Continuous Sound Velocity Measurements along the Shock Hugoniot Curve of Quartz
| Autor: | Chengwei Sun, Feng Wang, Hongping Zhang, Gongmu Zhang, Raymond Jeanloz, Jianheng Zhao, Mu Li, Shuai Zhang |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Bulk modulus Shock (fluid dynamics) Equation of state (cosmology) General Physics and Astronomy 01 natural sciences Ideal gas Thermal expansion Dissociation (psychology) 010305 fluids & plasmas 0103 physical sciences medicine Density functional theory medicine.symptom Atomic physics 010306 general physics Stishovite |
| Zdroj: | Physical review letters. 120(21) |
| ISSN: | 1079-7114 |
| Popis: | We report continuous measurements of the sound velocity along the principal Hugoniot curve of $\ensuremath{\alpha}$ quartz between 0.25 and 1.45 TPa, as determined from lateral release waves intersecting the shock front as a function of time in decaying-shock experiments. The measured sound velocities are lower than predicted by prior models, based on the properties of stishovite at densities below $\ensuremath{\sim}7\text{ }\text{ }\mathrm{g}/{\mathrm{cm}}^{3}$, but agree with density functional theory molecular dynamics calculations and an empirical wide-regime equation of state presented here. The Gr\"uneisen parameter calculated from the sound velocity decreases from $\ensuremath{\gamma}\ensuremath{\sim}1.3$ at 0.25 TPa to 0.66 at 1.45 TPa. In combination with evidence for increased (configurational) specific heat and decreased bulk modulus, the values of $\ensuremath{\gamma}$ suggest a high thermal expansion coefficient at $\ensuremath{\sim}0.25--0.65\text{ }\text{ }\mathrm{TPa}$, where ${\mathrm{SiO}}_{2}$ is thought to be a bonded liquid. From our measurements, dissociation of the molecular bonds persists to $\ensuremath{\sim}0.65--1.0\text{ }\text{ }\mathrm{TPa}$, consistent with estimates by other methods. At higher densities, the sound velocity is close to predictions from previous models, and the Gr\"uneisen parameter approaches the ideal gas value. |
| Databáze: | OpenAIRE |
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