Energetic oxygen and sulfur ions in the Jovian magnetosphere

Technical Report · Thu Jan 01 04:00:00 EST 1981

OSTI ID:5652213

Gehrels, N

Observations of 1 to 20 MeV/nuc oxygen, sodium, and sulfur ions in the Jovian magnetosphere are reported. Measurements made by the cosmic ray subsystem on Voyager 1 and 2 were used to calculate abundances and energy spectra in the region from 5 to 20 Jovian radii. The phase space density of the oxygen ions calculated from the spectra has a positive radial gradient between 6 and 17 Jovian radii, indicating an inward diffusive flow. The diffusion coefficient upper limit at 9 Jovian radii is approximately 10 to the -5 power/s. This limit, combined with the analysis of Voyager plasma observations by Siscoe et al.1981, implies an upper limit to the mass loading rate near Io of approximately 10 to the 28th power ions/s. The energetic oxygen lifetime is within an order of magnitude of the strong pitch-angle diffusion lifetime in this region, with the largest total number of particles lost between 7.5 and 12.5 Jovian radii. It is shown that the losses are not due to geometric absorption by Io, absorption by dust grains, or energy loss in the plasma of the inner magnetosphere, and it is therefore postulated that the primary loss mechanism is pitch-angle scattering into the loss cone.

• Research Organization: California Inst. of Tech., Pasadena (USA)
• OSTI ID: 5652213
• Report Number(s): NASA-CR-164860
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHALCOGENIDES
CHEMICAL COMPOSITION
JUPITER PLANET
OXIDES
OXYGEN COMPOUNDS
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
SPACE VEHICLES
SULFUR COMPOUNDS
SULFUR OXIDES
VEHICLES
VOYAGER SPACE PROBES