Influence of local ionization on ionospheric densities in Titan's upper atmosphere
文献类型：期刊论文
| 作者 | Sagnieres, Luc B. M.1; Galand, Marina1; Cui, Jun2 ; Lavvas, Panayotis P.3; Vigren, Erik4; Vuitton, Veronique5; Yelle, Roger V.6; Wellbrock, Anne7; Coates, Andrew J.7
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| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
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| 出版日期 | 2015-07-01 |
| 卷号 | 120期号:7页码:5899-5921 |
| 关键词 | Titan ionization processes Cassini upper atmosphere |
| 英文摘要 | Titan has the most chemically complex ionosphere of the solar system. The main sources of ions on the dayside are ionization by EUV solar radiation and on the nightside include ionization by precipitated electrons from Saturn's magnetosphere and transport of ions from the dayside, but many questions remain open. How well do models predict local ionization rates? How strongly do the ionization processes drive the ionospheric densities locally? To address these questions, we have carried out an analysis of ion densities from the Ion and Neutral Mass Spectrometer (INMS) from 16 close flybys of Titan's upper atmosphere. Using a simple chemical model applied to the INMS data set, we have calculated the ion production rates and local ionization frequencies associated with primary ions and . We find that on the dayside the solar energy deposition model overestimates the INMS-derived production rates by a factor of 2. On the nightside, however, the model driven by suprathermal electron intensities from the Cassini Plasma Spectrometer Electron Spectrometer sometimes agrees and other times underestimates the INMS-derived production rates by a factor of up to 2-3. We find that below 1200km, all ion number densities correlate with the local ionization frequency, although the correlation is significantly stronger for short-lived ions than long-lived ions. Furthermore, we find that, for a given N-2 local ionization frequency, has higher densities on the dayside than on the nightside. We explain that this is due to CH4 being more efficiently ionized by solar photons than by magnetospheric electrons for a given amount of N-2 ionization. |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000360381400049 |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/5625]  |
| 专题 | 国家天文台_月球与深空探测研究部 |
| 作者单位 | 1.Univ London Imperial Coll Sci Technol & Med, Dept Phys, London, England 2.Chinese Acad Sci, Natl Astron Observ, Key Lab Lunar & Deep Space Explorat, Beijing, Peoples R China 3.Univ Reims, Grp Spectrometrie Mol & Atmospher, Reims, France 4.Swedish Inst Space Phys, Uppsala, Sweden 5.Inst Planetol & Astrophys Grenoble, Grenoble, France 6.Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA 7.Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England |
| 推荐引用方式 GB/T 7714 | Sagnieres, Luc B. M.,Galand, Marina,Cui, Jun,et al. Influence of local ionization on ionospheric densities in Titan's upper atmosphere[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,2015,120(7):5899-5921. |
| APA | Sagnieres, Luc B. M..,Galand, Marina.,Cui, Jun.,Lavvas, Panayotis P..,Vigren, Erik.,...&Coates, Andrew J..(2015).Influence of local ionization on ionospheric densities in Titan's upper atmosphere.JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,120(7),5899-5921. |
| MLA | Sagnieres, Luc B. M.,et al."Influence of local ionization on ionospheric densities in Titan's upper atmosphere".JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 120.7(2015):5899-5921. |
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来源：国家天文台
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