On Jupiter's moon Io, volcanic hot gases form an atmosphere that is then ionized and distributed around its orbit, forming a torus. Although it is known that the plasma leaks away, the leakage locations were unknown. Mendillo et al. report that sodium is ejected from the wake of the Io-torus interaction, together with a spherically symmetrical outflow region. The spatial extent of the ionospheric wake is more than twice that observed by the Galileo spacecraft, implying considerable variability.
- Michael Mendillo
- Sophie Laurent
- W. Clem Karl
