Three dimensional low-mode areal-density non-uniformities in indirect-drive implosions at the National Ignition Facility

2021 ◽  
Vol 28 (4) ◽  
pp. 042708
Author(s):  
D. T. Casey ◽  
O. L. Landen ◽  
E. Hartouni ◽  
R. M. Bionta ◽  
K. D. Hahn ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Areal Density ◽  
National Ignition Facility ◽  
Indirect Drive

scholarly journals Three-Dimensional Design Simulations of a High-Energy Density Reshock Experiment at the National Ignition Facility

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Ping Wang ◽  
Kumar S. Raman ◽  
Stephan A. MacLaren ◽  
Channing M. Huntington ◽  
Sabrina R. Nagel ◽  
...  
Keyword(s):  
Energy Density ◽  
Hydrodynamic Instability ◽  
Three Dimensional ◽  
High Energy ◽  
High Energy Density ◽  
Fluid Interface ◽  
National Ignition Facility ◽  
X Ray Imaging ◽  
Indirect Drive ◽  
Instability Growth

We present simulations of a new experimental platform at the National Ignition Facility (NIF) for studying the hydrodynamic instability growth of a high-energy density (HED) fluid interface that undergoes multiple shocks, i.e., is “reshocked.” In these experiments, indirect-drive laser cavities drive strong shocks through an initially solid, planar interface between a high-density plastic and low-density foam, in either one or both directions. The first shock turns the system into an unstable fluid interface with the premachined initial condition that then grows via the Richtmyer–Meshkov and Rayleigh–Taylor instabilities. Backlit X-ray imaging is used to visualize the instability growth at different times. Our main result is that this new HED reshock platform is established and that the initial data confirm the experiment operates in a hydrodynamic regime similar to what simulations predict. The simulations also reveal new types of edge effects that can disturb the experiment at late times and suggest ways to mitigate them.

Prediction of internal geometry and tensile behavior of 3D woven solid structures by mathematical coding

2021 ◽  
pp. 152808372110013
Author(s):  
Vivek R Jayan ◽  
Lekhani Tripathi ◽  
Promoda Kumar Behera ◽  
Michal Petru ◽  
BK Behera
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Areal Density ◽  
Woven Fabrics ◽  
Tensile Behavior ◽  
Geometrical Parameters ◽  
Fiber Volume ◽  
Acceptable Error ◽  
Internal Geometry ◽  
Unit Cells

The internal geometry of composite material is one of the most important factors that influence its performance and service life. A new approach is proposed for the prediction of internal geometry and tensile behavior of the 3 D (three dimensional) woven fabrics by creating the unit cell using mathematical coding. In many technical applications, textile materials are subjected to rates of loading or straining that may be much greater in magnitude than the regular household applications of these materials. The main aim of this study is to provide a generalized method for all the structures. By mathematical coding, unit cells of 3 D woven orthogonal, warp interlock and angle interlock structures have been created. The study then focuses on developing code to analyze the geometrical parameters of the fabric like fabric thickness, areal density, and fiber volume fraction. Then, the tensile behavior of the coded 3 D structures is studied in Ansys platform and the results are compared with experimental values for authentication of geometrical parameters as well as for tensile behavior. The results show that the mathematical coding approach is a more efficient modeling technique with an acceptable error percentage.

scholarly journals Evidence of Three-Dimensional Asymmetries Seeded by High-Density Carbon-Ablator Nonuniformity in Experiments at the National Ignition Facility

2021 ◽  
Vol 126 (2) ◽  
Author(s):  
D. T. Casey ◽  
B. J. MacGowan ◽  
J. D. Sater ◽  
A. B. Zylstra ◽  
O. L. Landen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
High Density ◽  
National Ignition Facility

scholarly journals Capsule design for the National Ignition Facility

1999 ◽  
Vol 17 (2) ◽  
pp. 217-224 ◽  
Author(s):  
T.R. DITTRICH ◽  
S.W. HAAN ◽  
M.M. MARINAK ◽  
D.E. HINKEL ◽  
S.M. POLLAINE ◽  
...  
Keyword(s):  
Dopant Concentration ◽  
Three Dimensions ◽  
Initial Surface ◽  
National Ignition Facility ◽  
X Ray ◽  
Ongoing Effort ◽  
Surface Finishes ◽  
Material Homogeneity ◽  
Indirect Drive ◽  
Reduced Scale

Several choices exist in the design and production of capsules intended to ignite and propagate fusion burn of the deuterium–tritium (D–T) fuel when imploded by indirect drive at the National Ignition Facility (NIF). These choices include ablator material, ablator dopant concentration and distribution, capsule dimensions, and X-ray drive profile (shock timings and strengths). The choice of ablator material must also include fabrication and material characteristics, such as attainable surface finishes, permeability, strength, transparency to radio frequency and infrared radiation, thermal conductivity, and material homogeneity. Understanding the advantages and/or limitations of these choices is an ongoing effort for LLNL and LANL designers. At this time, simulations in one-, two-, and three-dimensions show that capsules with either a copper-doped beryllium or a polyimide (C22H10N2O4) ablator material have both the least sensitivity to initial surface roughnesses and favorable fabrication qualities. Simulations also indicate the existence of capsule designs based on these ablator materials which ignite and burn when imploded by less than nominal laser performance (900-kJ energy, 250-TW power, producing 250-eV peak radiation temperature). We will describe and compare these reduced-scale capsules, in addition to several designs which use the expected 300-eV peak X-ray drive obtained from operating the NIF laser at 1.3 MJ and 500 TW.

scholarly journals Three-dimensional simulations of low foot and high foot implosion experiments on the National Ignition Facility

2016 ◽  
Vol 23 (5) ◽  
pp. 056302 ◽  
Author(s):  
D. S. Clark ◽  
C. R. Weber ◽  
J. L. Milovich ◽  
J. D. Salmonson ◽  
A. L. Kritcher ◽  
...  
Keyword(s):  
Three Dimensional ◽  
National Ignition Facility ◽  
Three Dimensional Simulations
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