Mixing with applications to inertial-confinement-fusion implosions

Rana, Verinder S.; Lim, Hee Nam; Melvin, Jeremy; Glimm, James; Cheng, Baolian; Sharp, David H.

doi:10.1103/physreve.95.013203

Cited by 17 publications

(6 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, different simulations by [1] showed that the growth of the viscosity coefficient, as the deuterium-tritium plasma heats up to the kinetic regime [2], dissipates the turbulent kinetic energy. It also inhibits the growth of Rayleigh-Taylor or Kelvin-Helmholtz instabilities [3], impacts the mean radial flow [4], and possibly influences the turbulent mixing in the central hot spot, where fusion processes set in [5]. The suddenness of this effect can substantially participate in a local temperature increase by rapidly converting the kinetic energy into an internal one [6].…”

Section: Introductionmentioning

confidence: 99%

Self-similar regimes of turbulence in weakly coupled plasmas under compression

2018

View full text Add to dashboard Cite

Turbulence in weakly coupled plasmas under compression can experience a sudden dissipation of kinetic energy due to the abrupt growth of the viscosity coefficient governed by the temperature increase. We investigate in detail this phenomenon by considering a turbulent velocity field obeying the incompressible Navier-Stokes equations with a source term resulting from the mean velocity. The system can be simplified by a nonlinear change of variable, and then solved using both highly resolved direct numerical simulations and a spectral model based on the eddy-damped quasinormal Markovian closure. The model allows us to explore a wide range of initial Reynolds and compression numbers, beyond the reach of simulations, and thus permits us to evidence the presence of a nonlinear cascade phase. We find self-similarity of intermediate regimes as well as of the final decay of turbulence, and we demonstrate the importance of initial distribution of energy at large scales. This effect can explain the global sensitivity of the flow dynamics to initial conditions, which we also illustrate with simulations of compressed homogeneous isotropic turbulence and of imploding spherical turbulent layers relevant to inertial confinement fusion.

show abstract

Section: Introductionmentioning

confidence: 99%

Self-similar regimes of turbulence in weakly coupled plasmas under compression

2018

View full text Add to dashboard Cite

show abstract

“…Combined instabilities such as the BDI have been shown to be particularly troublesome for ICF; making their elucidation a crucial step for the viability of this technology [12][13][14][15][16][17]. Laser drive asymmetry and fabrication irregularities create perturbations that grow due to combined instability during the initial implosion stage and later on when compressed hot fuel decelerates the colder imploding fuel [15][16][17][18].…”

Section: A Problem Outline and Motivationmentioning

confidence: 99%

“…Furthermore, it has been found that the ICF operating regime is located on a performance cliff, meaning small deviations in model design could have a large impact on performance [12]. This predicament provides impetus to rigorously test the simulations, and their models, used in ICF design as much as possible.…”

Section: A Problem Outline and Motivationmentioning

confidence: 99%

“…The models, theories, and key governing parameters (such as the self-similar growth constants), were mostly developed with planar studies. Because these models and theories have often times not been developed or validated in cylindrical or spherical geometries, they can introduce errors when used in those regimes [12]. The present work addresses this by providing experimental data in cylindrical geometry and a more complex test case for simulations, RMI/RTI models, and theories.…”

Section: B Novelty Of Present Workmentioning

confidence: 99%

See 1 more Smart Citation

Multi-fidelity validation of variable-density turbulent mixing models

Musci¹,

Olson²,

Petter³

et al. 2022

Preprint

View full text Add to dashboard Cite

In this study, ensembles of experimental data are presented and utilized to compare and validate two models used in the simulation of variable density, compressible turbulent mixing. Though models of this kind (Reynolds Averaged Navier-Stokes and Large-Eddy Simulations) have been validated extensively with more canonical flows in previous studies, the present approach offers novelty in the complexity of the geometry, the ensemble based validation, and the uniformity of the computational framework on which the models are tested. Moreover, all experimental and computational tasks were completed by the authors which has led to a tightly coupled experimental configuration with its "digital twin." The experimental divergent-shock-tube facility and its data acquisition methods are described and replicated in simulation space. A 2D Euler model which neglects the turbulent mixing at the interface is optimized to experimental data using a Gaussian process. This model then serves as the basis for both the 2D RANS and 3D LES studies that make comparisons to the mixing layer data from the experiment. RANS is shown to produce good agreement with experimental data only at late flow development times. The LES ensembles generally show good agreement with experimental data, but display sensitivity to the characterization of initial conditions. Resolution dependent behavior is also observed for certain higher-order statistics of interest. Overall, the LES model successfully captures the effects of divergent geometry, compressibility, and combined non-linear instabilities inherent to the problem. The successful prediction of mixing width and its growth rate highlight the existence of three distinct regimes in the development of the instability, each with similarities to previously studied instabilities.

show abstract

“…[ 19,20 ] Therefore, the negative effects of impurities in fuel ignition have always been considered and studied by many researchers. [ 21,22 ] Mixing of the fuel with inactive materials can occur during the compression and hot‐spot formation stages. A cryogenic FI target is designed as a hollow multilayer shell (filled with dilute DT gas) and a hollow cone.…”

Section: Introductionmentioning

confidence: 99%

Effect of inactive impurity ions on deuteron beam‐fusion in fast ignition approach

Khanbabaei

Nazirzadeh

2022

Contributions to Plasma Physics

View full text Add to dashboard Cite

The laser‐generated deuteron beam is a promising scheme for providing the required energy for igniting a pre‐compressed fuel in the fast ignition method in the inertial confinement fusion approach. Deuteron beam provides extra energy through beam‐fusion(BF) reactions during the hot‐spot formation in the pre‐compressed fuel. During the compression and hot‐spot formation stages, Impurities are produced due to the mixing of the fuel with the material of the structural elements of the target. So, the efficiency of BF of the deuteron beam in a spherical deuteron‐triton(DT) fuel in the presence of impurity (such as beryllium, carbon, aluminium, and gold) with arbitrary concentration is investigated. Deuteron beam was considered with Maxwellian energy distribution at a temperature of 3 MeV, which passes through the pre‐compressed contaminated DT fuel with a non‐uniform density profile. It shows that an increase of mixed‐ion charge state and density ratio results in the substantial diminution of the deuteron BF probability, which leads to a reduction in deuteron's extra bonus energy. The effect of fuel temperature on the BF probability in contaminated DT fuel is discussed. Calculations show that increasing the temperature enhanced BF probability.

show abstract

Mixing with applications to inertial-confinement-fusion implosions

Cited by 17 publications

References 58 publications

Self-similar regimes of turbulence in weakly coupled plasmas under compression

Self-similar regimes of turbulence in weakly coupled plasmas under compression

Multi-fidelity validation of variable-density turbulent mixing models

Effect of inactive impurity ions on deuteron beam‐fusion in fast ignition approach

Contact Info

Product

Resources

About