Overview of the Voyager ultraviolet spectrometry results through Jupiter encounter
Overview of the Voyager ultraviolet spectrometry results through Jupiter encounter
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航海者号遭遇木星的紫外光谱测量结果概述
DOI：
10.1029/ja086ia10p08259
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发表时间：
1981
影响因子：
--
通讯作者：
J. Bertaux
中科院分区：
文献类型：
--
作者：
A. Broadfoot;B. Sandel;D. Shemansky;J. McConnell;Gerald R. Smith;J. Holberg;S. Atreya;T. Donahue;D. Strobel;J. Bertaux
自1977年发射以来，旅行者紫外线光谱仪(UVS)几乎一直在500-A到1700-A波长范围内对太阳系和银河系的光源进行连续观测。由于它们的灵敏度、稳定性和动态范围，这些光谱仪已经在木星系统、星际介质、天文和天体物理源方面取得了惊人的发现。这些结果最令人惊讶的总体方面是观察到了各种各样的排放过程和物种。在木星的圆盘上，迄今探测到的辐射是H-莱曼α、H-莱曼β、He(584A)以及H2-莱曼和沃纳波段。原子发射是由太阳光的共振散射激发的，而氢带似乎是由粒子沉淀激发的。在夜盘上，只有H莱曼α在场。木星的极光区域清楚地被这颗行星白天和晚上强烈发射的H和H2波段所勾勒出来。氦的发射也存在于极光区域。在木星上，大气也通过太阳和恒星掩星实验进行了探测。太阳掩星揭示了高层大气中H2和H的分布，而恒星掩星揭示了上层中间层和下层热层的结构。目前的分析表明，涡旋扩散系数为∼106 cm2 S−1，中层温度为∼200K。太阳掩星分析表明，大气层外温度为1450±300K，热层递减率为∼1K/Km。莱曼α对该圆盘的观测揭示了H的纵向不对称性，这可能反映了木星磁层的纵向不对称性。在硫离子和氧离子的跃迁中，观测到了来自Io轨道的等离子体环的强EUV发射，而钾的贡献可能很小。等离子体致密区的有效电子温度估计为8×104K，没有从Io探测到局域极紫外辐射，限制了Io对∼1027离子的质量负载S−1。离子亚种的分配偏离了纯碰撞平衡，但初步分析表明扩散损失率很低。环面的辐射冷却率为∼3×1012W。太阳系外的整个天空的出现被绘制在He(584A)和HLyα(1216A)的发射线上，这是由于进入太阳系的中性星际氢和氦对太阳线的共振散射而产生的。已在若干选定的方向上测量了漫射银河系EUV辐射。在912A测量了原子氢的莱曼极限附近的恒星光球辐射。最后，在几条发射线上获得了天鹅座环超新星残骸的光谱图像。本文各节回顾了这些课题的研究进展，以及EUV结果与其他旅行者实验的关系。我们讨论了仪器的特性和光谱分析的方法，以验证报告结果的完整性。
The Voyager ultraviolet spectrometers (UVS) have been making almost continuous observations, in the 500-A to 1700-A wavelength range, of sources in the solar system and galaxy since launch in 1977. Due to their sensitivity, stability, and dynamic range, the spectrometers have made a remarkable number of discoveries pertaining to the Jupiter system, the interstellar medium, astronomical, and astrophysical sources. The most surprising general aspect of these results has been the wide variety of emission processes and species which have been observed. On Jupiter's disc, the emissions detected to date are H Lyman α, H Lyman β, He (584 A), and the H2 Lyman and Werner bands. The atomic emissions are excited by resonance scattering of sunlight, while the H2 bands appear to be excited by particle precipitation. On the nightside disc, only H Lyman α is present. Jupiter's auroral region is clearly delineated by intense emissions of H and H2 bands on both dayside and nightside of the planet. Emission from He is also present in the auroral regions. At Jupiter, the atmosphere was also probed by means of solar and stellar occultation experiments. The solar occultation has revealed the distribution of H2 and H in the upper atmosphere, while the stellar occultation has probed the structure of the upper mesosphere and lower thermosphere. Current analysis indicates an eddy diffusion coefficient ∼106 cm² s−1 with a mesospheric temperature ∼200 K. The solar occultation analysis suggests an exospheric temperature of 1450±300 K. The thermospheric lapse rate appears to be ∼1 K/km. The Lyman α observations of the disc have revealed a longitudinal asymmetry in H which may reflect longitudinal asymmetries in Jupiter's magnetosphere. Strong EUV emission from a plasma torus at the orbit of Io has been observed in transitions of sulfur and oxygen ions with a possible small contribution from potassium. The effective electron temperature of the dense regions of the plasma is estimated to be 8 × 104 K. No localized EUV emission has been detected from Io, limiting mass loading at Io to ∼1027 ions s−1. The partitioning of ion sub-species shows deviation from pure collisional equilibrium, but preliminary analysis indicates a low diffusive loss rate. The radiative cooling rate of the torus is ∼3 × 1012 W. The appearance of the entire sky in the outer solar system has been mapped in the emission lines of He (584 A) and H Lyα (1216 A) arising from resonant scattering of the solar lines by neutral interstellar hydrogen and helium entering the solar system. Diffuse galactic EUV emission has been measured in a number of selected directions. Stellar photospheric emissions shortward of the Lyman limit of atomic hydrogen at 912 A have been measured. Finally, spectral images, in several emission lines, have been obtained of the Cygnus Loop supernova remnant. Sections of this article review the progress in the study of these subjects and the relationships of the EUV results to the other Voyager experiments. We include a discussion of the characteristics of the instrument and the methods of spectral analysis to verify the integrity of the reported results.
高能电子强烈扩散到漫射极光中
DOI：
--
发表时间：
2018
期刊：
影响因子：
--
作者：
Kasahara;S.;Y. Miyoshi;S. Yokota;Y. Kasahara;S. Matsuda;A. Kumamoto;A. Matsuoka;H. U. Frey;V. Angelopoulos;S. Kurita;K. Keika;T. Hori;I. Shinohara
通讯作者：
I. Shinohara