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Plasmas in Saturn's magnetosphereThe solar wind plasma analyzer on board Pioneer 2 provides first observations of low-energy positive ions in the magnetosphere of Saturn. Measurable intensities of ions within the energy-per-unit charge (E/Q) range 100 eV to 8 keV are present over the planetocentric radial distance range about 4 to 16 R sub S in the dayside magnetosphere. The plasmas are found to be rigidly corotating with the planet out to distances of at least 10 R sub S. At radial distances beyond 10 R sub S, the bulk flows appear to be in the corotation direction but with lesser speeds than those expected from rigid corotation. At radial distances beyond the orbit of Rhea at 8.8 R sub S, the dominant ions are most likely protons and the corresponding typical densities and temperatures are 0.5/cu cm and 1,000,000 K, respectively, with substantial fluctuations. It is concluded that the most likely source of these plasmas in the photodissociation of water frost on the surface of the ring material with subsequent ionization of the products and radially outward diffusion. The presence of this plasma torus is expected to have a large influence on the dynamics of Saturn's magnetosphere since the pressure ratio beta of these plasmas approaches unity at radial distances as close to the planet as 6.5 R sub S. On the basis of these observational evidences it is anticipated that quasi-periodic outward flows of plasma, accompanied with a reconfiguration of the magnetosphere beyond about 6.5 R sub S, will occur in the local night sector in order to relieve the plasma pressure from accretion of plasma from the rings.
Document ID
19810013460
Acquisition Source
Legacy CDMS
Document Type
Preprint (Draft being sent to journal)
Authors
Frank, L. A. (Iowa Univ. Iowa City, IA, United States)
Burek, B. G. (Iowa Univ. Iowa City, IA, United States)
Ackerson, K. L. (Iowa Univ. Iowa City, IA, United States)
Wolfe, J. H. (NASA Ames Research Center)
Mihalov, J. D. (NASA Ames Research Center)
Date Acquired
September 4, 2013
Publication Date
April 1, 1980
Subject Category
Lunar And Planetary Exploration
Report/Patent Number
AD-A096079
U-OF-IOWA-80-12
Accession Number
81N21990
Funding Number(s)
CONTRACT_GRANT: NGL-16-001-002
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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