A cometary ionosphere model for Io

摘要: The ionosphere of Jupiter's satellite Io, discovered by the Pioneer 10 radio-occultation experiment, cannot easily be understood in terms a model gravitationally bound, Earth-like ionosphere. Io's gravitational field is so weak that bound would probably blown away ram force Jovian ‘magnetospheric wind’ — i.e., plasma corotating magnetosphere. We propose here which material for atmosphere and drawn from Jupiter through Birkeland current system driven potential induced across Io corotation electric field. argue ionization near caused comet-like interaction between atmosphere. initial employs critical velocity phenomenon proposed many years ago Alfven. Further produced impact trapped energetic electrons, thus created swept out ahead its orbit. Thus, we suggest what has been reported as day-night ionospheric asymmetry fact an upstream-downstream magnetospheric wind.