Increasing positive ion number densities below the peak of ion-electron pair production in titan's ionosphere

E. Vigren, M. Galand, O. Shebanits, J. E. Wahlund, W. D. Geppert, P. Lavvas, V. Vuitton, R. V. Yelle

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

We combine derived ion-electron pair formation rates with Cassini Radio Plasma Wave Science Langmuir Probe measurements of electron and positive ion number densities in Titan's sunlit ionosphere. We show that positive ion number densities in Titan's sunlit ionosphere can increase toward significantly lower altitudes than the peak of ion-electron pair formation despite that the effective ion-electron recombination coefficient increases. This is explained by the increased mixing ratios of negative ions, which are formed by electron attachment to neutrals. While such a process acts as a sink for free electrons, the positive ions become longer-lived as the rate coefficients for ion-anion neutralization reactions are smaller than those for ion-electron dissociative recombination reactions.

Original languageEnglish (US)
Article number69
JournalAstrophysical Journal
Volume786
Issue number1
DOIs
StatePublished - May 1 2014

Keywords

  • molecular processes
  • planets and satellites: individual (Titan)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'Increasing positive ion number densities below the peak of ion-electron pair production in titan's ionosphere'. Together they form a unique fingerprint.

  • Cite this