Hot electron component in the lo plasma torus confirmed through EUV spectral analysis
Hot electron component in the lo plasma torus confirmed through EUV spectral analysis
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通过 EUV 光谱分析证实等离子体环中的热电子成分
DOI：
10.1029/2011ja016583
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
et al
中科院分区：
文献类型：
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作者：
K.Yoshioka;et al
Io等离子体环主要由硫和氧离子及其化合物以及电子背景组成。除了这些基本成分，几个现场观测显示，那里的一小部分电子被激发到比背景电子高100倍的温度。它们对木星内部磁层的能量平衡有重大影响。然而，它们的生成过程尚未得到澄清。一个困难是，现有的关于超热电子的数据都来自现场观测，不能明确地探索时空分布。因此，为了弄清超热电子问题，需要能够直接了解等离子体动力学的遥感技术。在这项研究中，一种等离子体诊断方法被用于从卡西尼号航天器上获取的Io等离子体环EUV光谱。与以前的观测结果一致，证实了由我们的模型确定的背景电子温度和离子组成。此外，当模型采用超热电子元件运行时，可用数据的匹配性更好。这一通过遥感得到的一致证实是第一次。由于时间分辨率和观测覆盖范围的限制，这些结果不能用来解释超热电子的产生过程。然而，我们预计，当来自未来飞行任务的更好的时间分辨率和更完整的覆盖范围的数据可用时，这种方法将有助于研究热电子的产生过程。
The Io plasma torus is composed mainly of sulfur and oxygen ions and their compounds, together with a background of electrons. In addition to those basic components, several in situ observations have shown that a small percentage of the electrons there have been excited to be as much as 100 times hotter than the background electrons. They have a significant impact on the energy balance in the Jovian inner magnetosphere. However, their generation process has not yet been clarified. One difficulty is that the available data about the hot electrons all come from in situ observations which cannot explore the temporal and spatial distributions explicitly. Therefore, remote sensing which can take a direct picture of the plasma dynamics is necessary in order to clarify the hot electron problem. In this study, a plasma diagnosis method was used for the Io plasma torus EUV spectra taken from the Cassini spacecraft. Agreement with previous observations confirmed the background electron temperature and ion compositions as determined by our model. In addition, the available data are matched even better when the model is run with a hot electron component. This consistent confirmation by remote sensing is a first. Because of the limited temporal resolution and observational coverage, the results could not be used to explain the generation process of the hot electrons. However, we expect that this method will be useful in studying the hot electron generation process when data from future missions with better temporal resolution and more complete coverage become available.