The first meter of the surface of the Galilean satellites is built of a regolith, a very porous environment, mixture of water ice and rocks, permanently impacted by the energetic particles from the Jovian magnetosphere and by the solar radiation. Their atmosphere, so thin that they are called exosphere, is one of the products of the processes of aging of their surface. The observation of these exospheres, today from the Earth thanks to Hubble Space Telescope or to James Webb Space Telescope or in situ thanks to JUNO and in a near future thanks to JUICVE, therefore provides key information to reconstruct up to the smallest scales the mechanisms which, permanently erode and change these surfaces.

The great advantage of the three Galilean satellites, Europa, Ganymede and Callisto is that they offer to us the opportunity to probe three environments and planetary objects of close composition but different enough to produce very different exospheres, in terms of composition, spatial distribution and relations to their surface. Why are there such differences and what control the origins remain a challenge to solve to well understand the observations that can be performed of their surface.

The goal of this PhD will be to combine GEOPS’s model about near surface processes and LATMOS’ efforts of modelling of these three objects by integrating in Exospheric Global Model (EGM), a new extension, developed in the case of Mercury, and which describes allows the description of the fate of exospheric particles in the first meter of the surface. This model, coupled with Molecular Dynamics simulations towhich describe the atomic scales, will allow the modelingdescription of the diffusion, absorption and desorption of the observed exospheric species. Coupled to a thermal model of the surface from GEOPS, the objective of this PhD is to model the diurnal and orbital evolution of these three exospheres and the available observations. The outputs of EGM will be also used in a magnetospheric model, LATMOS Hybrid Simulation (LatHyS), in order to simulate the few in situ measurements of the plasma environment of these objects. 

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For more Information about the topics and the co-financial partner (found by the lab!); contact Directeur de thèse - francois.leblanc@latmos.ipsl.fr

Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 13th, 2026 Midnight Paris time!