title: Ramp compression of diamond to five terapascals.
abstract: The recent discovery of more than a thousand planets outside our Solar System, together with the significant push to achieve inertially confined fusion in the laboratory, has prompted a renewed interest in how dense matter behaves at millions to billions of atmospheres of pressure. The theoretical description of such electron-degenerate matter has matured since the early quantum statistical model of Thomas and Fermi, and now suggests that new complexities can emerge at pressures where core electrons (not only valence electrons) influence the structure and bonding of matter. Recent developments in shock-free dynamic (ramp) compression now allow laboratory access to this dense matter regime. Here we describe ramp-compression measurements for diamond, achieving 3.7-fold compression at a peak pressure of 5 terapascals (equivalent to 50 million atmospheres). These equation-of-state data can now be compared to first-principles density functional calculations and theories long used to describe matter present in the interiors of giant planets, in stars, and in inertial-confinement fusion experiments. Our data also provide new constraints on mass-radius relationships for carbon-rich planets.
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Smith
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Eggert
authors.affiliation: Department of Earth and Planetary Science, Department of Astronomy and Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, USA.
authors.forename: R
authors.initials: R
authors.lastname: Jeanloz
authors.affiliation: Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: T S
authors.initials: TS
authors.lastname: Duffy
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Braun
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Patterson
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Rudd
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: J
authors.initials: J
authors.lastname: Biener
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Lazicki
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Hamza
authors.affiliation: Department of Earth and Planetary Science, Department of Astronomy and Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, USA.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: T
authors.initials: T
authors.lastname: Braun
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: L X
authors.initials: LX
authors.lastname: Benedict
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Celliers
authors.affiliation: Lawrence Livermore National Laboratory, PO Box 808, Livermore, California 94550, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: Collins