Improved Performance of High Areal Density Indirect Drive Implosions at the National Ignition Facility using a Four-Shock Adiabat Shaped Drive

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.

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Status of Indirect Drive ICF Experiments on the National Ignition Facility

10.2172/1248275 ◽

2016 ◽

Author(s):

E. Dewald

Keyword(s):

National Ignition Facility ◽

Indirect Drive

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Polymide Capsules May Hold High Pressure DT Fuel Without Cryogenic Support for the National Ignition Facility Indirect-Drive Targets

Fusion Technology ◽

10.13182/fst97-a30808 ◽

1997 ◽

Vol 31 (4) ◽

pp. 491-496 ◽

Cited By ~ 14

Author(s):

Jorge J. Sanchez ◽

Stephan A. Letts

Keyword(s):

High Pressure ◽

National Ignition Facility ◽

Indirect Drive

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First results of radiation-driven, layered deuterium-tritium implosions with a 3-shock adiabat-shaped drive at the National Ignition Facility

Physics of Plasmas ◽

10.1063/1.4929912 ◽

2015 ◽

Vol 22 (8) ◽

pp. 080703 ◽

Cited By ~ 24

Author(s):

V. A. Smalyuk ◽

H. F. Robey ◽

T. Döppner ◽

O. S. Jones ◽

J. L. Milovich ◽

...

Keyword(s):

Shock Adiabat ◽

National Ignition Facility ◽

First Results

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High-Performance Indirect-Drive Cryogenic Implosions at High Adiabat on the National Ignition Facility

Physical Review Letters ◽

10.1103/physrevlett.121.135001 ◽

2018 ◽

Vol 121 (13) ◽

Cited By ~ 38

Author(s):

K. L. Baker ◽

C. A. Thomas ◽

D. T. Casey ◽

S. Khan ◽

B. K. Spears ◽

...

Keyword(s):

High Performance ◽

National Ignition Facility ◽

Indirect Drive

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Direct drive double shell target implosion hydrodynamics on OMEGA

Laser and Particle Beams ◽

10.1017/s0263034605050330 ◽

2005 ◽

Vol 23 (2) ◽

pp. 187-192 ◽

Cited By ~ 19

Author(s):

GEORGE A. KYRALA ◽

NORMAN DELAMATER ◽

DOUGLAS WILSON ◽

JOYCE GUZIK ◽

DON HAYNES ◽

...

Keyword(s):

Time History ◽

Direct Drive ◽

National Ignition Facility ◽

Initial Stage ◽

Heat Effects ◽

Measured Time ◽

History Of ◽

Indirect Drive ◽

Omega Laser ◽

And Performance

Imploding indirect-drive double shell targets may provide an alternative, non-cryogenic path to ignition at the National Ignition Facility (NIF). Experiments are being pursued at OMEGA to understand the hydrodynamics of these implosions and the possibility of scaling it to the NIF design. We have used 40 beams from the OMEGA laser to directly drive the capsules, and we have used the remaining 20 beams to backlight the imploding shells from two different directions at multiple times. We will review the recent experiments to measure the hydrodynamics of the targets using two-view X-ray radiography of the capsules. We will present data on measured yields from the targets. We will present a measured time history of the hydrodynamics of the implosion. Experiments were pursued using direct drive in which the M-band effect (experienced in the indirect drive experiments) could be eliminated or controlled. It was learned in the direct drive experiments that the best performing capsules were those that had a thin outer layer of gold. This effectively causes M-band pre-heat effects giving implosion hydrodynamics and performance closer to the indirect drive case. We will review the methods used to radiograph the targets and the techniques used to extract useful information to compare with calculations. The effect of imperfections in the target construction will be shown to be minimal during the initial stage of implosion. The yields from the targets were observed to be uniformly low compared to indirect-drive.

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Self-Generated Magnetic Fields in the Stagnation Phase of Indirect-Drive Implosions on the National Ignition Facility

Physical Review Letters ◽

10.1103/physrevlett.118.155001 ◽

2017 ◽

Vol 118 (15) ◽

Cited By ~ 28

Author(s):

C. A. Walsh ◽

J. P. Chittenden ◽

K. McGlinchey ◽

N. P. L. Niasse ◽

B. D. Appelbe

Keyword(s):

Magnetic Fields ◽

National Ignition Facility ◽

Indirect Drive

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Computational investigation of ballistic-impact behavior and penetration resistance of a nacre-like ceramic/polymer laminated composite

International Journal of Structural Integrity ◽

10.1108/ijsi-09-2015-0041 ◽

2017 ◽

Vol 8 (1) ◽

pp. 79-107 ◽

Cited By ~ 2

Author(s):

Mica Grujicic ◽

S. Ramaswami ◽

Jennifer Snipes

Keyword(s):

Critical Role ◽

Laminated Composite ◽

Areal Density ◽

Penetration Resistance ◽

Ballistic Impact ◽

Impact Behavior ◽

Element Analysis ◽

Content Type ◽

Composite Armor ◽

Improved Performance

Purpose Nacre is a biological material constituting the innermost layer of the shells of gastropods and bivalves. It consists of polygonal tablets of aragonite, tessellated to form individual layers and having the adjacent layers as well as the tablets within a layer bonded by a biopolymer. Due to its highly complex hierarchical microstructure, nacre possesses an outstanding combination of mechanical properties, the properties which are far superior to the ones that are predicted using techniques such as the rule of mixtures. Given these properties, a composite armor the structure of which mimics that of nacre may have improved performance over a monolithic armor having a similar composition and an identical areal density. The paper aims to discuss these issues. Design/methodology/approach In the present work, an attempt is made to model a nacre-like composite armor consisting of B4C tablets and polyurea tablet/tablet interfaces. The armor is next tested with respect to impact by a solid right circular cylindrical (SRCC) rigid projectile, using a transient non-linear dynamics finite-element analysis. The ballistic-impact response and the penetration resistance of the armor are then compared with that of the B4C monolithic armor having an identical areal density. Furthermore, the effect of various nacre microstructural features (e.g. surface profiling, micron-scale asperities, mineral bridges between the overlapping tablets lying in adjacent layers, and B4C nano-crystallinity) on the ballistic-penetration resistance of the composite armor is investigated in order to identify an optimal nacre-like composite armor architecture having the largest penetration resistance. Findings The results obtained clearly show that a nacre-like armor possesses a superior penetration resistance relative to its monolithic counterpart, and that the nacre microstructural features considered play a critical role in the armor-penetration resistance. Originality/value The present work indicates that for a given choice of armor material, penetration resistance may be improved by choosing a structure resembling that of nacre.

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

Journal of Fluids Engineering ◽

10.1115/1.4038532 ◽

2017 ◽

Vol 140 (4) ◽

Cited By ~ 2

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.

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