Radial Diffusion of Relativistic Electrons in Neptune's Magnetosphere

Abstract

Measurements of ≳1 MeV electrons in Neptune's magnetosphere from L ≈ 4 to 14 are well represented by solutions of a model radial diffusion equation that includes losses due to absorption by the satellite Proteus. The model provides estimates of the radial diffusion coefficient, which is 5 × 10^(−8)(L/5)^8 s^(−1), and the outer boundary energy spectrum, which is an exponential with an e-folding energy of 0.1 MeV. The diffusion coefficient is consistent with theoretical estimates based on the assumption that diffusion is driven by atmospheric neutral winds.