Io's auroral footprints: A study of the interaction between Io and Jupiter

Abstract:

The electromagnetic interaction between Jupiter and its innermost Galilean moon Io is a prime example for moon-planet and star-planet interaction. Very striking features are the Io footprints (IFP) in Jupiter’s upper atmosphere. With the Juno spacecraft orbiting Jupiter, new insights about the complex structure of the IFP and the associated tail have been achieved which can not be fully explained by existing models. A deeper understanding is necessary to explain in particular the complex tail morphology patterns observed by Mura et al. 2018.

We investigate different aspects of the Io-Jupiter interaction that could cause the observed structures. For that purpose we use the Poynting flux of the Alfvén wings as a proxy for the shape, intensity and distribution of footprints. Idealized analytical calculations as well as simulations with the single fluid MHD-Code Pluto are carried out to study the Alfvén wing generated by Io in detail. In our study, we use a model similar to Jacobsen et al. 2007 with a constant magnetic field and spatially varying density. Then we increase the complexity of this model by including a more realistic wave generator, i.e. Io, and a more complex model of the Jovian inner magnetosphere. Here, we focus on the reflection pattern of the Alfvén wings at the torus boundary and the Jovian ionosphere and how it affects the morphology and the properties of the Alfvén wings.