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Jupiter's internal magnetic field geometry relevant to particle trapping


  • Juan G. Roederer,

  • Mario H. Acuña,

  • Norman F. Ness


The internal magnetic field model of Acuña and Ness (1976a) has been used to compute trapped particle drift shells and other field-invariant characteristics relevant to Jupiter's radiation belts and their interaction with the planetary ionosphere. The traces in invariant coordinate space (for instance, equatorial pitch angle and L value) scanned during spacecraft rotation by directional particle detectors on Pioneer 10 and 11 have been determined for the trajectory portions lying within 10 RJ; this corresponds to the inner magnetosphere of Jupiter, where contributions of external magnetic field sources are expected to be very small. These plots can be used conveniently to separate pitch angle distribution effects from radial dependence effects. Drift shell intersections with the planet and associated particle precipitation functions have been computed. Possible correlations with decametric radio emissions are discussed. The influence of the internal field asymmetry on ionospheric plasma escape is computed and analyzed. It is found that the latitude dependence of the plasma escape function should have a decisive influence on the longitudinal asymmetry of the corotating plasma if the ionosphere is the principal source of magnetospheric plasma.

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