title: Planetary science. Shock compression of stishovite and melting of silica at planetary interior conditions.
abstract: Deep inside planets, extreme density, pressure, and temperature strongly modify the properties of the constituent materials. In particular, how much heat solids can sustain before melting under pressure is key to determining a planet's internal structure and evolution. We report laser-driven shock experiments on fused silica, α-quartz, and stishovite yielding equation-of-state and electronic conductivity data at unprecedented conditions and showing that the melting temperature of SiO2 rises to 8300 K at a pressure of 500 gigapascals, comparable to the core-mantle boundary conditions for a 5-Earth mass super-Earth. We show that mantle silicates and core metal have comparable melting temperatures above 500 to 700 gigapascals, which could favor long-lived magma oceans for large terrestrial planets with implications for planetary magnetic-field generation in silicate magma layers deep inside such planets.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. University of California Berkeley, Berkeley, CA 94720, USA. millot1@llnl.gov.
authors.forename: M
authors.initials: M
authors.lastname: Millot
authors.affiliation: Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Dubrovinskaia
authors.affiliation: Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Černok
authors.affiliation: Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Blaha
authors.affiliation: Bayerisches Geoinstitut, University of Bayreuth, 95440 Bayreuth, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Dubrovinsky
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Braun
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Celliers
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: Collins
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Eggert
authors.affiliation: University of California Berkeley, Berkeley, CA 94720, USA.
authors.forename: R
authors.initials: R
authors.lastname: Jeanloz