Discovery of heavy negative ions in Titan's ionosphere
Article first published online: 28 NOV 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 22, November 2007
How to Cite
2007), Discovery of heavy negative ions in Titan's ionosphere, Geophys. Res. Lett., 34, L22103, doi:10.1029/2007GL030978., , , , , and (
- Issue published online: 28 NOV 2007
- Article first published online: 28 NOV 2007
- Manuscript Accepted: 19 OCT 2007
- Manuscript Revised: 11 OCT 2007
- Manuscript Received: 21 JUN 2007
- negative ions;
 Titan's ionosphere contains a rich positive ion population including organic molecules. Here, using CAPS electron spectrometer data from sixteen Titan encounters, we reveal the existence of negative ions. These ions, with densities up to ∼100 cm−3, are in mass groups of 10–30, 30–50, 50–80, 80–110, 110–200 and 200+ amu/charge. During one low encounter, negative ions with mass per charge as high as 10,000 amu/q are seen. Due to their unexpectedly high densities at ∼950 km altitude, these negative ions must play a key role in the ion chemistry and they may be important in the formation of organic-rich aerosols (tholins) eventually falling to the surface.