title: Composition and dynamics of plasma in Saturn's magnetosphere.
abstract: During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede.
authors.affiliation: Southwest Research Institute, San Antonio, TX 78238, USA. dyoung@swri.edu
authors.forename: D T
authors.initials: DT
authors.lastname: Young
authors.forename: J-J
authors.initials: JJ
authors.lastname: Berthelier
authors.forename: M
authors.initials: M
authors.lastname: Blanc
authors.forename: J L
authors.initials: JL
authors.lastname: Burch
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authors.initials: S
authors.lastname: Bolton
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authors.initials: FJ
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authors.lastname: Goldstein
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authors.lastname: Grande
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authors.lastname: Hill
authors.forename: R E
authors.initials: RE
authors.lastname: Johnson
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authors.lastname: Baragiola
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authors.lastname: Kelha
authors.forename: D J
authors.initials: DJ
authors.lastname: McComas
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authors.lastname: Mursula
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authors.initials: EC
authors.lastname: Sittler
authors.forename: K R
authors.initials: KR
authors.lastname: Svenes
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authors.initials: K
authors.lastname: Szegö
authors.forename: P
authors.initials: P
authors.lastname: Tanskanen
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authors.initials: MF
authors.lastname: Thomsen
authors.forename: S
authors.initials: S
authors.lastname: Bakshi
authors.forename: B L
authors.initials: BL
authors.lastname: Barraclough
authors.forename: Z
authors.initials: Z
authors.lastname: Bebesi
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authors.initials: D
authors.lastname: Delapp
authors.forename: M W
authors.initials: MW
authors.lastname: Dunlop
authors.forename: J T
authors.initials: JT
authors.lastname: Gosling
authors.forename: J D
authors.initials: JD
authors.lastname: Furman
authors.forename: L K
authors.initials: LK
authors.lastname: Gilbert
authors.forename: D
authors.initials: D
authors.lastname: Glenn
authors.forename: C
authors.initials: C
authors.lastname: Holmlund
authors.forename: J-M
authors.initials: JM
authors.lastname: Illiano
authors.forename: G R
authors.initials: GR
authors.lastname: Lewis
authors.forename: D R
authors.initials: DR
authors.lastname: Linder
authors.forename: S
authors.initials: S
authors.lastname: Maurice
authors.forename: H J
authors.initials: HJ
authors.lastname: McAndrews
authors.forename: B T
authors.initials: BT
authors.lastname: Narheim
authors.forename: E
authors.initials: E
authors.lastname: Pallier
authors.forename: D
authors.initials: D
authors.lastname: Reisenfeld
authors.forename: A M
authors.initials: AM
authors.lastname: Rymer
authors.forename: H T
authors.initials: HT
authors.lastname: Smith
authors.forename: R L
authors.initials: RL
authors.lastname: Tokar
authors.forename: J
authors.initials: J
authors.lastname: Vilppola
authors.forename: C
authors.initials: C
authors.lastname: Zinsmeyer
mesh_terms: D001272:Atmosphere; D005118:Extraterrestrial Environment; D006859:Hydrogen; D007053:Ice; D007477:Ions; D008280:Magnetics; D010100:Oxygen; D011522:Protons; D018539:Saturn; D018531:Spacecraft; D013057:Spectrum Analysis
chemical_list: D007053:Ice; D007477:Ions; D011522:Protons; D006859:Hydrogen; D010100:Oxygen