Magnetically launched flyer plate technique for probing electrical conductivity of compressed copper

Cochrane, Kyle; Lemke, R.W.; Riford, Z.; Carpenter, John H.

doi:10.1063/1.4943417

Cited by 24 publications

(5 citation statements)

References 53 publications

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“…Both simulations used the Kerley03 28 EOS for hydrogen (a modern revision of the lation with the same magnitude first shock followed by ramp compression to the same peak P (method 2). In these simulations EOS models 3325, 29,30 3700, 31,32 and 7411 33 were used to model copper, aluminum, and sapphire, respectively. As can be seen in the figure, T in the peak state for these two simulations differs by over 500 K. This is completely explained by the difference in entropy of the final states for the two different methods used by NWM.…”

Section: Reanalysis Of Multiple-shock Conductivity Experimentsmentioning

confidence: 99%

Evaluation of exchange-correlation functionals with multiple-shock conductivity measurements in hydrogen and deuterium at the molecular-to-atomic transition

et al. 2018

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The temperature (T) and density (ρ) conditions at which hydrogen undergoes a molecular-toatomic (MA) transition is crucial to our understanding of the gas-giant planets such as Jupiter and Saturn. First-principles (FP) calculations suggest that this transition is coincident with metallization and acts as a catalyst for hydrogen-helium demixing, which has significant consequences for models of planetary interiors. Prediction of this transition boundary has proven to be difficult using FP methods. In particular, detailed comparisons of finite temperature density functional theory (FT-DFT) calculations of the MA transition in both the high-T , low-ρ regime, where the transition is largely T-driven, and the low-T , high-ρ regime, where the transition is largely ρ-driven, suggest that the transition is very sensitive to the exchange-correlation (xc) functional used in the calculation. Here we present a detailed comparison of previous multiple-shock electrical conductivity measurements with FT-DFT calculations employing various xc functionals to probe a regime where both T and ρ play an important role in the transition. The measurement results are found to be inconsistent with the semi-local xc functional PBE, and are in much better agreement with the nonlocal xc functionals vdW-DF1 and vdW-DF2. Furthermore, we show that the inconsistency with PBE likely stems from pressure errors associated with the PBE xc functional, resulting in calculated pressures that are too low at these T and ρ conditions. Together with previous comparisons at high-T , low-ρ and low-T , high-ρ these results provide a consistent picture for the MA transition over a wide T and ρ range. This picture may also provide insight into differences in experimental observations of the metallization of liquid hydrogen and deuterium in the low-T regime.

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Section: Reanalysis Of Multiple-shock Conductivity Experimentsmentioning

confidence: 99%

Evaluation of exchange-correlation functionals with multiple-shock conductivity measurements in hydrogen and deuterium at the molecular-to-atomic transition

et al. 2018

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“…The cold pressure curves are plotted in figures 3 and 4 for Al and Cu, respectively, along with data assembled from the literature [37][38][39][40][41][42][43][44]. Each curve is the 'repulsive' pressure, calculated from the TFDW model (equation ( 24)), minus the 'attractive' pressure (equation ( 35)).…”

Section: Simulation Resultsmentioning

confidence: 99%

Finite-temperature Thomas–Fermi–Dirac-Weizsäcker model in the warm dense matter regime

Petrov¹

2023

Plasma Phys. Control. Fusion

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The Thomas-Fermi-Dirac-Weizsäcker model for finite temperature is presented. Starting with the free energy density, consistent expressions for the Helmholtz free energy, total energy, pressure and virial theorem are derived. The exchange and correlation terms are cast in form that is suitable for derivation of their contributions to energy and pressure. The Euler-Lagrange equation is written in Schrödinger-like form and solved in spherical symmetry in a Wigner-Seitz cell. The challenges associated with its numerical solution have been discussed and a viable approach to obtain a non-negative solution is proposed. The model is benchmarked for two materials, Al and Cu, by comparing the pressure at solid density in the temperature range 0.1<T_e<10 eV, as well as the cold pressure curves.

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“…To date, the most accurate data for electrical conductivity for Cu have been produced at Sandia National Laboratory using two approaches: DFT and Lee-More-Desjarlais model [40]. The data from the latter were fine-tuned using experimental data on the Thor pulsed-power driver [41,42]. These data are also presented in figure 5 for comparison.…”

Section: Numerical Modeling Of Cu Using the Average Atom Model Collis...mentioning

confidence: 99%

Collisional and transport parameters of Cu in the warm dense matter regime calculated using the average atom model

Petrov¹,

Davidson²

2021

Plasma Phys. Control. Fusion

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Collisional and transport parameters for Cu are computed using the average atom model. Transition metals such as copper are difficult to model within the framework of the average atom model due to the presence of a narrow band of 3d electrons that mix and hybridize with the broad 4s band of nearly-free electrons. With electron temperature increasing, the 3d electrons play a key role in the thermodynamics and transport properties of Cu (Lin et al 2008 Phys. Rev. B 77 075133), as well as the stability of the lattice (Loboda et al 2011 High Energy Density Phys. 7 361). In this work, the average atom model was used to track the average energy of the 3d band and its evolution with electron temperature. At room temperature, its center is at ∼6 electron volts (eV), a few electron-volts below the Fermi energy, and with electron temperature increasing it sinks relative to it. At electron temperature of about 8 eV the 3d electrons leave the conduction band and become bound. A long-standing problem related to the average ion charge observed by conduction band electrons is addressed and successfully resolved. A work-around has been found that predicts the correct average ion charge, Z ˉ , by formally introducing a third group of electrons: quasi-bound electrons. Benchmarking with published data is made that shows good agreement.

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Magnetically launched flyer plate technique for probing electrical conductivity of compressed copper

Cited by 24 publications

References 53 publications

Evaluation of exchange-correlation functionals with multiple-shock conductivity measurements in hydrogen and deuterium at the molecular-to-atomic transition

Evaluation of exchange-correlation functionals with multiple-shock conductivity measurements in hydrogen and deuterium at the molecular-to-atomic transition

Finite-temperature Thomas–Fermi–Dirac-Weizsäcker model in the warm dense matter regime

Collisional and transport parameters of Cu in the warm dense matter regime calculated using the average atom model

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