Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Trapped radiations of saturn and their absorption by Satellites and rings

Journal Article · · J. Geophys. Res.; (United States)

The Pioneer 11 spacecraft encounter with Saturn (closest approach September 1,1979) has resulted in the discovery of a fully developed magnetosphere with high-energy trapped radiation around Saturn, as reported in Science, 207, 400--453, 1980, by several investigators with charged-particle instruments on the spacecraft. The present paper contains in detail the final energetic charged-particle measurements and new observations obtained from the University of Chicago instrumentation on Pioneer 11, including the overall characteristics of the trapped electron, proton, and helium radiation, which was found to lie inside approx.20 Saturn radii (R/sub s/) from the planet, and the regions extending outward to beyond the planetary bow shocks and into the interplanetary medium. For analytical purposes we divided that magnetosphere into an inner magnetosphere (<5R/sub s/), where the intensity profiles displayed the near-axial symmetry characteriscis of the sipole magnetic field alignment with the spin axis, and an outer magnetosphere whose characteristic on the sunward side inbound were significantly different from the dawn side out-bound, indicative of a possible magnetotial but with no dramatic evidence in the charged-particle data for an equatorial current sheet, as observed at Jupiter. The intensities and energy ranges of the protons and electrons were intermediate between the levels found previously at Jupiter by Pioneer 10 and 11 and at earth. Each spectra for protons and electrons and relative abundances of protons and helium nuclei are presented along with the average characteristics of particle anisotropies. At the time of encounter the magnetosphere was immersed in intense fluxes of electrons, protons, and helium nuclei of solar flare origin which are shown to penetrate from 1 R/sub s/ to 1 10 R/sub s/ into the magnetosphere, where they dominated the flux levels in the far outer magnetosphere.

Research Organization:
Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637
OSTI ID:
6734768
Journal Information:
J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 85:A11; ISSN JGREA
Country of Publication:
United States
Language:
English