Unpublished conference/Abstract (Scientific congresses and symposiums)
Connecting planets to their moons: The auroral satellite footprints
Bonfond, Bertrand
2015Magnetospheres of Outer Planets meeting 2015
 

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Keywords :
Jupiter; aurora; Io; satellite footprints; Europa; Ganymede; Enceladus; Lisri
Abstract :
[en] Among the many features of the Giant planets’ aurorae are very special spots which move in a very distinct manner compared with the remaining of the aurora. Indeed, these spots are magnetically connected with planetary satellites and rotate around the poles at the same pace as their parent moon. These features, called the satellite footprints, are the signature of the electromagnetic interaction between the moons and the rapidly rotating magnetosphere plasma. On Jupiter, Io, Europa and Ganymede (and possibly Callisto) have their respective footprints while only the Enceladus footprint has been detected on Saturn so far. Several models of the interaction between Io and the jovian magnetosphere, from the unipolar inductor to the ideal Alfvén wings model, have been proposed well before the first observations of the footprints in 1993. However, the continuously improving technologies and observing methods gave rise to more accurate observations that challenged several aspects of these models and lead to further refinements. For example, when analyzed in detail, high resolution images of the aurorae show that the footprints of Io and Ganymede are not made of one, but several spots, and that the footprint of Io, Europa and Ganymede can be followed by an extended tail. The respective motion of these spots as a function of the orientation of the planetary magnetic field suggests that the Alfvén waves launched from these satellites accelerate the electrons in both directions along the field lines, hence doubling the number of visible spots, Moreover, studies of the satellite footprints are not only useful to unveil some key aspects of the moon-magnetosphere interactions, but they also contribute to the understanding of the whole magnetospheric system. For instance, their locations have been used as landmarks to constrain magnetic field models or to more accurately relate some auroral structures with their root region in the magnetosphere.
Research center :
LiSRI - Liège Space Research Institute - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Bonfond, Bertrand  ;  Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)
Language :
English
Title :
Connecting planets to their moons: The auroral satellite footprints
Publication date :
03 June 2015
Event name :
Magnetospheres of Outer Planets meeting 2015
Event organizer :
Geogia Institute of Technology
Event place :
Atlanta, United States - Georgia
Event date :
du 1 juin 2015 au 5 juin 2015
By request :
Yes
Audience :
International
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
Commentary :
Invited tutorial talk
Available on ORBi :
since 04 June 2015

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