The equation of state of iron to 450 GPa: Another high pressure solid phase?

The high-pressure, high-temperature behavior of iron was investigated to 140 GPa and 3500 K with in situ synchrotron X-ray diffraction. Iron samples were compressed in diamond-anvil cells and heated up with the double-sided laser-heating system installed at the high-pressure ID27 of the European Synchrotron Radiation Facility (ESRF). Three different structures, namely α-bcc, γ-fcc or ε-hcp Fe were identified as a function of pressure and temperature in the domain we explored. At pressures above 90 GPa, it is clearly shown that ε-iron is the single stable solid phase up to 160 GPa at high temperatures. The analysis of the P-V-T relationship allows us to propose a reliable experimental thermal equation of state (EoS) for iron. We also show that the addition of low pressure points to our EoS refinement yields more robust constrain on the determination of the reference volume V0 of the ε-hcp structure, which has important implications on the final parametrization of the equation of state. The extrapolation of the proposed EoS to core pressure conditions indicates that a pure iron core would have an excess of density of 3% compared to the PREM density profile.

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Testing a simple method for computing directly the bulk modulus by NPT simulation: The case of polydisperse hard sphere solids

International Journal of Modern Physics C ◽

10.1142/s0129183115500576 ◽

2015 ◽

Vol 26 (05) ◽

pp. 1550057

Author(s):

Da Li ◽

Hong Xu

Keyword(s):

High Pressure ◽

Equation Of State ◽

Bulk Modulus ◽

Hard Sphere ◽

Solid Phase ◽

Component Mixture ◽

Simple Method ◽

Illustrative Purpose ◽

The One ◽

Pressure Regime

The bulk modulus of hard sphere solids has been computed directly by constant pressure Monte-Carlo simulations, using the histogram of the volume fluctuations. In considering first the one-component system, we show that the method is accurate in a large range of pressures, including high-pressure regime. The method is then applied to a polydisperse solid with relatively low polydispersity index. For illustrative purpose, we took a three-component mixture with symmetric size-distribution, and we studied the solid phase (fcc crystal) of this system. Our results show that the equation of state is very sensitive to the polydispersity. Furthermore, in the high-pressure region, where no (accurate) analytical fit for the equation of state exists, our simulations are able to predict the bulk modulus of such systems.

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Equation of state studies at SILP by laser-driven shock waves

Laser and Particle Beams ◽

10.1017/s0263034600009915 ◽

1996 ◽

Vol 14 (2) ◽

pp. 157-169 ◽

Cited By ~ 8

Author(s):

Yuan Gu ◽

Sizu Fu ◽

Jiang Wu ◽

Songyu Yu ◽

Yuanlong Ni ◽

...

Keyword(s):

Shock Wave ◽

High Pressure ◽

Equation Of State ◽

Shock Waves ◽

Target Surface ◽

Shock Adiabats ◽

Pressure Shock ◽

Aluminum Target ◽

Laser Illumination ◽

The Stability

The experimental progress of laser equation of state (EOS) studies at Shanghai Institute of Laser Plasma (SILP) is discussed in this paper. With a unique focal system, the uniformity of the laser illumination on the target surface is improved and a laser-driven shock wave with good spatial planarity is obtained. With an inclined aluminum target plane, the stability of shock waves are studied, and the corresponding thickness range of the target of laser-driven shock waves propagating steadily are given. The shock adiabats of Cu, Fe, SiO2 are experimentally measured. The pressure in the material is heightened remarkably with the flyer increasing pressure, and the effect of the increasing pressure is observed. Also, the high-pressure shock wave is produced and recorded in the experimentation of indirect laser-driven shock waves with the hohlraum target.

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High pressure-temperature phase diagram and equation of state of titanium

Physical Review B ◽

10.1103/physrevb.91.134108 ◽

2015 ◽

Vol 91 (13) ◽

Cited By ~ 23

Author(s):

Agnès Dewaele ◽

Vincent Stutzmann ◽

Johann Bouchet ◽

François Bottin ◽

Florent Occelli ◽

...

Keyword(s):

Phase Diagram ◽

High Pressure ◽

Equation Of State ◽

Temperature Phase ◽

Temperature Phase Diagram

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A time-dependent model for high-pressure discharges in narrow ablative capillaries

Journal of Plasma Physics ◽

10.1017/s0022377800026908 ◽

1993 ◽

Vol 50 (1) ◽

pp. 51-70 ◽

Cited By ~ 19

Author(s):

D. Zoler ◽

S. Cuperman ◽

J. Ashkenazy ◽

M. Caner ◽

Z. Kaplan

Keyword(s):

High Pressure ◽

Equation Of State ◽

Time Dependent ◽

Dimensional Model ◽

Plasma Sources ◽

One Dimensional ◽

Space And Time ◽

Dependent Model ◽

Energy Equations ◽

Time Dependent Model

A time-dependent quasi-one-dimensional model is developed for studying high- pressure discharges in ablative capillaries used, for example, as plasma sources in electrothermal launchers. The main features of the model are (i) consideration of ablation effects in each of the continuity, momentum and energy equations; (ii) use of a non-ideal equation of state; and (iii) consideration of space- and time-dependent ionization.

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