Voyager 1: Energetic Ions and Electrons in the Jovian Magnetosphere

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Science  01 Jun 1979:
Vol. 204, Issue 4396, pp. 1003-1007
DOI: 10.1126/science.204.4396.1003


The observations of the cosmic-ray subsystem have added significantly to our knowledge of Jupiter's magnetosphere. The most surprising result is the existence of energetic sulfur, sodium, and oxygen nuclei with energies above 7 megaelectron volts per nucleon which were found inside of Io's orbit. Also, significant fluxes of similarly energetic ions reflecting solar cosmic-ray composition were observed throughout the magnetosphere beyond 11 times the radius of Jupiter. It was also found that energetic protons are enhanced by 30 to 70 percent in the active hemisphere. Finally, the first observations were made of the magnetospheric tail in the dawn direction out to 160 Jupiter radii.