Kinetic physics in ICF: present understanding and future directions

Rinderknecht, H. G.; Amendt, P. A.; Wilks, S. C.; Collins, G. W.

doi:10.1088/1361-6587/aab79f

Cited by 61 publications

(15 citation statements)

References 119 publications

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“…The Euler equations for momentum, mass and energy conservation implicitly assume matter is in thermal equilibrium. In the low-density conditions of the hohlraum, not only are the ions, electrons and photons decoupled with respect to each other, but these particles tend not to be in equilibrium in parts of the hohlraum [20,3,23].…”

Section: Drivementioning

confidence: 99%

Designing radiation transport tests: Simulation-driven uncertainty-quantification of the COAX temperature diagnostic

Fryer¹,

Diaw²,

Fontes³

et al. 2020

High Energy Density Physics

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One of the difficulties in developing accurate numerical models of radiation flow in a coupled radiation-hydrodynamics setting is accurately modeling the transmission across a boundary layer. The COAX experiment is a platform design to test this transmission including standard radiograph and flux diagnostics as well as a temperature diagnostic measuring the population of excitation levels and ionization states of a dopant embedded within the target material. Using a broad range of simulations, we study the experimental errors in this temperature diagnostic. We conclude with proposed physics experiments that show features that are much stronger than the experimental errors and provide the means to study transport models.

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Section: Drivementioning

confidence: 99%

Designing radiation transport tests: Simulation-driven uncertainty-quantification of the COAX temperature diagnostic

Fryer¹,

Diaw²,

Fontes³

et al. 2020

High Energy Density Physics

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“…Kinetic effects 40 within the hohlraum might have sizeable consequences but are still way to complex to take into account in hydro-radiation simulation codes.…”

Section: Introductionmentioning

confidence: 99%

Rayleigh–Taylor mixing may account for the position anomaly in NIF microdot spectroscopy experiments

et al. 2021

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The “microdot spectroscopy” experiment [Barrios et al., “Electron temperature measurements inside the ablating plasma of gas-filled Hohlraums at the National Ignition Facility,” Phys. Plasmas 23, 056307 (2016); Barrios et al., “Developing an experimental basis for understanding transport in NIF Hohlraum plasmas,” Phys. Rev. Lett. 121, 095002 (2018).] allows for a simultaneous measurement of the electron temperature (Te) and position of a patch of Mn and Co inside a Hohlraum, as described by Barrios et al. [“Electron temperature measurements inside the ablating plasma of gas-filled Hohlraums at the National Ignition Facility,” Phys. Plasmas 23, 056307 (2016).] HYDRA simulations systematically predicted a dot location further away from its starting location than observed in the experiment. In the article, integrated radiation hydrodynamics simulations with TROLL have led to the same trend as HYDRA. A new ad hoc treatment of laser absorption, through what we have called absorption multipliers, has been implemented in TROLL in order to mimic the effect of absorption mechanisms other than inverse-bremsstrahlung. It led to the instrumental conclusion that whatever physical phenomenon was responsible for the position anomaly must have occurred in the early stage. More precise simulations of the dot region, from early to late time, show that the position discrepancy can be explained by a Rayleigh–Taylor mixing of the dot into the ablator as it expands in the Hohlraum. This mixing tends to shift the simulated dot closer to the location measured in the experiment. However, the mixing also changes the interpretation of the electron temperature from the spectral line ratios.

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“…Numerical modeling of compressible multiphase flow have found many applications in various natural, industrial and technological areas. Typical applications include bubble dynamics [52,51], underwater explosion [45,31,27,74], cavitation flows [39,63,62], multiphase flows in the porous rock [8], inertial confinement fusion [77,53], Rayleigh-Taylor [66,38,78] and Richtmyer-Meshkov instabilities [35,9,86] and so on. In some problems where steep distributions of flow parameters occur, diffusion processes such as the heat conduction and viscous stress may have significant impact.…”

Section: Introductionmentioning

confidence: 99%

Diffuse interface relaxation model for two-phase compressible flows with diffusion processes

Zhang,

Menshov,

Wang

et al. 2021

Preprint

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The paper addresses a two-temperature model for simulating compressible two-phase flow taking into account diffusion processes related to the heat conduction and viscosity of the phases. This model is reduced from the two-phase Baer-Nunziato model in the limit of complete velocity relaxation and consists of the phase mass and energy balance equations, the mixture momentum equation, and a transport equation for the volume fraction. Terms describing effects of mechanical relaxation, temperature relaxation, and thermal conduction on volume fraction evolution are derived and demonstrated to be significant for heat conduction problems. The thermal conduction leads to instantaneous thermal relaxation so that the temperature equilibrium is always maintained in the interface region with meeting the entropy relations. A numerical method is developed to solve the model governing equations that ensures the pressure-velocitytemperature (PVT) equilibrium condition in its high-order extension. We solve the hyperbolic part of the governing equations with the Godunov method with the HLLC approximate Riemann solver. The non-linear parabolic part is solved with an efficient Chebyshev explicit iterative method without dealing with large sparse matrices. To verify the model and numerical methods proposed, we demonstrate numerical results of several numerical tests such as the multiphase shock tube problem, the multiphase impact problem, and the planar ablative Rayleigh-Taylor instability problem.

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Kinetic physics in ICF: present understanding and future directions

Cited by 61 publications

References 119 publications

Designing radiation transport tests: Simulation-driven uncertainty-quantification of the COAX temperature diagnostic

Designing radiation transport tests: Simulation-driven uncertainty-quantification of the COAX temperature diagnostic

Rayleigh–Taylor mixing may account for the position anomaly in NIF microdot spectroscopy experiments

Diffuse interface relaxation model for two-phase compressible flows with diffusion processes

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