Relativistic electrons in Saturn's inner magnetosphere and an estimate of their synchrotron emission. Progress report

Energetic electron data obtained during Pioneer 11's two-way traversal of Saturn's inner magnetosphere in September 1979 are reviewed. There were substantial differences between inbound and outbound observations. The inbound data are more likely to represent the time-stationary state. A quantitative model is made for the spatial and spectral distributions of relativistic electrons. The principal features of this model are as follows: (1) The radial dependence of omnidirectional intensity J in the equatorial plane is given by J = k' exp(-1.05 x)1-EXP(-6.5 X). This distribution is applicable to the range 2.30 < or = r < or = 3.60. (2) The latitudinal dependence of J is derived from observed pitch-angle distributions. (3) As shown previously, the energy spectrum is a relatively narrow one with characteristic energies E in MeV at various r as follows: 0.69 at 5.0; 1.10 at 4.0; 1.89 at 3.0; 2.62 at 2.5; and 3.05 at 2.30. The synchrotron emission of the entire population of relativistic electrons in Saturn's inner magnetosphere is estimated to be about 1 kW with a spectral maximum at 720 kHz. It is shown that this radiation will be very difficult, if not impossible, to observe even in the near vicinity of the planet.more » This paper includes a crude but instructive explication of the truly enormous differences between the synchrotron emissions of the inner magnetospheres of Jupiter and Saturn. Indeed, this comparison was an underlying motive for undertaking the present day.« less

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