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Prediction of a N 2 ++ layer in the upper atmosphere of Titan
Author(s) -
Lilensten J.,
Witasse O.,
Simon C.,
SoldiLose H.,
Dutuit O.,
Thissen R.,
Alcaraz C.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl021432
Subject(s) - dissociative recombination , titan (rocket family) , ion , atmosphere of titan , dication , atomic physics , metastability , electron , atmosphere (unit) , physics , electron density , atmospheric escape , materials science , analytical chemistry (journal) , astrobiology , chemistry , nuclear physics , meteorology , recombination , biochemistry , quantum mechanics , gene , mars exploration program , chromatography
Calculations of dication N 2 ++ density in the atmosphere of Titan is performed for the first time. The metastable lifetime of this species is 3 seconds in its ground state. The density of the N 2 ++ layer centred around 1100–1200 km altitude can reach 10 4 m −3 . The ions are produced by both the double photoionisation and the photoelectron impact of N 2 . They are lost by dissociative recombination with the thermal electrons and chemical reactions with N 2 and CH 4 . The most recent chemical reaction rate constants, given by laboratory experiments, were used in this study. Finally, we explore the possible detection of this ion layer by a spectrophotometer and show that the UVIS instrument onboard CASSINI could be capable to observe it.