具有压缩成分，偏振不明显。这些波动被认为是由月球表面反射的质子产生的哨声波。反射的质子在不同的方向上散射，导致平行于磁场的速度分量的大范围分布。它可以解释通过波与反射离子的回旋共振所观察到的较宽的频率范围，其中共振频率取决于平行于磁场的速度分量。然而，也有可能这些波是由某种非共振过程产生的。
Non-monochromatic fluctuations of the magnetic field over the frequency range of 0.03–10 Hz were detected by Kaguya at an altitude of 100 km above the lunar surface. The fluctuations were almost always observed on the solar side of the moon, irrespective of the local lunar crustal field. They were also detected just nightside of the terminator (SZA < 123°), but were absent around the center of the wake. The level of the fluctuation enhanced over the wide range from 0.03 to 10 Hz, with no clear peak frequency. The fluctuations had the compressional component, and the polarization was not clear. The fluctuations were supposed to be whistler waves generated by the protons reflected by the lunar surface. The reflected protons are scattered in various directions, resulting a wide range of distribution of the velocity component parallel to the magnetic field. It may account for the wide range of frequency as observed, through cyclotron resonance of the wave with the reflected ions, in which the resonant frequency depends on the velocity component parallel to the magnetic field. However, there is also the possibility that the waves were generated by some nonresonant process.