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| Titel |
Particle pressure, inertial force and ring current density in the magnetosphere of Saturn |
| VerfasserIn |
Nick Sergis, Stamatios Krimigis, Christopher Arridge, Edmond Roelof, Abigail Rymer, Donald Mitchell, Michelle Thomsen, Margaret Kivelson, Kate Ramer, Douglas Hamilton, Norbert Krupp, Michele Dougherty, Andrew Coates, David Young |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036824
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| Zusammenfassung |
| We present the most recent radial profiles for the thermal plasma, energetic particle and
magnetic field pressures in the equatorial magnetosphere of Saturn, as measured by the
MIMI, CAPS and MAG instruments of Cassini, currently orbiting Saturn. Data were obtained
between September 2005 and May 2006, when the spacecraft was particularly close (±0.5
RS) to the nominal magnetic equator in the range 6 to 15 RS. The radial gradient
of the total pressure is compared to the inertial body force and an average radial
profile of the azimuthal current intensity is presented. The results show that: (1) The
suprathermal (keV) pressure contribution to the total particle pressure becomes significant
outside 8-9 RS, exceeding 50% for r>12 RS. (2) The plasma beta remains above 1
outside 8 RS, reaching ~3 to ~10 between 11 and 14 RS. (3) The inertial body
force and the radial pressure gradient are similar at 9-10 RS, with the pressure
gradient prevailing beyond 11 RS. (4) The ring current develops a maximum between
~8 and 12 RS, reaching values of 100-150 pA/m2, and is primarily inertial inside
of 8.5 RS but increasingly pressure gradient-driven in its maximum region and
beyond. Farther away, it drops with radial distance much faster than the 1/r rate
that several disk current models assume. The distribution of various plasma and
energetic particle parameters in SLS phase is also examined in connection with the
observed periodicity in the radial and azimuthal components of the magnetic field. |
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