文章基本信息

标题：Double-frequency oscillations of low energy plasma associated with transverse Pc 5 pulsations: GEOTAIL satellite observations
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作者：Tohru Sakurai ; Yutaka Tonegawa ; Takuya Kitagawa 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2014
卷号：51
期号：1
页码：43-53
DOI：10.1186/BF03352208
出版社：Springer Verlag
摘要：The GEOTAIL satellite observed an interesting oscillation phenomenon of low energy plasma (LEP) in the dawnside outer magnetosphere. The oscillation was taking place with a frequency double that of the transverse oscillation of Pc 5 pulsations. The double-frequency oscillation appeared in the plasma density and temperature, clearly showing an out-of-phase relationship between them. However, this phenomenon is revealed to be an instrumental effect of the LEP detector, which has a low energy threshold of measuring an ion population at 32 eV/Q. The imbedded ion population is found to be composed of cold ions with an energy of less than the threshold. They are convected past the LEP detector by the Pc 5 wave and enter the detector energy window twice per wave period. Plasma bulk parameters calculated using the detected ions produce an oscillation that has a frequency exactly double that of the Pc 5 wave. However, it should be noted that this phenomenon is observed with a large amplitude electric field oscillation only in intervals when the satellite passes through the dawnside outer magnetosphere under very quiet magnetic conditions, i.e., periods of the northward interplanetary magnetic field.