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G.J. Molina-Cuberos (IAA-CSIC and IWF-\"OAW), J.J. L\'opez-Moreno, R. Rodrigo (IAA-CSIC), K Schwingenschuh (IWF-\"OAW)
The lower ionosphere of Titan (from 1 to 400 km) has been described by a new one-dimensional chemistry model. Cosmic rays have the highest penetrating power of the likely ionization sources in Titan's atmosphere. Cosmic rays can reach Titan's troposphere and ionize the neutral atmospheric species (mainly N2, CH4, H2 and CO) to produce an ionosphere comparable in magnitude to that resulting from solar EUV radiation and Saturn's electrons at higher altitude. The model considers the most recent knowledge of the atmosphere of Titan and includes, until now, the largest number of ion-neutral reaction rates applied to its lower ionosphere. We have calculated the ion and electron density profiles and the influence of solar activity, dissociative recombination rate, the nature of the most abundant species, and the existence of an intrinsic magnetic field on the concentration of electrons. An analysis of the model's sensitivity to changes of the rate coefficient and of the neutral composition has also been realized in this model. We also investigate the influence of electrophilic species on the concentration of cations, anions and electrons.
This work has been funded by CICYT in the frame of the research program ESP96-0623. Thanks also to IWF for funding the DPS assistance. G.J. M-C thanks the SEUI-MEC for research fellowships.
The author(s) of this abstract have provided an email address for comments about the abstract: molina@iwf.tu-graz.ac.at