title: Triton:  topside ionosphere and nitrogen escape.
abstract: The principal ion in the ionosphere of Triton is N+.  Energetic electrons of magnetospheric origin are the primary source of ionization, with a smaller contribution due to photoionization.  To explain the topside plasma scale height, we postulate that N+ ions escape from Triton.  The loss rate is 3.4 x 10(7) cm-2 s-1 or 7.9 x 10(24) ions s-1.  Dissociative recombination of N2+ produces neutral exothermic fragments that can escape from Triton.  The rate is estimated to be 8.6 x 10(6) N cm-2 s-1 or 2.0 x 10(24) atoms s-1.  Implications for the magnetosphere of Neptune and Triton's evolution are discussed.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, USA.
authors.forename: Y L
authors.initials: YL
authors.lastname: Yung
authors.forename: J R
authors.initials: JR
authors.lastname: Lyons
mesh_terms: D001272:Atmosphere; D004583:Electrons; D005118:Extraterrestrial Environment; D006859:Hydrogen / Q000032:analysis; D007477:Ions; D008697:Methane / Q000032:analysis; D008956:Models, Chemical; D018541:Neptune; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry; D010777:Photochemistry; D017785:Photons
chemical_list: D007477:Ions; D006859:Hydrogen; D009584:Nitrogen; D008697:Methane