期刊
PLANETARY AND SPACE SCIENCE
卷 57, 期 14-15, 页码 1743-1753出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.pss.2009.04.014
关键词
Saturn; Magnetosphere; Cassini; UVIS
The intensity of H Ly alpha 1216A (P-2-S-1) and OI 1304 angstrom (2p(3)3s(3)S-2p(43)P) is mapped in the magnetosphere of Saturn using the ultraviolet imaging spectrograph (UVIS) [Esposito, L.W., Barth, C.A., Colwell, J.E., Lawrence, G.M., McClintock, W.E., Stewart, A.I.F., Keller, H.U., Korth, A., Lauche, H., Festou M.C. Lane,,, A.L., Hansen, C.J., Maki, J.N., West, R.A., Jahn, H., Reulke, R., Warlich, K., Shemansky, D.E., Yung, Y.L., 2004. The Cassini ultraviolet imaging spectrograph investigation. Space Science Reviews 115, 299-3611 onboard Cassini. Spatial coverage is built up by stepping the slit sequentially across the system (system scan). Data are obtained at a large range of space-craft-Saturn distances. The observed atomic hydrogen distribution is very broad, extending beyond 40R(S) in the equatorial plane, with the intensity increasing with decreasing distances to Saturn. The distribution displays persistent local-time asymmetries, and is seen connecting continuously to the upper atmosphere of the planet at sub-solar latitudes located well outside of the equatorial (ring) plane. This is consistent with the source of the atomic hydrogen being located at the top of the atmosphere on the sun-lit side of the planet on the southern hemisphere. In addition there are a number of temporally persistent features in the intensity distribution, indicating a complex hydrogen energy distribution. The emission from OI 1304 angstrom is generally distributed as a broad torus centered around similar to 4R(S) although the position of the peak intensity can vary by as much as +/-1R(S). There is significant intensity present out to +/-10R(S). HST observations of hydroxyl (CH) are re-analyzed and display a distribution half as broad as that of oxygen, also centered at 4R(S). The observed atomic oxygen distribution requires a sourcing of 1.3 x 10(28) atoms s(-1) against loss due to charge capture with the plasma. Using the ion partitioning of Schippers et al. [2008. Multi-instrument analysis of electron Populations in Saturn's magnetosphere. journal of Geophysical Research (Space Physics) 113 (A12) 7208-+] then recombination of H2O+ and H3O+ Will account for about a quarter of the mass-loss in the inner magnetosphere, with charge capture of O+ accounting for the rest. The oxygen loss rate is seen to vary by 2 x 10(27) atoms s(-1) over periods of weeks. (C) 2009 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据