Hot dense matter

Atzeni, S.; Meyer‐ter‐Vehn, Jürgen

doi:10.1093/acprof:oso/9780198562641.003.0010

Cited by 128 publications

(242 citation statements)

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“…1-13 and references therein. In both indirect-and direct-drive laser fusion [1][2][3] such stagnation constitutes the first stage of the hot spot formation, between the convergence of the leading shock wave in the vapor at the target center and the moment when the reflected shock wave reaches the dense shell. 4 The recently proposed impact-ignition approach to the ICF 5 uses thermalization of the kinetic energy of a laseraccelerated plasma in an accretion shock wave as the main mechanism of plasma heating, thereby requiring much higher implosion velocities, ~1000 km/s, than conventional laser fusion.…”

Section: Introductionmentioning

confidence: 99%

“…4 The recently proposed impact-ignition approach to the ICF 5 uses thermalization of the kinetic energy of a laseraccelerated plasma in an accretion shock wave as the main mechanism of plasma heating, thereby requiring much higher implosion velocities, ~1000 km/s, than conventional laser fusion. [1][2][3] Experimental demonstration of plasma heating to fusion temperatures in such stagnation has been reported for spherical 6 and planar 7 geometry.…”

Section: Introductionmentioning

confidence: 99%

“…In the extended family of ideal-gas 1D self-similar solutions describing stagnation in an expanding accretion shock wave, to which the classic Noh solution belongs, the most important one in this respect probably is the Guderley reflected-shock solution, [34][35][36] which closely approximates the early stage of the hot-spot formation in laser fusion targets. [1][2][3][4] This solution involves a partly supported shock wave that, similarly to one produced by a point blast, is slowed down from behind by a rarefaction wave. Therefore it is not clear in advance whether or not it becomes unstable for certain values of gas γ and mode number l , just like the converging-shock Guderley solution is.…”

Section: Introductionmentioning

confidence: 99%

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Stability of stagnation via an expanding accretion shock wave

et al. 2016

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Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy- (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a powerlaw, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydro code verification in two and three dimensions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stability of stagnation via an expanding accretion shock wave

et al. 2016

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“…They were designed to test the acceleration phase hydrodynamic growth predictions used to model these DT layered implosions which achieved fuel areal densities of ∼1.2 g/cm 2 , peak fuel velocities of ∼320-330 km/s and peak radiation temperatures of ∼300 eV [6] . The nominal 209-µm thick CH capsules with nominal 1120-µm outer radii had the same Sidoped layers as used in the previous DT layered implosions and previously published in Ref.…”

Section: Experimental Configurationmentioning

confidence: 99%

“…Hydrodynamic instabilities (including Rayleigh-Taylor and Richtmyer-Meshkov instabilities) and mix play a central role in the performance degradation of spherical implosions in ICF [2,3] . In recent high-compression experiments at the National Ignition Facility (NIF) [4] , the highest fuel areal densities (ρ R) were achieved in implosions with ignitionrelevant implosion velocities [5,6] .…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic instability experiments with three-dimensional modulations at the National Ignition Facility

Smalyuk

Weber

Casey

et al. 2015

High Pow Laser Sci Eng

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The first hydrodynamic instability growth measurements with three-dimensional (3D) surface-roughness modulations were performed on CH shell spherical implosions at the National Ignition Facility (NIF) [G. H. Miller, E. I. Moses, and C. R. Wuest, Opt. Eng. 43, 2841 (2004)]. The initial capsule outer-surface amplitudes were increased approximately four times, compared with the standard specifications, to increase the signal-to-noise ratio, helping to qualify a technique for measuring small 3D modulations. The instability growth measurements were performed using x-ray through-foil radiography based on time-resolved pinhole imaging. Averaging over 15 similar images significantly increased the signal-to-noise ratio, making possible a comparison with 3D simulations. At a convergence ratio of ∼2.4, the measured modulation levels were ∼3 times larger than those simulated based on the growth of the known imposed initial surface modulations. Several hypotheses are discussed, including increased instability growth due to modulations of the oxygen content in the bulk of the capsule. Future experiments will be focused on measurements with standard 3D 'nativeroughness' capsules as well as with deliberately imposed oxygen modulations.

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Effective Potentials for Charge‐Helium and Charge‐Singly‐Ionized Helium Interactions in a Dense Plasma

Ramazanov

Amirov

Moldabekov

2016

Contrib. Plasma Phys.

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The effective electron (proton)-He and electron (proton)-He+ screened pair interaction potentials arising as a result of partial screening of the helium nucleus field by bound electrons, taking into account both screening by free charged particles and quantum diffraction effect in dense plasmas were derived. The impact of quantum effects on screening was analyzed. It was shown that plasma polarization around the atom leads to the additional repulsion (attraction) between the electron (proton) and the helium atom. The method of constructing the full electron (proton)-He and electron (proton)-He + screened pair interaction potentials as the sum of the derived potentials with the polarization potential and exchange potential is discussed.

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Hot dense matter

Cited by 128 publications

References 0 publications

Stability of stagnation via an expanding accretion shock wave

Stability of stagnation via an expanding accretion shock wave

Hydrodynamic instability experiments with three-dimensional modulations at the National Ignition Facility

Effective Potentials for Charge‐Helium and Charge‐Singly‐Ionized Helium Interactions in a Dense Plasma

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