Magnetospheric interaction with Triton's ionosphere



The large electron densities measured by the Voyager radio occultation experiment are attributed to the precipitation of magnetospheric electrons with energy > 10 keV. Because the ionospheric electric Pedersen conductivity of Triton is,∼ (1−2) × 104 mho and the Alfven conductance is ∼ 3.5 mho, direct connective flow of plasma into the essentially infinitely conducting ionosphere is negligible. Magnetospheric electrons are transported to Triton's ionopause by curvature drift as a result of weak magnetic field line draping in a sub-Alfvenic plasma interaction with Triton. At the ionopause energetic electrons have a high probability of elastic and inelastic scattering and precipitate into the upper atmosphere. The average power dissipation is estimated to be ∼ (2−3) × 108 W.