Ionospheric photoelectrons at Venus: Initial observations by ASPERA-4 ELS
- 作者：A.J. Coates ; R.A. Frahm ; D.R. Linder ; D.O. Kataria ; Y. Soobiah ; G. Collinson ; J.R. Sharber ; J.D. Winningham ; S.J. Jeffers ; S. Barabash ; J.-A. Sauvaud ; R. Lundin ; M. Holmströ ; m ; Y. Futaana ; M. Yama
- 关键词：Venus ; Plasma ; lonosphere
- 刊名：Planetary and Space Science
- 出版年：2008
- 期刊代码：60_00320633
- 类别：ph
- 出版时间：May 2008
- 卷：56
- 期：6
- 页码：802-806
- 文件大小：478 K
摘要
We report the detection of electrons due to photo-ionization of atomic oxygen and carbon dioxide in the Venus atmosphere by solar helium 30.4 nm photons. The detection was by the Analyzer of Space Plasma and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) on the Venus Express (VEx) European Space Agency (ESA) mission. Characteristic peaks in energy for such photoelectrons have been predicted by Venus atmosphere/ionosphere models. The ELS energy resolution (ΔE/E![]()
src="http://www.sciencedirect.com/scidirimg/entities/223c.gif" alt="not, vert, similar" title="not, vert, similar" border="0">7%) means that these are the first detailed measurements of such electrons. Considerations of ion production and transport in the atmosphere of Venus suggest that the observed photoelectron peaks are due primarily to ionization of atomic oxygen.