Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, T; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

doi:10.1063/1.4824112

Cited by 8 publications

(5 citation statements)

References 27 publications

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“…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.…”

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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

et al. 2017

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“…Simulations were performed with the widely used 1D multigroup radiation-hydrodynamics code Multi [21][22][23]. The hydrodynamic equations are solved in a Lagrangian formulation with coupled thermal transport, and the laser energy deposition mechanism of inverse bremsstrahlung.…”

Section: Simulation Resultsmentioning

confidence: 99%

Optimization of x-ray emission from under-critical CH foam coated gold targets by laser irradiation

Shang

Zhang

et al. 2016

Nucl. Fusion

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Under-critical CH foam coated gold targets benefit laser-to-x-ray emission because CH plasma inhibits gold plasma expansion, which leads to higher gold plasma density and temperature. Conversely, the CH foam partially absorbs the incident laser energy, which lowers laser absorption into the gold plasma. An analytical model is built to solve the laser collisional deposition fraction in the CH foam layer. The optimization of x-ray emission from under-critical CH foam coated gold targets by laser irradiation is obtained numerically with different CH foam densities and thicknesses. The plasma and x-ray emission properties are investigated. It is found that different CH thicknesses lead to different increase mechanisms for x-ray emission. The x-ray spectrum distributions show that most of the x-ray emission increases occur with photon energy less than 2000 eV.

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“…[1,2] Such an ICF scheme with a late shock is referred to as "shock ignition". [3][4][5][6] The shock ignition is a scheme that is based on the principles of conventional central hot-spot ignition and uses a late shock to augment the compression of the central hot spot above the ignition threshold. The maximum hot-spot pressure is achieved when the outcoming return shock driven by the high central pressure of the collapsing capsule collides, near the inner shell interface, with the incoming ignitor shock launched after the end of acceleration phase.…”

Section: Introductionmentioning

confidence: 99%

Hot-electron deposition and implosion mechanisms within electron shock ignition*

Shang¹,

Che²,

Sun³

et al. 2020

Chinese Phys. B

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A hot-electron driven scheme can be more effective than a laser-driven scheme within suitable hot-electron energy and target density. In our one-dimensional (1D) radiation hydrodynamic simulations, 20× pressure enhancement was achieved when the ignitor laser spike was replaced with a 60-keV hot-electron spike in a shock ignition target designed for the National Ignition Facility (NIF), which can lead to greater shell velocity. Higher hot-spot pressure at the deceleration phase was obtained owing to the greater shell velocity. More cold shell material is ablated into the hot spot, and it benefits the increases of the hot-spot pressure. Higher gain and a wider ignition window can be observed in the hot-electron-driven shock ignition.

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Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

Cited by 8 publications

References 27 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

Optimization of x-ray emission from under-critical CH foam coated gold targets by laser irradiation

Hot-electron deposition and implosion mechanisms within electron shock ignition*

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