title: Properties of warm dense polystyrene plasmas along the principal Hugoniot.
abstract: Polystyrene (CH) is often chosen as the ablator material for inertial confinement fusion (ICF) targets. Its static, dynamical, and optical properties in warm, dense conditions (due to shock compression) are important for ICF designs. Using the first-principles quantum molecular dynamics (QMD) method, we have investigated the equation of state (EOS) and optical reflectivity of shock-compressed CH up to an unprecedentedly high pressure of 62 Mbar along the principal Hugoniot. The QMD results are compared with existing experimental measurements as well as the SESAME EOS model. Although the Hugoniot pressure and/or temperature from QMD calculations agrees with experiments and the SESAME EOS model at low pressures below 10 Mbar, we have identified for the first time a stiffer behavior of shocked CH at higher pressures (>10 Mbar). Such a stiffer behavior of warm, dense CH can affect the ablation pressure (shock strength), shock coalescence dynamics, and nonuniformity growth in ICF implosions. In addition, we corrected the mistake made in literature for calculating the reflectivity of shocked CH and obtained good agreements with experimental measurements, which should lend credence to future opacity calculations in a first-principles fashion.
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA.
authors.forename: S X
authors.initials: SX
authors.lastname: Hu
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Boehly
authors.affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Collins
mesh_terms: D003198:Computer Simulation; D055119:Elastic Modulus; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D058626:Plasma Gases / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D011312:Pressure; D012212:Rheology / Q000379:methods*; D013696:Temperature
chemical_list: D058626:Plasma Gases; D011137:Polystyrenes