Speed of sound in solid molecular hydrogen-deuterium: Quantum Molecular Dynamics Approximation

9th International Conference on Inertial Fusion Sciences and Applications

Guerrero, Carlo Luis^1 ; Perlado, Jose Manuel^1

Nuclear Fusion Institute, ETSII, Polytechnic University of Madrid, Madrid

28006, Spain^1

关键词: Ab initio method;    Compression process;    Deuterium-tritium;    Dynamic compression;    Quantum molecular dynamics;    Rayleigh-Taylor instabilities;    Solid molecular hydrogen;    Thermo-mechanical;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/717/1/012018/pdf
DOI  :  10.1088/1742-6596/717/1/012018

来源: IOP

【 摘 要 】

Uniformity of the solid layer is one of the critical points for an efficient ignition of the Deuterium-Tritium (DT) target. During the compression process this layer, perturbations grow as the Rayleigh-Taylor instability. Knowing the mechanical properties of this layer and its thermo-mechanical limits is necessary if we want to control or to minimize these instabilities. In this work we have used a simplified approach, replacing the DT ice system with a mixture of hydrogen-deuterium (HD) because beta decay of tritium complicates the analysis in the former case. Through simulation with ab initio methods we have calculated the elastic constants, the bulk modulus and sound velocity for hydrogen isotopes in solid molecular state. In this work we present the results for hydrogen-deuterium mixtures 50%-50%, at 15 K and with a compression which covers the range of 1 to 15 GPa. This system is interesting for study the early stages of the dynamic compression and provides conditions that are close to the manufacture of DT target in inertial confinement fusion. Discontinuities in the curve that have been observed on pure hydrogen, which are associated with phase transitions and the phase hysteresis.