X-ray scattering measurements on imploding CH spheres at the National Ignition Facility

Kraus, D.; Chapman, D. A.; Kritcher, Andrea; Baggott, R. A.; Bachmann, B.; Collins, G. W.; Glenzer, S. H.; Hawreliak, J.; Kalantar, D. H.; Landen, O. L.; Ma, T.; Pape, S. Le; Nilsen, Joseph; Swift, Damian; Neumayer, P.; Falcone, R. W.; Gericke, Dirk O.; Döppner, T.

doi:10.1103/physreve.94.011202

Cited by 75 publications

(46 citation statements)

References 37 publications

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“…The highest pressure achieved among these experiments is 40 Mbar [14,15], which is yet not high enough to probe the effects of Kshell ionization on the shock Hugoniot curve. Since the first X-ray scattering results on CH at above 0.1 Gbar (1 Gbar=100 TPa) [33], ongoing, spherically-converging shock experiments using the Gbar platform at the National Ignition Facility (NIF) [34][35][36][37][38] and the OMEGA laser [39] will extend measurements of the shock Hugoniot curve of polystyrene to pressures above 0.35 Gbar and into the K-shell ionization regime [40]. …”

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confidence: 99%

First-principles equation of state and shock compression predictions of warm dense hydrocarbons

et al. 2017

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We use path integral Monte Carlo and density functional molecular dynamics to construct a coherent set of equation of state for a series of hydrocarbon materials with various C:H ratios (2:1, 1:1, 2:3, 1:2, and 1:4) over the range of 0.07 − 22.4 g cm −3 and 6.7 × 10 3 − 1.29 × 10 8 K. The shock Hugoniot curve derived for each material displays a single compression maximum corresponding to K-shell ionization. For C:H=1:1, the compression maximum occurs at 4.7-fold of the initial density and we show radiation effects significantly increase the shock compression ratio above 2 Gbar, surpassing relativistic effects. The single-peaked structure of the Hugoniot curves contrasts with previous work on higher-Z plasmas, which exhibit a two-peak structure corresponding to both K-and L-shell ionization. Analysis of the electronic density of states reveals that the change in Hugoniot structure is due to merging of the L-shell eigenstates in carbon, while they remain distinct for higher-Z elements. Finally, we show that the isobaric-isothermal linear mixing rule for carbon and hydrogen EOSs is a reasonable approximation with errors better than 1% for stellar-core conditions.Introduction. Hydrocarbon ablator materials are of primary importance for laser-driven shock experiments, such as those central to the study of inertial confinement fusion (ICF) [1][2][3] and the measurement of high energy density states relevant to giant planets [4] and stellar objects [5]. Accurate knowledge of the equation of state (EOS) of the hydrocarbon ablator is essential for optimizing experimental designs to achieve desired density and temperature states in a target. Consequently, a number of planar-driven shock wave experiments have been performed on hydrocarbon materials, including polystyrene (CH) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], glow-discharge polymer (GDP) [24][25][26][27][28], and foams [29][30][31][32], to measure the EOS. The highest pressure achieved among these experiments is 40 Mbar [14,15], which is yet not high enough to probe the effects of Kshell ionization on the shock Hugoniot curve. Since the first X-ray scattering results on CH at above 0.1 Gbar (1 Gbar=100 TPa) [33], ongoing, spherically-converging shock experiments using the Gbar platform at the National Ignition Facility (NIF) [34][35][36][37][38] and the OMEGA laser [39] will extend measurements of the shock Hugoniot curve of polystyrene to pressures above 0.35 Gbar and into the K-shell ionization regime [40].

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confidence: 99%

First-principles equation of state and shock compression predictions of warm dense hydrocarbons

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“…In particular, the ionization potential

I_{normali}^{((), 0)}

of the isolated ion is reduced, and the difference

Δ I_{normali} = I_{normali}^{((), 0)} - I_{normali}

is denoted as ionization potential depression (IPD). Recent experiments with WDM show an increasing interest in this quantity. Different many‐particle effects contribute to the medium modification of the IPD, see refs .…”

Section: Introductionmentioning

confidence: 99%

Pauli blocking in degenerate plasmas and the separable potential approach

Röpke

2019

Contributions to Plasma Physics

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The Mott effect describes the dissolution of bound states in a dense partially ionized plasma. It occurs when the ionization potential depression, owing to effects of correlation and degeneracy, compensates the binding energy of the bound state. At high densities and moderate temperatures, the Pauli blocking becomes important and influences significantly the degree of ionization in the region of degenerate plasmas. A quantum statistical approach is used where the total density is decomposed in an uncorrelated, “free” part and correlations, as a consequence of the cluster decomposition of the self‐energy. The contribution of correlations to the total density is given by bound states and continuum correlations. Exact solutions for a separable potential are compared to perturbation theory and numerical solutions of the in‐medium Schrödinger equation. The in‐medium scattering phase shifts are evaluated, and the role of continuum correlations is discussed. The Pauli blocking of bound states and the density of states are considered for warm dense matter conditions.

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“…Note that the reduced divergence of the spectrum at lower energies for the dual-section crystal is consistent with the two times lower f-number of the individual crystals. In our NIF scattering experiments 5,6,9 lineouts are taken over a 2 mm high box near the focus of the crystals; therefore the off-axis low-intensity aberrations do not have an impact on the spectral resolution of those measurements. The flat crystal (Fig.…”

Section: Calibration Measurementsmentioning

confidence: 99%

“…3,4 We are developing XRTS for spherical implosion experiments at the National Ignition Facility (NIF). [5][6][7][8][9] In this paper we focus on reporting on further improvements to the Mono Angle Crystal Spectrometer (MACS), which is a highcollection efficiency, gated x-ray spectrometer for XRTS with Zn He α line emission at 9 keV at the NIF. 7 The initial MACS design used a cylindrically curved HOPG (highly oriented pyrolytic graphite) crystal, which focuses the x-rays in the nondispersive axis.…”

Section: Introductionmentioning

confidence: 99%

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

Döppner

Kraus

Neumayer³

et al. 2016

Review of Scientific Instruments

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Upgrades of imaging x-ray crystal spectrometers for high-resolution and high-temperature plasma diagnostics on EASTa) Rev. Sci. Instrum. 85, 11E406 (2014) We are developing x-ray Thomson scattering for applications in implosion experiments at the National Ignition Facility. In particular we have designed and fielded MACS, a high-efficiency, gated x-ray spectrometer at 7.5-10 keV [T. Döppner et al., Rev. Sci. Instrum. 85, 11D617 (2014)].Here we report on two new Bragg crystals based on Highly Oriented Pyrolytic Graphite (HOPG), a flat crystal and a dual-section cylindrically curved crystal. We have performed in situ calibration measurements using a brass foil target, and we used the flat HOPG crystal to measure Mo K-shell emission at 18 keV in 2nd order diffraction. Such high photon energy line emission will be required to penetrate and probe ultra-high-density plasmas or plasmas of mid-Z elements. Published by AIP Publishing.[http://dx

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X-ray scattering measurements on imploding CH spheres at the National Ignition Facility

Cited by 75 publications

References 37 publications

First-principles equation of state and shock compression predictions of warm dense hydrocarbons

First-principles equation of state and shock compression predictions of warm dense hydrocarbons

Pauli blocking in degenerate plasmas and the separable potential approach

Improving a high-efficiency, gated spectrometer for x-ray Thomson scattering experiments at the National Ignition Facility

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