Composition and dynamics of plasma in Saturn's magnetosphere.
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.
Young
D T
DT
Southwest Research Institute, San Antonio, TX 78238, USA. dyoung@swri.edu
Berthelier
J-J
JJ
Blanc
M
M
Burch
J L
JL
Bolton
S
S
Coates
A J
AJ
Crary
F J
FJ
Goldstein
R
R
Grande
M
M
Hill
T W
TW
Johnson
R E
RE
Baragiola
R A
RA
Kelha
V
V
McComas
D J
DJ
Mursula
K
K
Sittler
E C
EC
Svenes
K R
KR
Szegö
K
K
Tanskanen
P
P
Thomsen
M F
MF
Bakshi
S
S
Barraclough
B L
BL
Bebesi
Z
Z
Delapp
D
D
Dunlop
M W
MW
Gosling
J T
JT
Furman
J D
JD
Gilbert
L K
LK
Glenn
D
D
Holmlund
C
C
Illiano
J-M
JM
Lewis
G R
GR
Linder
D R
DR
Maurice
S
S
McAndrews
H J
HJ
Narheim
B T
BT
Pallier
E
E
Reisenfeld
D
D
Rymer
A M
AM
Smith
H T
HT
Tokar
R L
RL
Vilppola
J
J
Zinsmeyer
C
C
D001272:Atmosphere; D005118:Extraterrestrial Environment; D006859:Hydrogen; D007053:Ice; D007477:Ions; D008280:Magnetics; D010100:Oxygen; D011522:Protons; D018539:Saturn; D018531:Spacecraft; D013057:Spectrum Analysis
D007053:Ice; D007477:Ions; D011522:Protons; D006859:Hydrogen; D010100:Oxygen