Photoelectrons in the Enceladus plume
Photoelectrons in the Enceladus plume
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DOI：
10.1002/jgra.50495
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发表时间：
2013-08
期刊：
影响因子：
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通讯作者：
A. Coates;A. Wellbrock;G. Jones;J. Waite;P. Schippers;M. Thomsen;C. Arridge;Robert L. Tokar
中科院分区：
文献类型：
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作者：
A. Coates;A. Wellbrock;G. Jones;J. Waite;P. Schippers;M. Thomsen;C. Arridge;Robert L. Tokar
土卫二的羽流是一个显著的等离子体环境，包含几种带电粒子。其中包括冷磁层电子、正负水团簇、带电纳米颗粒以及土卫二附近整个磁层中性粒子电离产生的“磁层光电子”。在这里，我们讨论的人口新确定的卡西尼等离子体光谱仪（CAPS）电子光谱仪仪器在羽流电离层本身产生的光电子的意见。这些是在E19遭遇期间发现的，在没有穿透粒子的高能粒子阴影中。在整个E19中，CAPS取向为远离冲压方向，其中在其他遭遇期间观察到簇和纳米颗粒。羽流光电子在E9遭遇期间也被清楚地观察到，并且在所有其他可获得电子光谱的土卫二遭遇中也被观察到。这个新的群体，比周围的等离子体人口温暖，是不同的，但增加了，磁层光电子。在这里，我们讨论的意见，并检查的影响，包括电离源这些电子提供。
The plume of Enceladus is a remarkable plasma environment containing several charged particle species. These include cold magnetospheric electrons, negative and positive water clusters, charged nanograins, and “magnetospheric photoelectrons” produced from ionization of neutrals throughout the magnetosphere near Enceladus. Here we discuss observations of a population newly identified by the Cassini Plasma Spectrometer (CAPS) electron spectrometer instrument—photoelectrons produced in the plume ionosphere itself. These were found during the E19 encounter, in the energetic particle shadow where penetrating particles are absent. Throughout E19, CAPS was oriented away from the ram direction where the clusters and nanograins are observed during other encounters. Plume photoelectrons are also clearly observed during the E9 encounter and are also seen at all other Enceladus encounters where electron spectra are available. This new population, warmer than the ambient plasma population, is distinct from, but adds to, the magnetospheric photoelectrons. Here we discuss the observations and examine the implications, including the ionization source these electrons provide.