Influence of local ionization on ionospheric densities in Titan's upper atmosphere
Influence of local ionization on ionospheric densities in Titan's upper atmosphere
复制标题
局部电离对泰坦高层大气电离层密度的影响
DOI：
10.1002/2014ja020890
复制
发表时间：
2015-07
影响因子：
2.8
通讯作者：
Coates Andrew J.
中科院分区：
文献类型：
--
作者：
Sagnieres Luc B. M.;Gal;Marina;Cui Jun;Lavvas Panayotis P.;Vigren Erik;Vuitton Veronique;Yelle Roger V.;Wellbrock Anne;Coates Andrew J.
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 N2+ and CH4+ . We find that on the dayside the solar energy deposition model overestimates the INMS‐derived N2+ 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 N2+ production rates by a factor of up to 2–3. We find that below 1200 km, 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 N2 local ionization frequency, CH5+ 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 N2 ionization.
登录
查看更多内容
影响因子：
--
作者：
V. Vuitton;R. Yelle;J. Cui
通讯作者：
V. Vuitton;R. Yelle;J. Cui
影响因子：
3.2
作者：
Cui, J.;Yelle, R. V.;Magee, B. A.
通讯作者：
Magee, B. A.
DOI：
10.1006/icar.1997.5831
发表时间：
1995-06
期刊：
--
影响因子：
--
作者：
M. Bird;R. Dutta-Roy;S. Asmar;T. Rebold
通讯作者：
M. Bird;R. Dutta-Roy;S. Asmar;T. Rebold
影响因子：
2.4
作者：
K. Ågren;J. Wahlund;P. Garnier;R. Modolo;J. Cui;M. Galand;I. Müller-Wodarg
通讯作者：
K. Ågren;J. Wahlund;P. Garnier;R. Modolo;J. Cui;M. Galand;I. Müller-Wodarg
影响因子：
5.2
作者：
A. Wellbrock;A. Coates;G. Jones;G. Lewis;J. Waite
通讯作者：
A. Wellbrock;A. Coates;G. Jones;G. Lewis;J. Waite