Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 29, 187-195, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
24 Jan 2011
Comprehensive calculation of the energy per ion pair or W values for five major planetary upper atmospheres
C. Simon Wedlund1, G. Gronoff2, J. Lilensten3, H. Ménager3, and M. Barthélemy3 1Belgian Institute for Space Aeronomy, BIRA-IASB, Brussels, Belgium
2NASA Langley Research Center, Hampton, VA, USA
3Institut de Planétologie et d'Astrophysique de Grenoble, IPAG, Grenoble, France
Abstract. The mean energy W expended in a collision of electrons with atmospheric gases is a useful parameter for fast aeronomy computations. Computing this parameter in transport kinetic models with experimental values can tell us more about the number of processes that have to be taken into account and the uncertainties of the models. We present here computations for several atmospheric gases of planetological interest (CO2, CO, N2, O2, O, CH4, H, He) using a family of multi-stream kinetic transport codes. Results for complete atmospheres for Venus, Earth, Mars, Jupiter and Titan are also shown for the first time. A simple method is derived to calculate W of gas mixtures from single-component gases and is conclusively checked against the W values of these planetary atmospheres. Discrepancies between experimental and theoretical values show where improvements can be made in the measurement of excitation and dissociation cross-sections of specific neutral species, such as CO2 and CO.

Citation: Simon Wedlund, C., Gronoff, G., Lilensten, J., Ménager, H., and Barthélemy, M.: Comprehensive calculation of the energy per ion pair or W values for five major planetary upper atmospheres, Ann. Geophys., 29, 187-195,, 2011.
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