A comparison of the radio data and model calculations of Jupiter's synchrotron radiation, 1. The high energy electron distribution in Jupiter's inner magnetosphere

Abstract

An electron distribution in Jupiter's magnetosphere as a function of energy, pitch angle and spatial coordinates is derived from a comparison of model calculations of the planet's synchrotron radiation with the radio data; the distribution is consistent with the information available from the Pioneer data. The model calculations are based upon the magnetic field configurations as derived by Acuna and Ness [1976a, b] (the O4 model) and Davis, Jones and Smith [quoted in Smith and Gulkis, 1979] (the P11 (3,2) A model) from the Pioneer data. The electrons are assumed to diffuse radially inwards with a rate D=3 × 10−9 L³ s−1 (where L is McIlwain's value) and have a lifetime against local losses τ=4 × 106 L−0.6 s, in agreement with the values derived by Goertz et al. [1979] from the Pioneer data. The number density of electrons with E ≥20 MeV at L=3 is in agreement with the values measured by the spacecraft, but the energy distribution appears to be much flatter. Electrons are absorbed with survival probabilities of ∼0.5 diffusing inwardly past Amalthea's sweeping region (for 20‐MeV electrons) and ∼0.35 past the ring, respectively. An energy dependent pitch angle scattering is found to occur at Amalthea's orbit, and there is no pitch angle scattering present near the ring.