High Pressure Experiments for Astrophysics

Abstract

In the past decade, measurements of the properties of H 2 and He systems at very high pressures have made great progress, now reaching density at the limit of the plasma phase transition of hydrogen. The potentialities and limits of static and dynamic methods will be reviewed. Then, a survey of the major experimental results is presented. It is the intention of this article to show how these measurements can bring information to model low-mass astrophysical objects. Three levels of usefulness are distinguished on selected examples: data for codes of planetary interiors, constraints for theoretical descriptions of dense matter, observations of unsuspected properties at very high density. AbstractDe grands progres ont ete faits ces dix dernieres annees dans la mesure des proprietes des systemes d^ et d*He sous tres fortes pressions. Des densites a la limite de la transition de phase plasma de lliydrogene peuvent maintenant etre obtenues en laboratoire. Les possibilites et limites des methodes dynamiques et statiques seront tout d'abord discutees. Ensuite, les principaux resultats experimentaux seront presentes. Le but de cet article est de montrer comment ces etudes peuvent etre utiles a la modelisation des interieurs planetaires. Trois niveaux d'application seront degages: donnees pour les codes de structures internes; contraintes pour valider les descriptions theoriques; mise en evidence a tres haute densite de comportements inhabituels .