Spectroscopic observations of Fermi-degenerate aluminum compressed and heated to four times solid density and 20 eV

Regan, S. P.; Sawada, Hiroshi; Goncharov, V. N.; Li, D.; Radha, P. B.; Epstein, R.; Delettrez, J. A.; Hu, S. X.; Smalyuk, V. A.; Yaakobi, B.; Boehly, T. R.; Sangster, T. C.; Meyerhofer, D. D.; McCrory, R. L.; Mancini, Roberto

doi:10.1016/j.hedp.2011.05.011

Cited by 5 publications

(5 citation statements)

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“…Aluminum, a simple metal, has been one of the most commonly-studied prototype materials for gaining insight into physical properties at such conditions. The wide breadth of experimental and theoretical research on aluminum includes studies of solid phase transitions [6,7], shock physics [8][9][10][11][12][13][14][15][16][17][18], x-ray diagnostics for basic plasma physics [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34], and optical [35][36][37][38][39] and transport [40][41][42][43][44][45][46][47] properties.…”

Section: Introductionmentioning

confidence: 99%

Path integral Monte Carlo simulations of warm dense aluminum

2018

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We perform first-principles path integral Monte Carlo (PIMC) and density functional theory molecular dynamics (DFT-MD) calculations to explore warm dense matter states of aluminum. Our equation of state (EOS) simulations cover a wide density-temperature range of 0.1-32.4gcm^{-3} and 10^{4}-10^{8} K. Since PIMC and DFT-MD accurately treat effects of the atomic shell structure, we find two compression maxima along the principal Hugoniot curve attributed to K-shell and L-shell ionization. The results provide a benchmark for widely used EOS tables, such as SESAME, QEOS, and models based on Thomas-Fermi and average-atom techniques. A subsequent multishock analysis provides a quantitative assessment for how much heating occurs relative to an isentrope in multishock experiments. Finally, we compute heat capacity, pair-correlation functions, the electronic density of states, and 〈Z〉 to reveal the evolution of the plasma structure and ionization behavior.

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Section: Introductionmentioning

confidence: 99%

Path integral Monte Carlo simulations of warm dense aluminum

2018

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“…This is the first observation of plasma conditions created with a compression wave. 24 The level of shock-wave heating and timing of heat-front penetration inferred from the experiments were compared with the post-processed LILAC simulations using the time-dependent atomic physics code Spect3D. 25 The shock-wave heating and heat-front penetration predicted by LILAC using f = 0.06 or the nonlocal model agree with experimental results for times when the shock is transiting the foil.…”

Section: T Tmentioning

confidence: 90%

“…This is the first measurement of the plasma temperature and density in a direct-drive target created by multiple shock waves (i.e., a weak shock and a compression wave). 24 The best fit to each spectrum is represented by the black curve. The mass densities inferred are between 5 and 7 g/cm 3 for the 1-ns square laser pulse [ Fig.…”

Section: Draco (2-d)mentioning

confidence: 99%

“…24 shows the 1-D spatial profiles of the electron temperature and mass density predicted by LILAC in a drive foil during shock-wave heating and heat-front penetration using a flux limiter of 0.06. As the shock wave launched by laser ablation propagates through the Al layer, it compresses the layer and creates uniform plasma conditions in the target behind the shock wave [Fig.…”

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confidence: 99%

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Al 1 s - 2 p absorption spectroscopy of shock-wave heating and compression in laser-driven planar foil

et al. 2009

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Time-resolved Al 1s-2p absorption spectroscopy is used to diagnose direct-drive, shock-wave heating and compression of planar targets having nearly Fermi-degenerate plasma conditions (Te∼10–40 eV, ρ∼3–11 g/cm3) on the OMEGA Laser System [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. A planar plastic foil with a buried Al tracer layer was irradiated with peak intensities of 1014–1015 W/cm2 and probed with the pseudocontinuum M-band emission from a point-source Sm backlighter in the range of 1.4–1.7 keV. The laser ablation process launches 10–70 Mbar shock waves into the CH/Al/CH target. The Al 1s-2p absorption spectra were analyzed using the atomic physic code PRISMSPECT to infer Te and ρ in the Al layer, assuming uniform plasma conditions during shock-wave heating, and to determine when the heat front penetrated the Al layer. The drive foils were simulated with the one-dimensional hydrodynamics code LILAC using a flux-limited (f=0.06 and f=0.1) and nonlocal thermal-transport model [V. N. Goncharov et al., Phys. Plasmas 13, 012702 (2006)]. The predictions of simulated shock-wave heating and the timing of heat-front penetration are compared to the observations. The experimental results for a wide variety of laser-drive conditions and buried depths have shown that the LILAC predictions using f=0.06 and the nonlocal model accurately model the shock-wave heating and timing of the heat-front penetration while the shock is transiting the target. The observed discrepancy between the measured and simulated shock-wave heating at late times of the drive can be explained by the reduced radiative heating due to lateral heat flow in the corona.

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“…Significant advances made in inertial confinement fusion (ICF) research have been enabled by x-ray spectroscopy, thus contributing to a better interpretation of the underlying physics and target performance, and to improvements in the predictive capability of simulation codes [1,2]. Among these achievements are: the measurement of target preheat due to fast electrons by means of Kα emission spectroscopy [3][4][5]; the extraction of spatially averaged electron temperature and density in implosion cores of direct-and indirect-drive implosions by analyzing Starkbroadened K-and L-shell line emissions [6][7][8][9][10][11][12][13][14]; the use of K-shell absorption spectroscopy to infer the conditions of the relatively cold imploding shell that confines the core [15][16][17][18][19]; the simultaneous determination of time-and space-averaged conditions for both core and shell in thick-wall targets by accounting for the attenuation of core x-ray emission in the compressed shell [20]; the time-resolved characterization and energy balance analysis of implosion core in shock-ignition experiments [21]; the quantitative evaluation of mixing of ablator material into the hot-spot of ignition-scale targets from the K-shell emission of mid-Z dopant elements [22][23][24]; the extraction of spatial profiles of temperature and density from the analysis of x-ray spectra and narrow-band images [25][26][27]; the asymmetry measurement of plasma temperature and density spatial profiles from pinhole space-resolved spectra [28]; and the observation of three-dimensional and laser imprinting effects in polar-drive implosions with gated spectrally resolved x-ray imaging [29]. Furthermore, the conditions achieved in laser-driven ICF capsules are similar to those in stellar interior environments, so this progress in ICF research is also likely to benefit applications in astrophysics [30].…”

Section: Introductionmentioning

confidence: 99%

Assessment of transient effects on the x-ray spectroscopy of implosion cores at OMEGA

Florido

Mancini

2015

J. Phys. B: At. Mol. Opt. Phys.

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An assessment of transient effects on the atomic kinetics of argon tracers in inertial confinement fusion implosion cores is carried out. The focus is on typical electron temperature and density conditions achieved in high-and low-adiabat, and shock-ignition implosion experiments performed at the OMEGA laser facility (Laboratory for Laser Energetics, USA). The results show that no significant time-dependent effects are present through the deceleration and burning phases of the implosion, and thus justify the use of steady-state atomic kinetics models in the spectroscopic analysis of sets of time-resolved x-ray spectra recorded with streaked or gated spectrometers. Modeling calculations suggest an onset for time-dependent effects to become important at electron densities 10 22 cm −3 . A physical interpretation of these results is given based on the atomic kinetics timescales extracted from the eigenvalue spectrum of the collisional-radiative rate matrix. This study is also relevant for past implosion experiments performed at the GEKKO XII laser (Institute of Laser Engineering, Japan), as well as those currently being performed at the National Ignition Facility (Lawrence Livermore National Laboratory, USA).

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Spectroscopic observations of Fermi-degenerate aluminum compressed and heated to four times solid density and 20 eV

Cited by 5 publications

References 37 publications

Path integral Monte Carlo simulations of warm dense aluminum

Path integral Monte Carlo simulations of warm dense aluminum

Al 1 s - 2 p absorption spectroscopy of shock-wave heating and compression in laser-driven planar foil

Assessment of transient effects on the x-ray spectroscopy of implosion cores at OMEGA

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