Serial optical observation of Jovian plasma processes at the summit of Mauna Kea in Hawaii

本研究采用± 20 Rj（窄视场; Rj：木星半径）和± 400 Rj（宽视场）两种视场，对作为同位素示踪剂的钠原子D线发射分布进行了二维成像观测。根据观测结果，得到了以下发射分布特征。在窄FOV观察中，同时观察到延伸到1020 Rj的两种不同类型的分布，即带状分布和喷雾状分布。在宽视场观测中，观测到沿赤道面延伸至沿着400 Rj的细长椭圆状发射分布。根据观测到的图像，我们进行了模型分析，研究了钠原子的供应过程和钠分布的时间变化，提出了一种综合源过程，它能一致地再现窄视场观测和宽视场观测的观测特征结果表明，这种带状分布是分子离子破坏过程的结果，分子离子的典型回旋速度估计为20 km/sec.研究还表明，喷雾状分布是通过电荷交换过程产生的。然后，这两个过程的组合进行了检查的宽FOV的观测结果。组合模型分析可以很好地再现所观察到的广泛扩展的钠分布的特征。在模型分析的过程中，提出了一些重要的物理过程和有关参数。

The study, 2-dimensional imaging observations of the D-line emission distribution of logenic sodium atoms, which is regarded as a tracer of logenic volcanic gases, were performed with two field of views (FOV), namely±20Rj (narrow FOV ; Rj : Jovian radius), and ±400Rj (wide FOV). From the observational results, the following characteristics of emission distribution were obtained. In the narrow FOV observation, two different types of distribution extending to〜20Rj, that is, the band-shaped distribution and the spray-shaped distribution, were observed simultaneously. In the wide FOV observation, the elongated oval-like emission distribution extended to as much as 400Rj along the equatorial plane was observed. The east-west intensity asymmetry was also observed, with a dependence on the Io phase angle.Based on the observed images , we then made model analyses to investigate supply processes of sodium atoms and time variation of sodium distribution, and presented the comprehensive source process which can consistently reproduce the observed characteristics both in the narrow and wide FOV observation.From the model analysis for the narrow FOV observational results, it is concluded that the band-shaped distribution is attributed to the molecular ion destruction process, and the typical gyrovelocity of the molecular ions is estimated to be 20km/sec. It is also concluded that the spray-shaped distribution is produced through the charge exchange process. Then a combination of the two processes was examined for the wide FOV observational results. The combined model analysis could fairly reproduce the observed features of the wide extended sodium distribution. In the course of the model analysis, some important physical processes and related parameters are suggested.