General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DRF-27-0226
Direction
DRF
Thesis topic details
Category
Corpuscular physics and outer space
Thesis topics
Protoplanetary disk formation at the exascale era
Contract
Thèse
Job description
Recent observations of protoplanetary disks indicate that planets begin to form during the first million years of their evolution. However, state-of-the-art simulations of disk formation struggle to follow their evolution beyond 100,000 years. Two obstacles are at the root of this limitation. First, the numerical schemes that include the magnetic field are strongly constrained by non-ideal MHD that imposes a quadratic decrease of the timestep with the resolution; this becomes prohibitive once disks are spatially resolved. Second, over such long periods of time, it becomes necessary to model scales that go beyond the prestellar core that constitutes the initial mass reservoir of the disk. We must therefore model the entire molecular clouds, that is to say from the parsec scales down to the astronomical unit, while considering secular times. This is out of reach for commonly used numerical codes. In this thesis, we propose to remove these two technical barriers. We will develop a non-ideal MHD scheme based on the 'heavy ion' method, which is appropriate because dust grains are the main charge carriers during the collapse. Since this approach does not require a diffusion term, it will accelerate the treatment of the magnetic field. Furthermore, it will be implemented in DYABLO, a new code developed at CEA that provides GPU acceleration, unlocking the multi-scale aspect of the project. Building on these developments, we will study the influence of the environment on disks and the formation of planetesimals in order to determine the timing of planet formation.
University / doctoral school
Science de la Terre et de l’Environnement et Physique de l’Univers Paris (STEPUP)
Paris Cité
Thesis topic location
Site
Saclay
Requester
Position start date
01/10/2027
Person to be contacted by the applicant
Lebreuilly Ugo
ugo.lebreuilly@cea.fr
CEA
DRF/IRFU/DAp/LMPA
Orme des merisiers, Bât 709
91190, Gif sur Yvette
0169081863
Tutor / Responsible thesis director
GONZALEZ Matthias
matthias.gonzalez@cea.fr
Université Paris Cité
DRF/IRFU/DAp/LMPA
Bat 709 - Pce 230C
Orme des Meurisiers
CEA Saclay
91191 Gif sur Yvette
33 1 69 08 17 79
En savoir plus
https://ulebreui.github.io/
https://irfu.cea.fr/dap/modelisation-des-plasmas-astrophysiques/
https://irfu.cea.fr/Pisp/matthias.gonzalez/