Energetic oxygen and sulfur ions in the Jovian magnetosphere and their contribution to the auroral excitation

Journal Article · Fri Jul 01 04:00:00 EDT 1983 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA088iA07p05537· OSTI ID:5811779

Gehrels, N; Stone, E C

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 are used to calculate abundances and energy spectra in the region from 5 to 20 Jovian radii (R/sub j/). The phase space density of the oxygen ins calculated from the spectra has a positive radial gradient between 6 and 17 R/sub J/, indicating an inward diffusive flow. The upper limit for the diffusion coefficient D at 9 R, is approx.10/sup -5/ s/sup -1/. This limit, combined with the analysis of Voyager plasma observations by Sisccoe et al (1981), implies an upper limit to the production rate of oxygen and sulfur ions from Io of approx.10/sup 28/ ions/s. If D(9 R/sub J/) is approx.4 x 10/sup -6/ s/sup -1/, then approx.2 x 10/sup 24/ oxygen and sulfur ions with >70 MeV/nuc-G are lost per second as they diffuse inward from 12 to 8 R/sub j/. Assuming these ions are scattered into the loss cone, they deliver approx.4 x 10/sup 12/ W to the Jovian atmosphere. Extrapolations to lower magnetic moments suggest that the 10/sup 13/-10/sup 14/ W required to produce the observed ultraviolet auroral emissins could result from the precipitation of approx.10/sup 26/ oxygen and sulfur ions/s with magnetic moments > or approx. =10 to 30 MeV/nuc-G (> or approx. =35 to 100 keV/nuc at 10 R/sub J/).

• Research Organization: California Institute of Technology, Pasadena, California 91125
• OSTI ID: 5811779
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 88:A7; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ATMOSPHERES
CHARGED PARTICLES
DIFFUSION
ENERGY SPECTRA
IONS
JUPITER PLANET
LOSS CONE
OXYGEN IONS
PLANETARY ATMOSPHERES
PLANETARY MAGNETOSPHERES
PLANETS
SODIUM IONS
SPACE VEHICLES
SPECTRA
SULFUR IONS
VEHICLES
VOYAGER SPACE PROBES