Dense plasma physics : the hydrogen-helium mixtures in planetary interiors
type: Dataset
description: The thermodynamical conditions inside the giant planets - like Jupiter, Saturn or many of the daily discovered exoplanets – are such that the interactions between particles – atoms, ions, electrons – are highly dominant in the physics of giant planets envelope s, mostly made of hydrogen and helium in a plasma phase. The heat and mechanical properties of these planets are mainly determined by these interactions. Thus, it is of crucial interest to study these dense plasmas to understand the structure and the evolution of the giant planets. The dense plasma phase of the pure compounds has been successfully characterized by ab initio simulations using density functional theory. For instance, they correctly reproduced the results obtained in high-power laser chock experiments. Nevertheless, large discrepancies remain between planetary models and observations. A proposed hypothesis is a strong influence of the H-He mixture non-ideality and possible phase separations. In this work, these ab initio numerical methods have been applied to the H-He mixtures. The thermodynamical study has shown sensitive deviations from ideal mixtures. The estimates of the transport properties (electrical and heat conductivities, optical properties...) indicate an insulator-conductor transition in the mixture, associated with hydrogen ionization. In some conditions, demixing of conducting hydrogen and neutral helium has also been observed. These computations have allowed us to determine pathways to verify our results through laser experiments. This is the first step in the establishment of a reliable equation of state of H-He mixtures, usable in giant planets modeling.
identifier: NNT: 2012ENSL0746
issued: 2026-06-02T19:56:02.833975
language: fr
modified: 2026-06-02T19:56:02.833982
contact point: Organization
  fn: CCSD
keyword: dense-plasmas
keyword: dft
keyword: giant-planets
keyword: helium
keyword: hydrogen
keyword: hydrogene
keyword: infoeu-reposemanticsdoctoralthesis
keyword: planetes-geantes
keyword: plasmas-denses
keyword: sdustusciences-of-the-universe-physicsearth-sciences
keyword: theses
landing page: https://theses.hal.science/tel-00760002

Dense plasma physics : the hydrogen-helium mixtures in planetary interiors
type: Distribution
format: HTML
issued: 2026-06-02T19:56:02.866504
modified: 2026-06-02T19:56:02.806406
access URL: https://theses.hal.science/tel-00760002

test_moissonnage_selune
type: Agent