Thermodynamic properties and electrical conductivity of hydrogen under multiple shock compression to 150 GPa

Ternovoǐ, V. Ya.; Filimonov, A. S.; Fortov, V. E.; Kvitov, S. V.; Nikolaev, D. N.; Pyalling, A. A.

doi:10.1016/s0921-4526(98)01303-9

Cited by 66 publications

(30 citation statements)

References 14 publications

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“…Earlier we found a similar effect for pure hydrogen at T = 10 4 K in the region of pressure ionization and showed that in the transition region a number of large clusters (droplets) were formed [26,27]. In this region of pressure ionization the PPT was predicted by many authors [6,7,[9][10][11][28][29][30] and moreover a sharp electrical conductivity rise was measured in [31]. The instabilities in our calculations indicate the existence of PPT in dense hydrogen.…”

Section: Simulation Resultssupporting

confidence: 80%

“…From shock-wave experiments one can estimate the range of temperature and density where a sharp electrical conductivity rise takes place. In quasi-isentropic compression the transition from a low-conductivity state to a high-conductivity one for hydrogen occurs at T ∼ 3 − 15 kK and ρ ∼ 0.4 − 0.7 g/cm 3 [31,33] whereas for helium at T ∼ 15 − 40 kK and ρ ∼ 0.7 − 1.25 g/cm 3 [34]. However it is not enough to determine the region of existence of the PPT.…”

Section: Simulation Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Thermodynamics of Hydrogen and Hydrogen‐Helium Plasmas: Path Integral Monte Carlo Calculations and Chemical Picture

Филинов

Levashov

Bönitz

et al. 2005

Contrib. Plasma Phys.

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In this paper we study thermodynamic properties of hydrogen and hydrogen-helium mixtures with the help of the direct path integral Monte Carlo simulations. The results are compared with available theoretical and experimental methods based, in particular, on chemical picture. We investigate the effects of temperature ionization in low-density hydrogen plasma. We also present a number of calculated isotherms for hydrogenhelium mixture with the mass concentration of helium Y = 0.234 in the range from 10 4 K to 2 · 10 5 K. In the density region where a sharp conductivity rise have been observed experimentally the simulations give indications for one or two plasma phase transitions, in accordance with earlier theoretical predictions.

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Section: Simulation Resultssupporting

confidence: 80%

Section: Simulation Resultsmentioning

confidence: 99%

Thermodynamics of Hydrogen and Hydrogen‐Helium Plasmas: Path Integral Monte Carlo Calculations and Chemical Picture

Филинов

Levashov

Bönitz

et al. 2005

Contrib. Plasma Phys.

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show abstract

“…Such behavior is typical for Monte Carlo simulations of metastable systems. In this region of pressure ionization the PPT was predicted by many authors [6,7,[9][10][11][27][28][29] and moreover a sharp electrical conductivity rise was measured in [30]. These instabilities in our calculations indicate the existence of PPT in dense hydrogen.…”

Section: Simulation Resultssupporting

confidence: 67%

Phase transitions in dense hydrogen - helium plasmas

Филинов¹

2004

AIP Conference Proceedings

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In this paper we study thermodynamic properties of hydrogen-helium mixtures with the help of direct Path-Integral Monte Carlo simulations. Presented are preliminary results of pressure and energy isotherms in the range from 10 4 K to 2 · 10 5 K in comparison with available theoretical and experimental results. In the density region, where experiments have observed a sharp conductivity rise the simulations yield indications for one or two plasma phase transitions, in accordance with earlier predictions.

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“…A transition temperature of ∼ 2,600 K was estimated using a model equation of state (EOS). Measuring the compressibility of reverberating shocked deuterium, Fortov et al(16) measured a 20% increase of the density of the liquid in the regime where previous experiments on hydrogen (15,(17)(18)(19) have detected a sharp increase of conductivity of roughly 5 orders of magnitude, supporting the idea that dissociation and metallization occur simultaneously. However, the data were too sparse to establish the presence of a phase transition.…”

mentioning

confidence: 87%

Liquid–liquid phase transition in hydrogen by coupled electron–ion Monte Carlo simulations

Pierleoni

Morales

Rillo

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

109

141

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The phase diagram of high-pressure hydrogen is of great interest for fundamental research, planetary physics, and energy applications. A first-order phase transition in the fluid phase between a molecular insulating fluid and a monoatomic metallic fluid has been predicted. The existence and precise location of the transition line is relevant for planetary models. Recent experiments reported contrasting results about the location of the transition. Theoretical results based on density functional theory are also very scattered. We report highly accurate coupled electron-ion Monte Carlo calculations of this transition, finding results that lie between the two experimental predictions, close to that measured in diamond anvil cell experiments but at 25-30 GPa higher pressure. The transition along an isotherm is signaled by a discontinuity in the specific volume, a sudden dissociation of the molecules, a jump in electrical conductivity, and loss of electron localization.high pressure | phase transitions | quantum Monte Carlo | hydrogen metallization | molecular dissociation H ydrogen is the simplest element of the periodic table and a paradigmatic element in developing general physical theories of condensed matter. Despite the simple electronic structure, its phase diagram is unexpectedly rich, ranging from the normal three-phase equilibria (solid-liquid-gas) of the lowpressure molecular system to the fully dissociated and ionized plasma states at extreme conditions of temperature and pressure. Accurate knowledge of its phase diagram is highly relevant as testified by the continuing intense research activity over the last half century (1-5). Its relevance in nature arises because it is the most abundant element in the universe and, together with the next simplest element helium, constitutes 70-90% of the atmosphere of the giant planets, Jupiter and Saturn, and of the many, recently discovered, exoplanets. Also, it is the putative element for nuclear fusion for energy applications.The longest outstanding issue concerns the metal-insulator transition and its interplay with molecular dissociation. Molecular dissociation can occur either upon increasing temperature in the low-pressure fluid or upon increasing pressure in the low-temperature crystalline phase, or even as a combined action of temperature and pressure in the denser molecular fluid (5). The first prediction of metallization at zero temperature suggested that the molecular crystal would become atomic and transform to a simple metal above 25 GPa (1). Later experiments with higher pressures up to at least 360 GPa have found no convincing evidence of the metallic state at least below room temperature. However, they have revealed a rich phase diagram with a sequence of phase transformations in the molecular solid and the possibility of a semimetallic state (3, 6-13).The metallic state has been unequivocally observed in the dense fluid in the range of 100-200 GPa and estimated temperatures of 2,000-3,000 K by dynamical compression experiments (5, 14-16). Using the ...

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Thermodynamic properties and electrical conductivity of hydrogen under multiple shock compression to 150 GPa

Cited by 66 publications

References 14 publications

Thermodynamics of Hydrogen and Hydrogen‐Helium Plasmas: Path Integral Monte Carlo Calculations and Chemical Picture

Thermodynamics of Hydrogen and Hydrogen‐Helium Plasmas: Path Integral Monte Carlo Calculations and Chemical Picture

Phase transitions in dense hydrogen - helium plasmas

Liquid–liquid phase transition in hydrogen by coupled electron–ion Monte Carlo simulations

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