DOE/NA-0044

2016 Inertial Confinement Fusion
Program Framework Ten-Year High Energy-Density Science Strategic Plan
 Integrated Experimental Campaigns
 Priority Research Directions
 National Diagnostics Plan On the CoverThe Inertial Confinement Fusion (ICF)
Program’s mission is to provide themost extreme temperature and pressure
conditions spanning states of condensed
matter to very hot and dense plasmas for the
National Nuclear Security Administration’s Stockpile
Stewardship Program.
This mission requires some of the most advanced
experimental and computational capabilities in the world.
Most important to the success of this mission are the highly
trained scientists, engineers, and technicians that dedicate
their lives to this mission, and are a key part of theintellectual capital that underpins the nuclear
weapons stockpile.
Pictured on the cover are major components,
experiments, computations, and people
from a variety of facilities and facets of
the ICF Program that are describedin more detail in this document.

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government
nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors or their employees, makes any warranty, express
or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or any third party’s use or the results of such useof any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference
herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily
constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof or its contractors or
subcontractors. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or
any agency thereof.
The U.S. Government retains a nonexclusive, royalty-free license in and to any copyright covering this publication.

DOE/NA-0044

2016 Inertial Confinement Fusion
Program Framework Ten-Year High Energy-Density Science Strategic Plan
 Integrated Experimental Campaigns
 Priority Research Directions
 National Diagnostics Plan

Department of Energy

National Nuclear Security Administration
Washington, DC 20585

May 11, 2016

MEMORANDUM FOR NNSA’S HIGH ENERGY DENSITY PHYSICS AND
INERTIAL CONFINEMENT FUSION COMMUNITYFROM:

KEITH R. LECHIENDIRECTOROFFICE OF INERTIAL CONFINEMENT FUSIONSUBJECT:

2016 Inertial Confinement Fusion Program Framework

It is a pleasure to present the first-ever comprehensive national Inertial Confinement Fusion(ICF) Program Framework.  This Framework was developed over 20 months using input fromhundreds of technical staff, program managers, and academic partners from over a dozen
institutions with direct interest in the ICF and related high energy density (HED) aspects of
National Nuclear Security Administration’s (NNSA) Stockpile Stewardship Program (SSP).
In the January 2015 Directors’ letter on the importance of the SSP’s ICF and HED efforts, thethree NNSA Laboratory Directors pledged their delegates to “[meet] regularly in 2015 to ensure
progress towards [an] integrated and coordinated National HED effort.”  This Framework is the
product of those efforts, and this document summarizes the Framework with reference to a morecomprehensive description connected to the program requirements and plans.  The document
will be revised annually with each Framework element updated as needed.
Over the last two years, there have been numerous technical achievements in the HED/ICF
portfolio.  Record neutron yields have been demonstrated on the National Ignition Facility (NIF)
and the Z facility, and record hot spot pressures have been achieved at the OMEGA laser.
Innovative ramp compression experiments for diamond at the NIF were highlighted in a coverarticle in Nature.  The seventeenth plutonium experiment was executed on Z to study shocklessloading at low pressure in order to span the full equation-of-state phase space.  The lattice
structure of plutonium under extreme pressure and temperature conditions was observed on the
NIF.  In 2015, researchers at NIF made dramatic improvements in efficiency, exceeding 350
shots in support of stockpile stewardship and, at Rochester, a record 25,000th shot was
conducted on the OMEGA laser.  New neutron and x-ray sources are being developed to support
the qualification of components of stockpile systems in hostile environments for life extension
programs.  
Today, an unprecedented level of collaboration is occurring in the ICF Program.  Scientists
from Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratories (SNL),
Los Alamos National Laboratory (LANL), the University of Rochester’s Laboratory for Laser
Energetics (LLE), and the Naval Research Laboratory (NRL), along with researchers in private

industry and academia, are collaborating on diagnostic development, code development, datainterpretation and analysis, and facility improvements.  For example, LANL, LLNL, SNL, andLLE scientists, together with their academic partners, have established a national working groupto study ICF hot spot characteristics at stagnation for all three ignition approaches. SNL, LLNL,
General Atomics, and LLE are developing advanced cameras that push the state of the art inorder to “make movies” that will enable scientists to explore the evolution of ICF implosions
in exquisite detail.  LLNL, LLE, SNL, and LANL are developing code capabilities for each site
to improve the level of peer review among the laboratories.  NRL and LLE regularly conduct
experiments using special target design techniques that will reduce implosion instabilities.  Theproductivity and the depth of these collaborations have improved exponentially over the last two
years, which will yield many benefits over the coming years.
A comprehensive program review of the HED/ICF portfolio was executed from May to October
2015. Nearly 40 “next steps” were identified that included delivery of eight transformational
diagnostics by 2021, doubling the number of Z experiments to support magnetic direct drive by
2019, reprioritizing academic program investments, and developing cross-platform validation
capabilities to study the physics of ICF hot spot formation and stagnation.
The ICF Program has developed a goal that, by 2020, we will determine the efficacy of reaching
ignition on the NIF and of achieving credible physics scaling to multi-megajoule fusion yields
for each of the three major ICF approaches.  The program of work to achieve this goal isdescribed in this Framework document.  The ICF Program has also developed Devil’s Advocate
Red Teams, which are groups of subject matter experts embedded in the ICF Program whose
purpose is to challenge the technical assumptions and direction of the Program as it pursues the2020 goal.
Mission needs for stockpile stewardship are evolving, and the HED/ICF portfolio strives to stayahead of the need curve.  NNSA is evaluating the science and technology needs associated withexperimentally probing boost-related physics; developing high-fidelity dynamic materials
science platforms for hazardous materials for a number of missions; probing threat-relevant
outputs, environments, and effects regimes that may impact nuclear survivability requirements;
creating and applying multi-megajoule fusion yields; and training weapons designers and testing
their understanding of physics in regimes relevant to secondary performance.
Finally, a special thank you to the Federal and laboratory program leadership who havededicated months of their lives, thousands of miles of travel and, many nights away from home
to bring the Framework together.

This national ICF Program Framework document summarizes the integrated plans and sharedgoals of the Program for 2016 and subsequent years, as envisioned in the NNSA Laboratory
Directors’ January 2015 letter to DOE Under Secretary for Nuclear Security Frank G. Klotz.  Ourefforts over the last 20 months to coordinate national HED/ICF research activities have been
fruitful.  As delegates of the Laboratory Directors and as the Director of the Laboratory for Laser
Energetics, we will continue to work together to ensure HED/ICF efforts remain of high impact to
the Nation’s Stockpile Stewardship Program.

Charles P. Verdon
Principal Associate Director for Weapons & Complex Integration
Lawrence Livermore National Laboratory

Robert B. Webster
Principal Associate Director of Weapons Program
Los Alamos National Laboratory

J. Stephen Rottler
Deputy Laboratories Director andExecutive Vice President, National Security Programs
Sandia National Laboratories

Robert L. McCrory
Vice President, University of Rochester
Director and CEO
Laboratory for Laser Energetics Contents
Acronyms and Abbreviations.......................... vi

1

Overview

1.1
1.2

Background...........................................
Summary of the ICF Program
Framework............................................
1.3
Summary of the Three Major ICF
Approaches............................................
1.3.1 Overview of Laser Indirect Drive........
1.3.2 Overview of Laser Direct Drive............
1.3.3 Overview of Magnetic Direct Drive.....
1.3.4 Overview of Target Fabrication
Activities................................................
1.4
Framework Document Summary........

2
3
4
4
5
5
6
6

2

The Ten-Year High Energy Density
Science Strategic Plan

2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4
2.3

Background........................................... 8
Key Technical Focus Areas................... 9
Nuclear................................................... 9
Thermonuclear...................................... 9
Radiation Transport............................. 10
Outputs, Environments, and Effects... 10
Summary............................................... 10

3Integrated Experimental Campaigns

3.1
3.1.1

Laser Indirect Drive.............................. 14
Phases of the Laser Indirect Drive
IECs........................................................ 14
3.1.1.1 Phase 1 (FY 2016  -FY 2017).................. 14
3.1.1.2 Phase 2 (FY 2017-FY 2018).................. 15
3.1.1.3 Phase 3 (FY 2019-FY 2020)................. 15
3.1.2 Detailed 2016 Activities........................ 16
3.2
Laser Direct Drive................................. 18
3.2.1 Phases of the Laser Direct Drive..........
IECs........................................................ 18
3.2.1.1 Phase 1: Develop Capabilities for High
Performance Implosions on
OMEGA................................................. 19
3.2.1.2 Phase 2: Develop and Test Strategies
to Mitigate and Control Laser-Plasma
Instabilities............................................ 19
3.2.1.3 Phase 3: Advance Modeling and Test theLimits of 1D Physics and3D Predictions....................................... 19
3.2.1.4 Phase 4: Test of Integrated Target
Performance.......................................... 20
3.2.2 Detailed 2016 Activities........................ 20
3.3
Magnetic Direct Drive........................... 23
3.3.1 Phases of the Magnetic Direct Drive
IECs........................................................ 23
3.3.1.1 Phase 1 (FY 2016-FY 2018).................. 23
3.3.1.2 Phase 2 (FY 2018-FY 2020)................. 24
3.3.2 Detailed 2016 Activities........................ 25

4

The Priority Research Directions

4.1
4.1.1

Laser Indirect Drive.............................. 28
Driver-Target Coupling........................ 28

National Nuclear Security Administration

4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.2.6
4.3
4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.3.6

Target Preconditioning......................... 30
Implosion............................................... 30
Stagnation and Burn............................. 30
Intrinsic and Transport Properties...... 32
Modeling, Approximations, andValidation.............................................. 32
Laser Direct Drive................................. 32
Driver-Target Coupling........................ 32
Target Preconditioning......................... 32
Implosion............................................... 33
Stagnation and Burn............................. 33
Intrinsic and Transport Properties...... 35
Modeling, Approximations, andValidation.............................................. 35
Magnetic Direct Drive........................... 35
Driver-Target Coupling........................ 35
Target Preconditioning......................... 36
Implosion............................................... 36
Stagnation and Burn............................. 36
Intrinsic and Transport Properties...... 38
Modeling, Approximations, andValidation.............................................. 38

5

National Diagnostics Plan

5.1
5.2
5.3

Transformational Diagnostics............. 40
Broad Diagnostics................................. 44
Local Diagnostics.................................. 46

6

Scientific Peer Review and Achieving
the 2020 ICF Program Goal

6.1
6.2

Overview................................................ 48
Measuring Progress Toward the2020 Goal.............................................. 48
6.3
Specific Needs to Support PhysicsScaling Arguments Associated withthe 2020 Goal........................................ 49
6.3.1 Laser Indirect Drive.............................. 49
6.3.2 Laser Direct Drive................................. 50
6.3.3 Magnetic Direct Drive........................... 51
6.4
Establishing Devil’s Advocate Red
Team to Continuously Evaluate
Progress Toward the 2020 Goal.......... 52

7
7.1
7.2
7.3

ICF-HED Capabilities and the
Next 20 Years of Stockpile
Stewardship

3

9

20

30

Summary of Existing Capability Needs for
ICF/HED............................................... 54
Changes in the Nuclear Security
Environment That Affect Current
Thinking................................................ 54
Summary of ICF/HED-Related SSP
Needs for the Next 20+ Years.............. 5542v

 Acronyms and Abbreviations
1D		
2D		
3D		

one-dimensional
two-dimensional
three-dimensional

ARPA-E Advanced Research Projects Agency-Energy
ARS/X-1 Advanced Radiation Source

LPSE
LTE

Laser Plasma Simulation Environment
local thermal equilibrium

MA		
MagLIF
MCP
MDD
MeV
MIT

megaamperes
Magnetized Liner Inertial Fusion
micro-channel platemagnetic direct drive
mega electron volt
Massachusetts Institute of Technology

NDP
NDWG
NIF
NIS		
NISP
NLTE
NLUF
NNSA
NRL
nTOF
NTD

National Diagnostics Plan
National Diagnostics Working Group
National Ignition Facility
Neutron/Gamma Imaging
National Implosion Stagnation Physics
non-local thermal equilibrium
National Laser Users’ Facility
National Nuclear Security Administration
Naval Research Laboratory
neutron time of flightneutron temporal diagnostic

OTS

optical Thomson scattering

Be		
BR		

beryllium
magnetization

CBET
CBI		
CCD
CCR
CEA
CH		
CR		

cross-beam energy transfer
Curved Backlighting Imager
charge-coupled device
case-to-capsule ratio
Commissariat a l’Energie Atomiqueplastic
convergence ratio

D		
DART
DOE
DRACO
dsr		
DT 		

deuterium
Devil’s Advocate Red Team
Department of Energy
University of Rochester’s radiation transport code
down scatter ratio
deuterium-tritium

EOS

equation of state

PDD
PRD

polar direct drive
Priority Research Direction

GA
GCD

General Atomics
gamma spectroscopy

RDT&E
RKE

Research, Development, Test & Evaluation
Residual Kinetic Energy

HDC
HED
HEDP
HEPP
HYDRA
		

high-density carbon
high energy density
high energy density physics
high explosive pulsed power
Lawrence Livermore radiation hydrodynamics
code

SBS		
SLOS
SNL
SRS		
SSAP
SSMP
SSP

stimulated Brillouin scattering
single line of sight
Sandia National Laboratories
stimulated Raman scattering
Stewardship Science Academic Programs
Stockpile Stewardship and Management Plan
Stockpile Stewardship Program

ICF
IEC		
IFH

inertial confinement fusion, Inertial Confinement
Fusion & High Yield (Program)
Integrated Experimental Campaign
intermediate fill hohlraum

keV		
kJ		
Kr		

kilo electron volt
kilojoulekrypton

T		
Ti		
TN 		
TPD
TRL

tritium
ion temperaturethermonuclear
two-plasmon decay
Technical Readiness Level

LANL
LDD
LID		
LLE
		
LLNL
LPI		

Los Alamos National Laboratory
laser direct drive
laser indirect drive
University of Rochester Laboratory for Laser
Energetics
Lawrence Livermore National Laboratory
laser-plasma instabilities

V&V
VISAR

validation and verification
Velocity Interferometer System for Any 			Reflector

FY

fiscal yearZ		

Z Machinevi

National ICF Program Framework Overview

1

1.1

“The principal goal of the
ICF Program by 2020 is todetermine the efficacy of NIF
for achieving ignition and thecredible physics scaling tomulti-megajoule fusion yields
for each of the major ICF
approaches.”

Background

The Inertial Confinement Fusion and High Yield (ICF) Program supports themission of the U.S. Department of Energy (DOE)/National Nuclear Security
Administration (NNSA) to maintain a safe, secure, and effective nuclear
deterrent by creating experimentally diagnosable platforms that accessextreme temperature, pressure, and density regimes relevant to nuclear
weapons performance. The overwhelming majority of the yield from a nuclear
weapon is generated in this high energy density (HED) state. Expertisein HED science is therefore a core technical competency of the Stockpile
Stewardship Program (SSP). The ICF Program supports experiments andfacilities that generate weapon-relevant HED conditions in specializedlaboratory environments, in the absence of nuclear weapons explosive
testing. Conducting such experiments requires the development of advanced
experimental and computational tools, diagnostics, and technologies suchas state-of-the-art laser and pulsed power platforms. The ICF Program
collaborates with NNSA’s Science Program which sets the programmatic
direction for weapons-relevant HED efforts.
U.S. nuclear weapons are certified, assessed, and modified by a highly trained
workforce, on the basis of simulations and experiments. Models for material
properties at extreme pressures, temperatures, and densities inaccessible
outside of HED laboratory facilities are used as inputs to simulation tools.
Executing successful laboratory experiments exercises the judgement ofscientists and engineers, the models they use, and their ability to diagnose
thermonuclear (TN) processes relevant to weapons design. The ICF Program
contributes to the SSP in the following areas:(a) Challenging and developing nuclear weapons designers in HED regimes
not otherwise accessible without nuclear weapons explosive testing; Validating models for the properties of HED materials used insimulation tools;
 Developing high-fidelity diagnostics, advanced experimental platforms,
and predictive capabilities and simulations in HED regimes; Creating and applying multi-megajoule fusion yield for assessment of
nuclear weapons performance and survivability; and

(b)

(c)

Figure 1-1. (a) The NIF final optics
assembly, (b) the Z facility, and (c)the OMEGA laser.
2

 Providing opportunities for academic users to push the state of the art
in HED science to the mutual benefit of NNSA’s mission.
The ICF Program has clear SSP drivers for studying the properties of robust
TN burning plasmas, pursuing multi-megajoule fusion yields (which require
ignition), and ultimately pursuing high yield. The ICF Program’s principal
mission since its inception in the early 1960s is to deliver the capabilities
and platforms to create and study these conditions. Since the early 1990s,
the program has delivered these capabilities in a controlled laboratoryenvironment. Accomplishing that monumental scientific and engineering
challenge has required some of the most advanced technologies and facilities
ever constructed. Today, the principal goal of the ICF Program by 2020 is
to determine the efficacy of the National Ignition Facility (NIF) for achieving
ignition and the credible physics scaling to multi-megajoule fusion yields foreach of the major ICF approaches.
Most experiments are performed at NNSA’s three major HED facilities: the
NIF at Lawrence Livermore National Laboratory (LLNL), the Z facility at
Sandia National Laboratories (SNL), and the Omega Laser Facility (OMEGA)
at the University of Rochester’s Laboratory for Laser Energetics (LLE) (seeFigure 1-1). The ICF Program includes contributions from the Naval Research
National ICF Program Framework Overview

Laboratory (NRL) (see the NIKE laser in Figure 1-2), the Los Alamos National
Laboratory (LANL), industry partners in target fabrication (see Figure 1-3),
as well as multiple academic institutions supported by the joint program inHigh Energy Density Laboratory Plasmas with DOE’s Office of Fusion Energy
Sciences.

1.2

Summary of the ICF Program Framework

To achieve its 2020 goal, the ICF Program has developed an integrated
program framework. This framework was principally motivated by four needs.
1.

The post-National Ignition Campaign ICF Program needed a clear fiveyear goal to understand if ignition may be achieved on the NIF (and if
not, why not); and, although Z and OMEGA were not built to achieve
ignition, these facilities are home to two of the three major approaches
to ignition. Therefore, a science program was needed that could explore
physics scaling arguments to fusion yield for the approaches and as ameans to compare the approaches.

2. The distinction between focused physics experiments and integrated
performance experiments needed to be clearly delineated to enable
scientific debate regarding the balance between them, given the state ofunderstanding and fixed facility resources.

Figure 1-2. The Nike laser focusingarray.

3. The visibility into program activities needed to be increased to enhancescientific peer review within and among the laboratories, and to subject
those activities to healthy criticism from institutions outside of thelaboratories in an effort to strengthen the scientific foundation of the
ICF Program and the basis for program decision making.
4. Clear milestones, metrics, and deliverables needed to be establishedthat may be achieved for transparency during the intervening years andto track progress.
The Framework was structured into four major elements:
 The Ten-Year High Energy Density Science Strategic Plan. This
fundamental requirements document outlines the three-, five-, and10-year deliverables for the HED weapons science portfolio, including
the major ICF Program deliverables. Requirements are derived from theannual 25-year Stockpile Stewardship and Management Plan (SSMP)
and from the emerging stockpile responsiveness requirements in the
National Defense Authorization Act for Fiscal Year 2016.

(a) The Integrated Experimental Campaigns (IECs). This element involves
an approach-specific set of implosion experiments with the primaryobjective to baseline performance, demonstrate scaling, test new design
features or capabilities, and/or test new target concepts. Performance
metrics are highly integrated quantities such as total neutron yield, andmilestones are generally spread over multiple years.
 The Priority Research Directions (PRDs). This element involves
fundamental and focused research to develop and improve models,codes, and simulations (i.e., predictive capabilities), and to set detailed,physics-based milestones for experimental research and computational
efforts. The PRDs are designed to enable cross-cutting coordination andbasic research opportunities for external collaborations.

(b)
Figure 1-3. (a) A NIF cryogenic
ignition target and (b) an OMEGA
capsule.

 The National Diagnostics Plan. This resource-loaded plan describes a
suite of advanced diagnostics to be delivered through 2021 that are costshared among LLNL, LANL, SNL, LLE, and NRL. The plan includes
contributions from 17 institutions.

National Nuclear Security Administration

3

Figure 1-4. The PRDs and the IECs
are linked through modeling andsimulation. Each is needed to achieve
the 2020 ICF Program goal.

“The ICF Program Framework
is critical to ensuring that our
Nation continues to lead andplay a vibrant role within the
HED community.”Like other activities within the SSP, the focused physics experiments in the
PRDs and the integrated performance experiments of the IECs are linked
closely through modeling, code, and simulation efforts. First and foremost,the PRDs serve as validation experiments that underpin models in codes thatare used for IEC design and performance prediction. IEC experiments also
serve as validation experiments. Figure 1-4 shows the relationship between the
PRDs and IECs through modeling and simulation.
The United States has maintained a strong leadership role in ICF and HED
since the development of HED drivers based on megajoule-class lasers andpulsed power. However, the field of research is increasingly international inscope with major facilities built, planned, or under construction worldwide.
Notable examples of other major inertial fusion research facilities include theLaser Mégajoule (LMJ) in France, the FIREX Laser in Japan, the SG-III laser
and PTS pulsed power facilities in China, the Vulcan and Orion Lasers in the
United Kingdom, and numerous smaller facilities in countries such as Russia,
India, Poland, the Czech Republic, and Iran. Like the United States, some ofthese countries are interested in pursuing multi-megajoule fusion yields using
approaches similar to those described here. The ICF Program Framework is
critical to ensuring that our Nation continues to lead and play a vibrant role
within the HED community.
A summary of the major U.S. ICF approaches pursued today is provided in thenext section.

1.3

Summary of the Three Major ICF Approaches

The major ICF approaches are: Laser Indirect Drive led by LLNL and primarily executed at NIF,
 Laser Direct Drive led by LLE and primarily executed at the OMEGA
laser, and Magnetic Direct Drive led by SNL and primarily executed at the Z
facility.
1.3.1
Figure 1-5. The NIF hohlraum
converts 192 beams of laser light to
x-rays that implode the capsule.

4

Overview of Laser Indirect Drive

Laser indirect drive (LID), also referred to as laser x-ray drive, is pursued
at the NIF. NIF’s 192 laser beams inject approximately 1.8 megajoules oflaser energy into a cylindrical gold-lined cavity about 1 centimeter long (seeFigure 1-5), called a “hohlraum” (German for an empty room). The beams
rapidly produce a thermal x-ray source in the hohlraum. The deuteriumNational ICF Program Framework Overview

tritium (DT) fuel is in a solid layer about the thickness of a human hair on theinside surface of a 2-millimeter-diameter spherical capsule at the hohlraum
center. X-rays from the hohlraum vaporize, or ablate, the capsule surface,
generating pressures approaching 100 megabars that implode the fuel atnearly 400 kilometers per second. The implosion compresses the fuel by afactor of 30, amplifying the pressure by precision pulse shaping to several
hundred gigabars and heating a central “hot spot” of DT. The LID goal is todetermine the efficacy of the NIF to achieve ignition and, if this is found to
be improbable, to understand the reasons why. Visit https://lasers.llnl.gov/
about/what-is-nif for more information.
1.3.2







Overview of Laser Direct Drive

Laser direct drive (LDD) couples the laser energy directly to the capsulesurface. OMEGA has 60 symmetrically arranged beams that focus up to
30 kilojoules on the capsule to produce symmetric implosions (see Figure 1-6).
Tailoring the laser profile generates up to 140 megabar pressures at thecapsule surface. The primary LDD challenge is ensuring each laser beam issufficiently smooth (i.e., the intensity variation across the beam is small) andthe number of beams is sufficient to minimize nonuniformities caused by beam
overlap. Beam smoothing techniques developed over the past two decades
at LLE have ensured the drive uniformity rivals that with x-ray drive in ahohlraum. Tailoring the laser intensity temporal profile reduces the growthrate of perturbations at the ablating capsule surface. Because LDD is predicted
to couple 5-10 times more energy into the hot spot than LID (for the same
incident laser energy), the fuel mass can be increased, reducing the ignition
threshold hot spot pressure by roughly a factor of three to 120-140 gigabars.
LDD ignition is predicted to occur at fuel compressions of 22-25. Maximizing
the energy absorption in the target and thus the imploded mass is a major LDD
goal. The OMEGA laser was not designed to achieve ignition, but LDD researchat sub-scale will inform decisions regarding the path to ignition. Visit http://
www.lle.rochester.edu/directorsoffice.php for more information.
1.3.3

A goal of LID is todetermine the efficacyof the NIF for achieving
ignition. Visit https://lasers.
llnl.gov/about/what-is-nif for
more information.

Overview of Magnetic Direct Drive

Magnetic direct drive (MDD) refers to using large electrical currents, and theresulting magnetic field, to compress the fuel directly to the conditions forfusion. The primary facility for studying this approach is the Z pulsed power
facility at SNL. Z stores approximately 20 megajoules in its capacitor banks.
That energy is compressed in space and time to produce a peak current of
up to 26 megaamperes. This large current is passed through a cylindricalliner containing the DT fuel that creates a strong magnetic field and results
in a radially inward force that compresses and heats the DT (see Figure 1-7).
Prior to the compression, a laser heats a thin column of the fuel and a seedmagnetic field is added, reducing heat conduction losses from the laserheated fuel during the compression. Calculations suggest that when certain
conditions are satisfied, charged particles produced by the DT reactions

Figure 1-6. A cryogenic DT implosion
inside the 60-beam OMEGA target
chamber at LLE, where most LDDrelevant research is conducted.

A goal for LDD is todemonstrate greater than
100-gigabar hot-spot pressure
on OMEGA. Visit www.lle.
rochester.edu for more
information.
Figure 1-7. The liner on Z is roughly
the size of a thimble. The goal of the
MDD effort is to radiate 100-kilojoule
DT-equivalent neutrons from thistarget.

National Nuclear Security Administration

5

A goal of MDD is todemonstrate 100-kilojoule
DT equivalent yields on Z.
Visit http://www.sandia.
gov/Pulsed-Power/res-areas/
inertialconfinement/index.
html for more information.
heat the fuel further and are confined to helical orbits, reducing the fuelcompression requirements. The goal is to demonstrate 100-kilojoule (kJ) DT
equivalent yields on Z. The Z was not designed to achieve ignition, but MDD
research at sub-scale will inform decisions regarding the path to ignition. Visit
http://www.sandia.gov/Pulsed-Power/res-areas/inertialconfinement/index.
html for more information.
1.3.4

Overview of Target Fabrication Activities

Every HED experiment for ICF requires a specialized “target,” the physicalexperimental package that is under investigation (see Figure 1-8). Theenergy delivered to a target can create temperatures greater than the core of
the Sun and pressures greater than the core of the Earth to allow scientists
to study the physics of HED plasmas. Many ICF target experiments requirehydrogen fuel to be frozen at 20 degrees Kelvin to achieve the high fueldensities after compression needed for ignition, TN burn, and high fusionenergy gain. Targets and target components are primarily supplied by two
industry partners, General Atomics (GA), http://www.ga.com/ift-role andSchafer Corporation, http://www.schafercorp.com/laboratories/livermore/.
NNSA also provides support to industry partners and the development andfabrication of the engineering systems for filling, transport, and the insertionof cryogenic targets.

1.4

Framework Document Summary

This document summarizes the key components of the ICF Program
Framework. It emphasizes the technical program to achieve robust TN burning
plasmas in the laboratory. Facility operations, governance, and the detailsof the support of other stockpile stewardship activities are covered in otherprogram management documents.

Figure 1-8. A NIF hohlraum target.

This document summarizes
the key components of the
ICF Program Framework
as compared to morecomprehensive documentationof requirements and plans.


6





The primary audience for this document is three distinct groups, all withfamiliarity of the scientific mission of the ICF Program. First, the document
is for the hundreds of scientists, engineers, and technicians—the stockpile
stewards—who work every day on perhaps one approach or aspect of the
ICF Program, but maintain a technical interest or may have something tocontribute to another aspect to the program into which they presently haveno visibility. Second, it is for the laboratory and Federal leadership andmanagement: (a) to agree on the priorities and plans for the coming years,
and (b) to gain an appreciation of the technical challenges and the breath ofactivities across the ICF Program. Third, and quite importantly, the document
is for external stakeholders (e.g., Congress, Department of Defense, academia,etc.) to see that the comprehensive management structure of today’s ICF
Program has clear deliverables, milestones, and metrics and that the
Framework enables the ICF Program to set priorities for future investments.
The Framework document will be updated annually. ICF Program leadershipis working several additional program areas in anticipation of next year’s
update. These include: 1) next generation computer codes tailored to plasmaand HED environments that fully utilize evolving computer architectures;2) extension of national Working Groups into other technical areas suchas laser-plasma interactions; 3) assessing the worldwide ICF landscapeand understanding international competitiveness; 4) establishment of“traineeships” in specific fields of critical importance such as atomic physics
and spectroscopy; and 5) conceptualizing a laboratory basic science program
for the NIF and Z.

National ICF Program Framework The Ten-Year High Energy Density

Science Strategic Plan2

2.1
From the U.S. Department of Energy
Strategic Plan 2014-2018, March2014 (page 13)
Goal 2: Nuclear Security
Strengthen national security by
maintaining and modernizing thenuclear stockpile and nuclear security
infrastructure, reducing global
nuclear threats, providing for nuclear
propulsion, improving physical andcybersecurity, and strengthening key
science, technology, and engineering
capabilities
Strategic Objective 4 – Maintain thesafety, security and effectivenessof the nation’s nuclear deterrent
without nuclear testing

Background

The U.S. Department of Energy’s 2014-2018 Strategic Plan (March 2014)
cites a strategic objective to maintain the safety, security, and effectivenessof the Nation’s nuclear deterrent without nuclear testing. NNSA’s Defense
Programs support this objective by performing experimental and theoreticalresearch in the HED regime, which reaches the most extreme conditions
possible in the laboratory. This research and the associated facilities aresupported by the ICF and Science Programs within NNSA’s Research,
Development, Test, and Evaluation (RDT&E) portfolio.
In December 2014, the three NNSA Laboratory Directors, senior staff of thelaboratories, and the LLE leadership defined decadal mission drivers for
the HED/ICF program in support of the SSP. The Directors codified thesemission drivers in a January 2015 letter to the DOE Under Secretary for
Nuclear Security (see Figure 2-1). These five mission drivers are: Test weapon designers in HED experimental design; Access material pressure and density regimes that are inaccessible via
other experimental techniques; Generate and use TN burning plasmas;
 Develop commensurate high-fidelity diagnostics and experimental
platforms; and Create and apply multi-megajoule fusion yields.

Figure 2-1. Letter signed by the three
NNSA Laboratory Directors in which
the mission drivers for the HED/ICF
program in support of the SSP are
codified.

8

National ICF Program Framework The Ten-Year HED Science Strategic Plan

With these mission drivers in mind, a 10-year HED Science Strategic Plan
was developed (National HED Strategy (U),” Document No. LLNL COPD2015-0003, LANL LA-CP-15-00064, January 2015). The plan is inherently a
key requirements driver for the ICF Program Framework. The ICF Program
mission drivers are derived from the SSP needs captured in the HED Science
Strategic Plan, particularly in the Thermonuclear section of that Plan. In
addition, the broader HED weapons science portfolio relies on the ICF
Program to produce HED environments through its world-class facilities andexperimental capabilities such as advanced target designs, diagnostics, andfacility operations.

2.2

Key Technical Focus Areas

The HED strategic plan consists of four key weapons physics areas aimed at
replacing empirical models with experimentally-validated models in weapons
codes: nuclear; TN; radiation transport; and outputs, environments, andeffects. The HED portfolio must support specific assessment capabilities that
increase the design options of life-extended weapons by replacing components
and materials, adjusting to changes in manufacturing processes, improving
safety and surety, and meeting vulnerability and hardness requirements.
Thermonuclear aspects of nuclear weapon performance are a focus of major
HED future efforts. This focus will require TN burn capabilities of varying
yields (100 kilojoules through multi-megajoules) that are being developed by
the ICF Program.
2.2.1

Nuclear

The nuclear HED area is advancing understanding of the implosion phase of
a nuclear weapon. Major physics topics in this area include hydrodynamics,
material properties under extreme conditions, and nuclear physics.
Hydrodynamics in the nuclear phase is complex and has a profound impact
on nuclear weapon performance. Stability of implosions and turbulence arefundamental to address, concerning the hydrodynamics in a plasma media.
Figure 2-2 shows data from a NIF experiment demonstrating a mixing
layer structure under HED conditions. Hydrodynamic evolution is strongly
dependent on material properties and external conditions, such as thepresence of strong magnetic fields. HED experiments provide precision dataon material properties at stockpile relevant conditions, such as TN (equationsof state (EOSs)), material phase, and strength.
2.2.2

Figure 2-2. A LANL experiment
depicting an interface that has been
shocked and sheared to study mix.

Figure 2-3. NIF ‘Bigfoot’ experiment.

Thermonuclear

Thermonuclear reactions reach very high temperatures and densities,
similar to those at the center of stars, supernovae, and nuclear weapons.
Validated models of the energy production from fusion reactions are needed
to understand weapon performance, including primary boost and secondary
performance. HED experiments at the three major ICF facilities cancontribute to understanding the interplay of TN physics and other physicalphenomena through the development of burning plasma platforms.
The primary mission of the ICF Program is to focus on developing a robust
TN burn platform and achieving multi-megajoule fusion yields (which require
ignition) and, ultimately, a high yield platform. The ICF Program is developing
a burning plasma platform using three approaches: LID (Figure 2-3 shows
an open shutter colorized NIF implosion inside the target chamber), LDD(Figure 2-4 shows a direct-drive cryogenic DT experiment on OMEGA), and
MDD (Figure 2-5 shows a Magnetized Liner Inertial Fusion (MagLIF) target,
implosion radiograph, and an x-ray image at stagnation).

National Nuclear Security Administration

Figure 2-4. An in-flight soft x-ray
radiograph of a low adiabat (a ~ 2.5)
cryogenic DT implosion on OMEGA
taken 200-300 ps before bangtime. The white dashed line is theoriginal capsule radius and the dark
circle (centered on x ~ 600 mm andy ~ 900 mm) is the in-flight DT shell.
9Figure 2-5. A MagLIF target.

Planned experiments on ignition and on applications of ignition include
a broad range of areas related to TN performance. Data from preciselydiagnosed burn experiments will help to elucidate the physics that must be
incorporated in sophisticated nuclear weapon simulation codes to assess andcertify options for the life extension programs of the Nation’s nuclear weapons.
These experiments will advance and validate physics models and numericalsimulation codes and will serve as integrated tests of simulation capabilities.
The conditions of ignition create very hot, dense radiative plasmas with highneutron flux. Burn and ignition physics experiments will address issues related
to TN reactions in deuterium (D) and tritium (T) as well as other nuclear
physics issues in a high neutron flux environment. This unique environment
will allow validation of physics-based models and numerical simulation codes;
assessment of weapon performance; and evaluation of output, environment,
and effects. Moreover, advances in the understanding of specific aspects of TNburn physics will inform the assessment of stockpile aging issues of current
interest and contribute to broader national security concerns.
2.2.3

Radiation Transport

Radiation transport research examines the propagation of x-rays and theirinteractions with materials. HED efforts measure radiation propagationin relevant geometries to validate the algorithms in weapon design codesand obtain data to validate opacity models that govern the absorption andtransmission of x-rays in nuclear devices. Figure 2-6 depicts a NIF target
used to study radiation transport. First-principles simulations of opacities
are beyond the scope of current supercomputers. Instead, opacity models
use approximate methods with uncertainties that are difficult to quantify inlarge-scale computer simulations. Experiments being conducted on Z and the
NIF are important for improving opacity theory and models, but are restricted
to lower temperatures and densities than those attained in nuclear weapon
explosions.
2.2.4
Figure 2-6. A typical NIF radiationtransport target.

2.3

Figure 2-7. Typical environments that
HED capabilities are used to simulate.
10Outputs, Environments, and Effects

Outputs, environments, and effects research (see Figure 2-7) focuses on
the post-explosion phase, in which the nuclear weapon releases x-rays,
neutrons, gammas, and blast waves that deliver a militarily effective responseto an intended target. Studying the physics of outputs and effects allows
an assessment of the intended and unintended consequences of weapon
explosion. This includes understanding the radiation output from U.S.
systems and adversaries’ systems, the response of U.S. systems to hostileenvironments generated by a nuclear-tipped interceptor or a fratricide
scenario, and extreme environments such as the electromagnetic pulses that
nuclear weapons may create. HED facilities contribute to understanding thesescenarios and to supporting the qualification of components of U.S. systems
to meet nuclear survivability requirements. Many investigations in this area
require new experimental and computational capabilities to explore theeffects of large neutron and x-ray outputs.

Summary

The capability to measure, model, and simulate conditions in the HED regime
is critical to the SSP. As stated by the Laboratory Directors in their letterto the NNSA Administrator, “Continued leadership in HED Science is andwill continue to be an essential component of a coordinated and balanced
sustainable national nuclear security enterprise.” The ICF Program vision isto deliver the HED science and capabilities to support the evolving nuclear
stockpile. The motivations for these efforts include stockpile changes observed
since the cessation of underground nuclear testing, weapon-performance
National ICF Program Framework The Ten-Year HED Science Strategic Plansensitivity studies, and uncertainty-quantification analyses. Aligned with theanticipated needs of future stockpile decisions, the resolution of nuclear and
TN uncertainties in the coming decade is the priority of HED research. This
will require the development of robust burning plasma platforms. NNSA
efforts to understand outputs and their interactions with the environment will
gradually increase. Efforts to understand radiation transport will gradually
lessen as key issues in this area are resolved.
In the absence of underground nuclear explosive testing, it is critical that the
NNSA have a means to sustain an expert workforce that can respond to boththe anticipated and unanticipated future needs of the Nation’s stockpile.
The ICF Program, in addition to the highly successful Stewardship Science
Academic Programs (see Developing the Next Generation: The Stewardship
Science Academic Programs on page 12 to learn more), has been effective
in recruiting and retaining the best and brightest future stewards, and inchallenging them with hard problems. Conducting HED experiments andachieving ignition in the laboratory, in particular, are extremely complex
and challenging problems. Weapons designers and experimentalists must
exercise the full range of modern SSP computational and experimental
capabilities to achieve these goals and demonstrate to allies and adversaries
that the U.S. nuclear deterrent remains safe, secure, and effective and that
we have the capabilities necessary to assess intelligence-based nuclear
threats when they arise.

National Nuclear Security Administration

The ICF Program has beeneffective in recruiting andretaining the best andbrightest future stewards, andin challenging them with hard
problems. Conducting HED
experiments and achieving
ignition in the laboratory,in particular, are extremelycomplex and challenging
problems.






11

Developing the Next Generation
Stewardship Science Academic ProgramsT  he Nation’s
nuclear weapons
stockpile is a vital
part of the national
security infrastructure.
Ensuring that thedeterrent is second tonone requires the best
science and technology,
especially in the
post-nuclear testingera. Having top-tierscientists and engineers
in areas critical tostockpile stewardship isthe only way to ensure
the delivery of the best
science and technology
possible. The NNSA
supports this effort
through the Office of
Research, Development,
Test, and Evaluation’s
Stewardship Science
Academic Programs(SSAP).

The first objective of the SSAP is to support and train doctoral and master’s
degree science and engineering students to serve as potential stewards ofthe stockpile. A second objective is to engage highly-skilled academic and
NNSA scientists in the development of new ideas and techniques applicableto stockpile stewardship. A third objective is to ensure a strong communityof technical experts throughout the country, external to the national security
laboratories, to provide peer review, scientific competition, and depth andbreadth in research fields essential to NNSA’s mission.
The ICF Program benefits substantially from the following SSAP elements.
 The Stewardship Science Academic Alliances (SSAA) Program funds
fundamental research and development through Centers of Excellence,research grants, and fellowships in dynamic materials properties,hydrodynamics, low energy nuclear science, radiochemistry, and highenergy density physics.
 The High Energy Density Laboratory Plasmas (HEDLP) Program is
jointly conducted by NNSA’s Office of Inertial Confinement Fusion
and DOE’s Office of Fusion Energy Sciences. HEDLP funds grants
to study plasma in laboratory experiments, where the stored energy
reaches approximately 100 gigajoules per cubic meter (i.e., at pressuresof approximately 1 megabar). Some areas of interest include HED
hydrodynamics, radiation-dominated hydrodynamics, material
properties, nonlinear optics of plasmas, laser plasma interactions, andwarm dense matter.
 The National Laser Users’ Facility (NLUF) Program provides facility
time on the Omega Laser Facility. Through this program, two of theworld’s premier lasers for high energy density research, OMEGA andOMEGA EP, are accessible to the academic and industrial community
to conduct basic research experiments in low- and high-energy density
physics and laser-matter interactions and to provide the experience fora cadre of highly-trained scientists to conduct state-of-the-art researchin these areas of science and technology.

NNSA Stewardship Science
Graduate Fellowship Class of2015. Left to right: Nathan Finney,
Columbia University; Christopher
Miller, Georgia Institute ofTechnology; Brooklyn Noble,
University of Utah; Amy Lovell,
Michigan State University; Leo
Kirsch, University of California(UC) Berkeley, and Alison
Saunders, UC Berkeley.

12

National ICF Program Framework Integrated Experimental Campaigns

3

The Integrated Experimental Campaigns (IECs) constitute a major bodyof work totaling nearly half of all ICF experiments conducted at the major
facilities. The IECs are an approach-specific set of implosion experiments
whose primary objective is to baseline the target performance, demonstratescaling, test new design features and capabilities, and evaluate new ICF target
concepts. Performance metrics are highly integrated quantities such as total
neutron yield, and most objectives and milestones of the IECs are multi-year.
The 2020 goal of each of the three approaches (LID, LDD, and MDD) is todetermine the credible physics scaling to multi-megajoule fusion yields using
existing facilities, with LID also determining the efficacy of NIF for achieving
ignition. Each section below contains a description of the major IECs and afive-year schedule to achieve the 2020 goal.
Table 3-1 depicts a summary of the major phases for each approach towardthe 2020 goal. Section 6 presents the peer-review process that will be used toensure that the body of work being executed will, in fact, achieve the 2020 goal.

The IECs are an approachspecific set of implosion
experiments whose primaryobjective is to baseline
the target performance,
demonstrate scaling, test
new design features andcapabilities, and evaluate new
ICF target concepts.






3.1

Laser Indirect Drive

3.1.1

Phases of the Laser Indirect Drive IECs

The major deliverables for the five-year IECs are motivated by performance
discrepancies between one-dimensional (1D) predictions of NIF implosion
performance and measured performance. Figure 3-1 depicts a comparison
between the two. Understanding and replicating near-1D performance on the
NIF as a function of laser energy is the principal motivation for the IECs.
The 2020 goal is to: 1) demonstrate the efficacy of the NIF for achieving
ignition and, if unable to do so, understand why, and 2) demonstrate theefficacy of physics scaling arguments for multi-megajoule fusion yield. During
each phase, focused physics experiments will be performed to complement
the IECs with the goal of understanding and providing data to develop andvalidate predictive models (see Section 4.1). The combination of integrated
and focused experiments, coupled with predictive models, will form the basis
for evaluating progress toward the 2020 goal.
3.1.1.1 Phase 1 (FY 2016-FY 2017)
The major focus of Phase 1 is to address two issues that appear to limit capsule
performance:

Table 3-1. Summary of the Three Approaches to Achieve the 2020 Goal.

14

National ICF Program Framework Integrated Experimental Campaigns

Figure 3-1. Project 1D performance
as a function of laser energy (blacksquares) and measured performanceof NIF implosions (blue squares).

 time-dependent drive asymmetry of hohlraums dominated by laserplasma instabilities (LPI), and capsule support membranes that introduce capsule shell rupturesduring the implosion.
Both effects prevent efficient energy transfer to the hot spot and degradeconfinement. The goal is to develop symmetrically-driven implosions, with
reduced impact from the capsule support membranes, for subsequent studies
of capsule physics and target scaling. During this period, low-density gas-filledhohlraums with low levels of LPI will be used to develop symmetrically-driven
capsules. In parallel, new capsule mounting schemes will be developed andtested in integrated implosions to reduce the impact on the implosion. This
goal is to provide a foundation for understanding stagnation in a nearly 1D
environment and for exploring hohlraum and capsule performance scaling
and cliffs as the targets are pushed in more stressing directions.
3.1.1.2 Phase 2 (FY 2017-FY 2018)
During Phase 2, the new target designs developed in Phase 1 will be used todetermine the target scaling and performance cliffs. Specific Phase 2 activities
will include: Gradually increase the capsule velocity by combining higher laser powerand energy with thinner capsules until a performance limit or cliff isreached. This limit may be caused by a combination of reaching NIF’s
power and energy limits, loss of drive symmetry, or loss of capsule
integrity due to hydrodynamic instabilities.
 Reduce the case-to-capsule ratio (CCR), which is the hohlraum radius
divided by the capsule radius, until symmetry control is lost.

The five-year IECs for LID will
be executed in three phases.
 Phase 1. Develop
hohlraums that can drive
capsules symmetricallyand improve capsulemounting.
 Phase 2. Use
symmetrically driven
implosions to investigate
performance scaling andcliffs.
 Phase 3. Introduce
advanced hohlraums
that exhibit improved
symmetry control.

 Change the physical scale of the target at fixed CCR.
 Conduct comparative studies of capsules with an outer layer (called an“ablator”) of CH (plastic), high density carbon (HDC), or beryllium (Be).
Phase 2 will establish the performance limits of NIF capsule implosions in
simple cylindrical hohlraums with low LPI and enable the down select of theablator capsule material.
3.1.1.3 Phase 3 (FY 2019-FY 2020)
The Phase 3 goal is to introduce more advanced hohlraums that exhibit
improved symmetry control. Possible designs include hohlraums with lowdensity foam liners coupled with alternative geometries. Low-density foam
liners in simple cylindrical hohlraums should substantially improve thesymmetry control. Other advantages could include longer laser pulses andsmaller CCRs. The studies in Phase 2 will be repeated for these improved
hohlraums, using the most promising designs.
National Nuclear Security Administration

15

3.1.2

Detailed 2016 Activities

The major goal of the 2016 IECs is to establish the operable parameter spaceand drive strategy for ignition-relevant implosions for low LPI hohlraums,
which have improved symmetry control.
Integrated experiments planned for FY 2016 are shown in Figure 3-2, whichspans both hohlraum and capsule stability risk while building on existingdata as much as possible. The goal is to identify the parameter space below
the notional dashed curve in which the hohlraum is well behaved and goodsymmetry control can be obtained as a starting point for follow-on studies.
The parameter space is the ratio of hohlraum diameter to capsule diameteror CCR, and laser pulse length that relates to capsule convergence ratio (CR)and therefore to the potential 1D target gain for each ablator. Hohlraum gas
fill, detailed pulse shape, and laser pointing add degrees of control for drive
symmetry.
The IECs planned for 2016 for LID are depicted schematically in Figure 3-2
and listed in Table 3-2 at the end of this section.

Figure 3-2. The LID integrated
experiments are exploring theparameter space of CCR and pulse
length to optimize performance.
Different ablators (e.g., plastic, highdensity carbon, and Be are used to
explore the parameter space.

Bigfoot

Figure 3-3. (Left) X-ray of a plastic
cryogenic NIF capsule containing asolid layer of DT fuel prior to a shot.
(Right) False color x-ray image of
the DT “hot spot” that forms after
a similar capsule was imploded on
NIF experiment N140520 which
produced 9.3 x 1015 neutrons. The
DT in the hot spot has a temperatureof approximately 50 million degrees(more than four times that at thecenter of the sun) and a density
estimated to be 50 g/cc (about 1/3
that at the center of the sun or
50 times that of liquid water). It isestimated that alpha particle selfheating amplified the neutron yieldby roughly a factor of two in thisexperiment.
16

Bigfoot is a campaign that will evaluate the use of a short laser pulse thatcauses a low convergence (low gain) compression of an HDC ablator target
in a hohlraum. It will also test a design that is different from that of theconventional hot spot design. Bigfoot aims to implode the HDC capsuleto a convergence ratio ~ 20, such that the entire DT payload forms a large(ρR ~ 0.5g/cm2), high-temperature hot spot. Bigfoot does this by imploding
the capsule at high velocity (> 400 km/s), but on a high adiabat for stability.
The design begins with a thin DT payload and three shocks deliberately
mistimed to put the DT payload on a high adiabat. This design has the added
advantage that the pulse is relatively short (~ 6 ns). Once the drive and thesymmetry have been adequately controlled and the implosion behavior isunderstood, the fuel adiabat can be decreased in subsequent implosions by
gradually thickening the cryogenic DT layer (see Figure 3-3 for a genericdescription of a layered NIF target), while leaving the pulse, and hence thehohlraum drive and symmetry, unchanged. The capsule performance canthen be studied as the convergence ratio is gradually increased. Eventually,
additional pulse shaping would be required to achieve even higher
convergence ratios and would naturally move towards the regular highconvergence, longer-pulse HDC design.

FY 2016 goal: Complete initial experiments in 0.8 scale, CCR ~ 3 hohlraums toprovide hohlraum drive and symmetry characteristics for short pulses. Evaluate
the efficacy of the Bigfoot design for ignition to provide a symmetric implosion
for stagnation physics studies.

National ICF Program Framework Integrated Experimental Campaigns

High Density Carbon (HDC)

This long-pulse companion (high gain end) of the Bigfoot design uses thesame hohlraum size and gas fill to continue to explore a standard, three-shock(α ~ 2), high-convergence design (~ 30) at a 0.8 radius scaling. Experimentswith a low-convergence (~ 20) gas-filled capsule have exhibited low LPI andgood symmetry control by laser pulse shaping techniques.

FY 2016 goal: Determine whether there is a path to a hohlraum that supports asymmetric, three-shock, low-adiabat HDC design in a hohlraum with CCR ~ 3.
Two-shockTwo-shock experiments have used a conservative design with a CH capsuleand a CCR ~ 4. Experiments in near-vacuum or low-fill hohlraums and gasfilled capsules with convergence ratios up to ~ 17 have exhibited low LPI
and very round implosions. Testing this apparently high-quality hohlraum
environment at higher convergence with a DT-layered capsule requires anew, thinner capsule with a different inner radius but the same outer radius
to preserve the pulse length, hohlraum drive, and symmetry. Surrogate
experiments will be needed to quantify aspects such as shock timing.

FY 2016 goal: Conduct initial surrogate experiments leading up to an
evaluation of initial symmetry and performance for a DT-layered capsule withconvergence ratio ~ 20-27.
CH Ablator with Intermediate Fill Hohlraum (IFH)

The goal of this effort is to test the hypothesis that time-dependent drive
asymmetry is a major factor limiting the performance of a high foot implosion
with a CH ablator. The CH intermediate-gas-fill hohlraum experiments
will also establish the hohlraum LPI, drive, and symmetry sensitivity to
the gas fill, pulse length, and foot pulse level within the same design. These
trends in sensitivity should be similar to other low-fill hohlraum designs
even if quantitatively different. Experiments will be performed with a larger(6.72-mm-diameter) hohlraum, beginning with intermediate gas fill (~ 0.6 g/cc) and using laser pulses that emulate the radiation temperature history of
the original high foot experiments with a CH ablator to isolate the hohlraum
physics. The capsule will remain the same size as in the high foot implosions,
resulting in a CCR ~ 3 compared to ~ 2.5 for the LPI-dominated, 1.6-mg/cc,
He-filled hohlraum used for the high foot experiments. The pulse lengths varyfrom ~ 10-15 ns for the IFH target design.

FY 2016 goal: Explore laser pulse shape and gas fill to guide design parameters(CCR, pulse shape, gas fill) for symmetric implosion in a low-LPI hohlraum.
Beryllium Ablator with Large Case-to-Capsule Ratio

A Be ablator is predicted to be more hydrodynamically stable than CH or
HDC; hence, Be could reduce the effects of fill tubes and capsule mounts or
improve symmetry by enabling a larger hohlraum CCR with a lower associateddrive temperature.

FY 2016 goal: Conduct initial experiments using Be capsules in CCR ~ 4
hohlraums with the gas fill, laser pointing, and pulse shape optimized for Be
capsules.
Wetted Foams

Wetted foams offer the attractive possibility of allowing variation in thecapsule convergence ratio over a wide range by adjusting the central DT vapor
density while leaving the laser pulse unchanged. The experiments will use
developments in other concepts to guide the shape of the laser pulses and thehohlraum design.

FY 2016 goal: Conduct initial experiments using wetted foam capsules.

National Nuclear Security Administration

17

Table 3-2. Six Integrated Experimental Designs That Will Be Examined to
Develop Operable Parameter Space and Drive Strategy for Ignition-Relevant
Implosions Using Low LPI Hohlraums with Improved Symmetry Control.
Key
Be - Beryllium
CCR - Case-to-case ratio
CR - Convergence ratio
HDC - High density carbon
IFH - Intermediate fill hohlraum
LPI - Laser-plasma instabilities
mm - Millimeters
MJ - Megajoulesns - Nanoseconds

Campaigns

CCR

Hohlraum
Diameter (mm)Pulse length
(ns)

CR

Energy(MJ)

Bigfoot

3.2

5.75

~6

~ 20

~1.2

HDC

3.2

5.75

~8

~ 30

~1.2

Two-shock

4.25

5.75

~8

~15

~1.0

IFH

3

6.72

~10 – 12.5

~30

~1.6

Be

4.2

6.72

~5.1 – 8.4~20 – 24

~ 1.0

*Wetted foam

3.2

5.75

~6

Variable~1.0*Originally planned to use the HDC platform, but may use the two-shock platform depending on
target fabrication.

3.2

Laser Direct Drive

3.2.1

Phases of the Laser Direct Drive IECs

The major deliverables for the five-year IECs are motivated by analysis of
OMEGA experimental data and two-dimensional (2D) and three-dimensional(3D) simulations that suggest inadequate laser power balance is the leading
cause of performance degradation for fuel adiabats (α) greater than about
3.5 as depicted in Figure 3-4. Similar analysis suggests that the performanceof low-adiabat implosions (α< 3) is further degraded by shorter wavelength
perturbations arising from the target quality at shot time (e.g., target surface
particulates and shell imperfections during fabrication) and laser imprint. The
combination of long and short wavelength perturbations leads to the break-up
of the compressed shell during deceleration and the mix of ablator material
into the hot spot. Understanding this behavior is the principal motivation for
the IECs.
The 2020 goal is to: 1) demonstrate an inferred hot spot pressure of
100 gigabars and, if unable to do so, understand why, 2) understand LPI
mitigation and control at the ignition length scale, and 3) demonstrate theefficacy of physics scaling arguments (such as hydrodynamic-equivalence) for
multi-megajoule fusion yield. During each phase, focused physics experiments
will be performed to compliment the IECs with the goal of understanding andproviding data to develop and validate predictive models (see Section 4.2). The
combination of integrated and focused experiments, coupled with predictivemodels, will form the basis for evaluating progress toward the 2020 goal.

Figure 3-4. Depiction of theGeneralized Lawson Parameterscaled to 1.8 MJ calculated for aseries of recent OMEGA implosions(the measured performance is shownby the blue diamonds) as a functionof the fuel adiabat with (the redboxes) and without CBET (the yellow
trend line).

Fuel adiabat

18

National ICF Program Framework Integrated Experimental Campaigns

3.2.1.1 Phase 1: Develop Capabilities for High Performance Implosions
on OMEGA
The major focus of Phase 1 is to improve the laser, target, and diagnostic
capabilities at OMEGA with the goal of conducting hydrodynamic-equivalent
implosions in Phase 4. Phase 1 will address the following concerns:
 Improve low-mode drive uniformity and implosion symmetry for highconvergence ratios;
 Establish predictive control of the fuel adiabat; Mitigate and control laser imprint; and Mitigate and control ablator surface and bulk features created during
fabrication (e.g., capsule mounting, tubes for fuel filling, target insertion
and alignment).
Some imprint control experiments will be done on the NIF, where beamsmoothing is limited.
Currently, laser power balance at OMEGA is insufficient for convergence
ratios > 17, where low- and mid-mode drive nonuniformities lead to shell
breakup near peak burn. Phase 1 will include an extended power balance IEC
to ensure that the drive uniformity and implosion symmetry are sufficient fora high convergence ratio implosion of ~ 22-25. In addition, Phase 1 OMEGA
experiments will perform with different ablators, target alignment, and drive
pulses designed to change the predicted growth rates.
3.2.1.2 Phase 2: Develop and Test Strategies to Mitigate and Control
Laser-Plasma Instabilities
The major focus of Phase 2 is to develop and validate LPI modeling, andidentify and test LPI mitigation schemes on OMEGA and the NIF. The
primary laser-plasma instability issues are: cross-beam energy transfer (CBET), two-plasmon decay (TPD), and stimulated Raman scattering (SRS).
Phase 2 will test three zooming schemes on OMEGA. In the first, the laser spot
profile under fills the target diameter at the start of the pulse, which mitigates
CBET at the expense of drive uniformity early in the implosion. The second
scheme is to fabricate a dedicated set of “zooming” phase plates such that the
inner part of the phase plate generates a larger spot size to match the target
diameter at time zero and the outer part generates a smaller spot to matchthe converged shell size later in the pulse. The third scheme, bandwidth as a
mitigation option for high-performance DT-layered implosions, can be testedon the NIF since each set of 48 quads can, in principle, propagate a different
wavelength.

The five-year IECs for LDD will
be executed in four phases,
with the first three runningconcurrently.
 Phase 1. Develop thecapabilities for highperformance implosions
on OMEGA.
 Phase 2. Develop and test
strategies to mitigate andcontrol LPI.
 Phase 3. Advance themodeling and test thelimits of 1D physics and3D predictions.
 Phase 4. Test the
integrated target
performance.

NIF experiments will determine if SRS makes significant contributions, since
SRS is energetically insignificant at the OMEGA scale. A TPD/SRS mitigation
campaign will be developed, with experiments on the NIF and OMEGA. Thisevaluation requires target fabrication development and the modification of
NIF optical diagnostics.
3.2.1.3 Phase 3: Advance Modeling and Test the Limits of 1D Physics
and 3D Predictions
The objectives of Phase 3 are to: Develop a comprehensive understanding of low convergence ratio (< 17)
direct-drive implosions, which are less susceptible to hydrodynamic
instabilities, andNational Nuclear Security Administration

19 Test the validity of 1D physics models and the hydrodynamic responsewith 3D models.
Implosions with a convergence ratio < 17 provide a limiting case of target
performance to test the understanding of LDD ICF physics. The strategy
is to perform high-adiabat (α > 7), low- convergence (~ 10) cryogenic DT
implosions and compare them to 1D simulations. The fuel adiabat will
be varied to observe when the implosions deviate from 1D behavior. The
dependence on laser power balance and target offset will be explored.
Characterized perturbations will be applied to the capsule and the results will
be compared with 1D and 3D predictions. Some of these experiments may bedone on the NIF as well as on OMEGA.
3.2.1.4 Phase 4: Test of Integrated Target Performance
The focus of Phase 4 will be to test the integrated target performance basedon the capabilities and knowledge developed during the other three phases.
The ultimate goal is to demonstrate LDD implosions with hot-spot pressuresof 100 Gbars. This will be accomplished through two integrated experimental
campaigns. The intent is to demonstrate near hydrodynamic-equivalent hotspot pressures consistent with predictions and to understand the “robustness”
to initial conditions and engineering features, or to understand why suchrobustness is not possible.
The goal of the first campaign is to achieve an inferred hot-spot pressure of
80 Gbars. This is the maximum pressure that current predictions suggest is
possible without CBET mitigation. New capability requirements developed
and tested in Phase 1 will be phased with the experimental schedule as therequired laser and target capabilities are attained. No major platform changes
are required for the 80 Gbar campaign (see Figure 3-5 depicting a canonicalDT implosion on OMEGA).
A new cryogenic target platform is likely required to meet the capsulesmoothness requirements of the second campaign, where the goal is todemonstrate a near-ignition, hydrodynamic-equivalent hot-spot pressure of
100 Gbars. This platform would use a fill tube rather than permeation to fill
the direct drive capsule with DT fuel. It is expected that CBET mitigation will
be required to achieve the 100 Gbars hot-spot pressure.
3.2.2

Detailed 2016 Activit﻿ies

The major IEC activities in 2016 are summarized below. Many of these IECs
will continue beyond 2016. The IECs planned for 2016 for LDD are listed inTable 3-3 at the end of this section.

Figure 3-5. A fast x-ray framing
camera is used to image the ablation
surface during a cryogenic DT
implosion (top). Implosion velocity is
inferred from the blue points at theend of the laser pulse (the laser pulse
is shown by the black trace in thebottom figure). The motion of the CDDT interface is shown by the green
points.

20

National ICF Program Framework Integrated Experimental Campaigns

Power Balance

The goal of this campaign in FY 2016-2018 is to test the sensitivity of layered
DT implosion performance to deterministic changes in the power balanceof the OMEGA laser. Current power balance is a factor of two to three times
worse than required for the hydrodynamic-equivalent performance campaigns
based on 3D simulations. The campaign will verify the role that power balance
plays in the final symmetry of the shell and hot spot during peak burn.
Primary diagnostics include in-flight and near stagnation imaging of the shelland stagnation imaging of the fuel hot spot.

FY 2016 goal: Identify and correct 1ω laser energy losses and energy
measurement accuracy gaps that could affect the final ultraviolet energy
delivered to target and update the Auto Balance algorithms used to determine
the optimum 1ω energy balance.
Shock Timing

The goal of this campaign is to verify the prediction of laser coupling andadiabat control in the fuel shell using the cryogenic cone-in-shell platform.
In particular, establish a predictive capability for the formation of the main
drive shock. Once the platform is established for the main drive shock, theseexperiments will be conducted routinely as part of the performance and 1D
campaigns to verify the pulse shape performance against prediction prior to
integrated layered DT implosions. The need to execute these experiments withlayered fuel will be assessed. The primary diagnostics include the Velocity
Interferometer System for Any Reflector (VISAR) and streaked opticalpyrometry.

FY 2016 goal: Verify that target alignment can be maintained at shot time andconduct a series of experiments with increasing main drive intensity.
Ablator

The initial goal of this ambient implosion campaign (non-cryogenic) is toestablish ablator options to address LPI control by tailoring the coronalplasma. These experiments will transition to the cryogenic platform once filltube capability is established. The initial experiments in this campaign were
performed in FY 2015. Tests using the polar direct drive (PDD) implosion
platform on the NIF are possible.

FY 2016 goal: Measure the hot electron production and mitigation when
applying techniques to reduce CBET in ambient gas-filled implosions.
Zooming

The goal of this campaign is to verify CBET mitigation strategies with
implosions on OMEGA. Initial layered DT implosions in FY 2015 showed that
reducing light over the capsule horizon by reducing the laser spot size relative
to the target diameter reduced CBET as predicted. This occurred, however,at the expense of laser drive uniformity early in the laser pulse. Zooming
options that potentially do not impact early time drive nonuniformity include
advanced phase plate designs (a prototype has already been fabricated) anddedicated optics that produce a wavelength-dependent spot profile.

FY 2016 goal: A series of imprint efficiency measurements will be taken toquantify the degree to which imprint increases when using a sub-aperture partof an OMEGA beam.
Wavelength Control

The goal of this campaign on the NIF is to establish that the proper use ofdifferent laser wavelengths on target can be used to mitigate CBET. The NIF
is uniquely capable of producing significant quad-dependent wavelengthvariations. Changing the wavelength of opposing beams changes the spatial
location and, consequently, the level of stimulated Brillouin scattering (SBS)
losses. These experiments will be based on the PDD implosion platform.
National Nuclear Security Administration

21

LLE is scoping options and costs for adding additional laser drivers to study
wavelength control using the OMEGA laser toward the end of the decade.
(CBET mitigation is necessary for the second hydrodynamic-equivalent
performance IEC.)

FY 2016 goal: Experimentally establish the baseline hydrodynamic
performance (no wavelength differences) for implosions using the PDD
platform on the NIF, where the beams are repointed so that the current NIF
wavelength capabilities can be tested with two different wavelengths aboveand below the equator.
1D Physics

The goal of this campaign is to test the physics models in the hydrodynamic
design codes using implosions that are hydrodynamically stable (e.g.,fuel adiabats > 7 and convergence ratios of 10) and in which the couplingenergetics is well characterized. With a robust 1D platform, parameter scans(adiabat, velocity, convergence) will be performed and the data will becompared with prediction to identify where in parameter space the models
need to be improved.

FY 2016 goal: Use four cryogenic DT implosion shot days in FY 2016 to perform
an adiabat scan from α~ 7 to α~ 3 using a two-shock, single picket pulse
shape. Perform an intensity scan (at least two main drive intensities) at each
adiabat while keeping the shock timing fixed.
3D Hydrodynamics

The goal of this campaign is to deliberately add 3D perturbations to thecryogenic DT capsule and/or to the laser drive to compare the measured
performance of the shell with 2D and 3D predictions. Examples of thedeliberate perturbations include the addition of a dummy stalk, low-mode
cryogenic DT and capsule distortions, and drive non-uniformities (by varying
the laser energy).

FY 2016 goal: Establish 3D direct-drive modeling and predictive capabilities
with the HYDRA code (Lawrence Livermore radiation hydrodynamics 		code) at LLNL and the new 3D ASTER code at LLE; no campaign-specificexperiments are planned in FY 2016.
Table 3-3. Summary of Laser Direct Drive Integrated Experimental Campaign
Activities.

Key
1D - One-dimensional
3D - Three-dimensional
CBET - Cross-beam energy
transfer
NIF - National Ignition Facility
LPI - Laser-plasma instabilities

22

Campaign

Facility

Goals

Platform

Power Balance

OMEGA

Improve low mode drive nonuniformity, Implosions
beam pointing and target alignment
stability

Shock Timing

OMEGA

Establish predictive adiabat control

Cone-in-shell

AblatorOMEGADemonstrate LPI control using ablator
materials to tailor coronal conditions

Implosions

Zooming

OMEGA

Test the concept and performance
limits for CBET mitigation

Implosions

Bandwidth Control

NIF, possibly
OMEGA

Test the use of wavelength variations
to control the SBS process leading to
CBET

Implosions

1D Physics

OMEGA

Test the limits of current models,facility capabilities and LPI
understanding

Implosions

3D Hydrodynamics

OMEGA,
possibly NIF

Test the predictive capability of the
3D hydrocodes against deliberate
low mode engineered and drive
perturbations

Implosions

National ICF Program Framework Integrated Experimental Campaigns

3.3

Magnetic Direct Drive

3.3.1

Phases of the Magnetic Direct Drive IECs

The major deliverables for the five-year IECs are motivated by calculations ofZ performance over a range of achievable peak currents. Figure 3-6 depicts
expected performance. Determining the scaling as a function of current of
performance and comparing that to calculations is the principal motivation for
the IECs.

Yield (MJ)

Figure 3-6. Projected performance asa function of peak Z current. The 80,
85, and 90 markers represent the Z
Marx charge voltage.

Peak Current (MA)The 2020 goal is to: 1) demonstrate 100 kJ DT equivalent yield and, if unable
to do so, understand why, and 2) demonstrate the efficacy of physics scalingarguments (i.e., with current) for multi-megajoule fusion yield. During
each phase, focused physics experiments will be performed to complement
the IECs with the goal of understanding and providing data to develop andvalidate predictive models (see Section 5.3). The combination of integrated
and focused experiments, coupled with predictive models, will form the basis
for evaluating progress toward the 2020 goal.
3.3.1.1 Phase 1 (FY 2016-FY 2018)
The primary focus of Phase 1 is to demonstrate the physics scaling andincrease the neutron yield by enhancing existing capabilities. Theseenhancements include: Deliver more laser preheat energy (from 4.5 kJ to > 6 kJ) to the fuel andco-inject a second laser beam to increase the pulse shaping capability; Integrate distributed phase plates in the Z-Beamlet laser to control spot
size, pulse shape, and penetration depth for laser energies up to 6 kJ
 Improve the load hardware to increase the current delivered to a target
from the present 17-18 MA to 22-24 MA;
 Increase the magnetic field coils in baseline MagLIF target designs from
17-20 Tesla to 30 Tesla; Implement methods to reduce the mix of liner material with the fueland ensure higher compressibility (e.g., electrically-insulated coatings
on the liner surface; low density, thick liners); and Test new or hybrid target concepts (e.g., MagLIF targets withalternative preheating mechanisms).
A second major Phase 1 focus is conducting the first Z tests with trace
amounts (0.1%) of tritium in the deuterium fuel. Even at small percentages,
tritium can enhance the scientific understanding and productivity on Z
through the use of tritium-related diagnostics developed by the LID and LDD
approaches. Processes for handling tritium on a pulsed power facility mustalso be developed and experience gained in order to credibly define the costs
for and operation of an ignition-class facility. The tritium tests are essential

National Nuclear Security Administration

The five-year IECs for MDD
will be executed in two phases
somewhat concurrently butwith distinct emphases.
 Phase 1. Complete initialcapability to conduct
MagLIF experiments
at 22 megaamperes(MA) on Z using a seedmagnetic field of 30 Tesla(i.e., 30 T) and laser
preheating capabilities
with energy of 6 kJ.
 Phase 2. Optimize ICF
target performance anddemonstrate neutron
yield scaling over theavailable conditions,with a goal of achieving
100 kJ DT equivalent. In
addition, demonstratemagnetization (BR) in
excess of 0.5 megagausscentimeters (MG-cm) anda pressure-time productof 5 Gbar-ns in MagLIF
targets.

23

to quantify the effectiveness of the containment and the distribution andpathways for tritium migration in Z. In 2017, the initial tests will be extended
to 1% tritium in a contained geometry and 0.1% tritium in an uncontained
geometry. Without significant new investment, tritium fills to 3%, but nolarger, may be possible.
3.3.1.2 Phase 2 (FY 2018 – FY 2020)
For FY 2018-FY 2020, the IECs for MDD will primarily focus on developing
optimized targets to demonstrate the scaling of neutron yield to validate
the extrapolations to ignition and high yield. Once the key capabilities (e.g.,increased laser energy, magnetic field strength, and peak current) have been
demonstrated during Phase 1, a number of Phase 2 experiments will explore
the different combinations of these variables and diagnose the results. Current
levels of 22-24 MA in Phase 2 may be possible by using a combination ofhigher charge voltages, lower inductance, and more optimal load hardware. At
24 MA, 2D LASNEX calculations predict that an optimized target design with
30 Tesla and > 6 kJ of preheat will produce > 100 kJ DT yield. The validity ofthese predictions would be the main deliverable of the IECs on Z. Figure 3-7
summarizes the typical measurements made on a MagLIF integrated
experiment.
The MDD activities in Phase 2 will include: Integrate tritium-containing targets (see discussion in Phase 1);
 Modify the final optics assembly on Z to allow simultaneous laser
heating of MagLIF targets and side-on radiography (presently only one
or the other can be done); and Improve laser preheating to deliver up to 10 kJ by increasing the optics
for the second, co-injected beamline to 40-cm diameter (the same as thefirst beamline).
Depending on the Phase 1 tests, it might be possible to achieve up to 50%
tritium fills by 2020 in a contained geometry while using only up to 3% fills

Figure 3-7. Integrated MagLIF
experiments produce a wealth of dataneeded to assess the overall target
performance and scaling.

24

National ICF Program Framework Integrated Experimental Campaigns

in an uncontained geometry; 50% tritium fills might subsequently be possiblein even uncontained geometries. System upgrades for > 3% tritium fills on Z
would be expected to include: Improve the purging and ventilating of the Z vacuum section;
 Improve the refurbishment tent (where Z hardware is processed after
each shot); Implement a heating, ventilating, and air conditioning capability for the
Z building; Improve the neutron shielding (2 x 1015 DT neutrons as the present
estimated limit);
 Develop a hardware set devoted specifically to tritium experiments; and Implement a tritium filling station as well as a tritium capture system.
Sufficient glass and front-end optics may be available from the original
Beamlet project to deliver up to 10 kJ. Increasing the laser energy to 10 kJ will
require additional experiments to develop the phase plates, laser pulse shapes,
and gas fill pressures for the higher energy. The additional preheat energy will
increase the likelihood of achieving 100 kJ DT-equivalent yields.
A second Phase 2 objective is to demonstrate some fundamental precepts ofmagneto-inertial fusion; this objective will require continued improvementof Z’s stagnation and burn diagnostics. Concepts such as MagLIF rely onstrong magnetic fields to reduce the traditional pressure, density, and ρR
requirements for fusion. For sufficiently high magnetization, typically
expressed by the parameter BR > 0.5 MG-cm, ignition would be possible
even in relatively low-density plasmas. When this condition is satisfied, thecharged alpha particles produced by the DT reactions are confined to helicalorbits with radii less than the cylindrical plasma radius R. Since the pressure
for fusion scales as the product of the density and temperature, reducing thefuel density and ρR by about 100 (e.g., see Figure 3-8) means the pressure
can likewise be reduced by a factor of 100. The key metrics for MagLIF
experiments on Z are the demonstration of BR > 0.5 MG-cm and a pressuretime product of 5 Gbar-ns.
3.3.2

Figure 3-8. Ignition space (dT/dt > 0)plots for magneto-inertial fusion. The
MagLIF concept seeks to demonstratefusion at roughly 100x lower densityand pressure than traditional ICF
through large magnetic fields (BR >0.5 MG-cm), which replace ρR as the
key metric.

Detailed FY 2016 Activities

The chart in Figure 3-9 illustrates the distribution of ICF shots on Z during
2016. (The Z schedule is defined by calendar year instead of fiscal year.)In keeping with the relative immaturity of the MDD approach, most Z
experiments are geared toward focused physics experiments, as defined by
the Priority Research Directions (see Section 4.3). Once PRD experiments for
MDD studies on OMEGA EP, the NIF, and Z-Beamlet are included (mainly for
Target Preconditioning studies), the overall PRD effort is roughly 85%, withthe remaining 10-15% devoted to the IECs and associated scaling studies.
Specific IEC activities on Z in FY 2016 for MDD are summarized in Table 3-4
and will include the following: Implement new phase plates for Z-Beamlet to improve laser-gas
coupling to leverage the understanding gained on OMEGA EP at LLE
and on the PECOS chamber at SNL; Conduct experiments with plastic-coated liners to determine the effecton the 3D stability of the MagLIF target designs;
 Use cryogenically-cooled gas to provide better laser-gas coupling as well
as a thick-ended liner to decrease the possibility of laser-induced mix
with the fuel; andKey
DTC - Driver Target Coupling
Precond. - Target Preconditioning
S & Burn - Stagnation and Burn

Figure 3-9. Distribution of ICF
program shots on Z in calendar year
2016. The 64 shots for ICF are split
between 47 shots for PRDs and 17
shots for IECs.

 Explore alternative magnetically-driven target concepts.
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25

Stag MagLIF 16a

This campaign uses understanding gained on OMEGA EP at LLE and the
PECOS chamber at SNL to explore improved laser-gas coupling by using newphase plates for Z-Beamlet.
Stag MagLIF 16b

This campaign leverages previous experiments on OMEGA EP at LLE andon the PECOS chamber at SNL. The goal is to achieve improved lasergas coupling using both new phase plates and new laser pulse shapes for
Z-Beamlet.
Stag MagLIF 16c

This campaign builds on multi-year implosion research on Z by integrating
plastic-coated liners into MagLIF designs to test improvements to the 3D
stability of the liner.
Cryo MagLIF

This campaign will integrate cryogenically-cooled gas MagLIF targets into
the Z implosion platforms, enabling a much thinner laser entrance window(and hence better laser-gas coupling). The liner design will also be changed
to a thick-ended liner to eliminate the need for “cushion” end caps and thus
decrease the possibility of laser-induced mix.
Alternative Concepts

Alternative target concept exploration.
Table 3-4. Summary of Magnetic Direct Drive Integrated Experimental
Campaign Activities.

Campaign

Gas Fill
Pressure

Gas Fill
Density

Laser
Laser
Phase Plate Energy

Stag MagLIF
16a

60 psi D2

0.7 mg/cc 0.7 mm

2 kJ

2

SNL, LLE,
ARPA-E

Stag MagLIF
16b

60 psi D2

0.7 mg/cc 0.7 mm(or 1.1 mm)

2 kJ/TBD

4

SNL, LLE,
ARPA-E

Stag MagLIF
16c

60 psi D2

0.7 mg/cc 0.7 mm(or 1.1 mm)

TBD

3

SNL

Cryo MagLIF

15 psi D2

0.7 mg/cc 0.7 mm
at 70 K

TBD

3

SNL

Harding(assorted)

-

-

-

5

SNL

-

No. Contributors

SNL and LLE at the University of Rochester received a joint two-year Advanced Research
Projects Agency-Energy (ARPA-E) Award for a project to explore improved laser-gas coupling for
the MagLIF concept. Experiments are being conducted on laser facilities at both SNL and LLE.

26

National ICF Program Framework The Priority Research Directions

4

The Priority Research
Directions define a common
taxonomy for fundamental
physics experiments to develop
and improve models that are
ultimately used to predictthe performance of highly
integrated experiments.


The challenge shared by all ICF approaches is the presence of fundamental
gaps in understanding the physics of HED environments, particularly as theenergy density increases. These gaps drive the use of approximations andempirical models to simulate the complex implosion performance of whatare, in reality, complex targets. Researchers are conducting fundamental
experiments to replace these approximations and empirical models withphysics-based models by incorporating new experimental data. The intent
is to improve the accuracy of predictions of target performance for the
Integrated Experimental Campaigns (IECs).
The Priority Research Directions (PRDs) define a common taxonomy for
fundamental physics experiments to develop and improve models that are
ultimately used to predict the performance of ICF experiments executed underthe IECs. There are six PRD categories: (1) Driver-Target Coupling, (2) Target
Preconditioning, (3) Implosions, (4) Stagnation and Burn, (5) Intrinsic andTransport Properties, and (6) Modeling, Approximations, and Validation.
The first four categories map to successive time steps occurring in an ICF
implosion, from the delivery of energy from the “driver” (i.e., the laser orpulsed power system) to the target and its implosion, to “stagnation” (thetime of peak radiation production) and burn. The fifth category reflects thequantities and look-up tables for the intrinsic material and radiation transport
properties through relevant media that are used by computer models tosimulate the specific HED environment.
Fundamental physics experiments conducted for the first five categories
account for a majority of the facility time set aside for ICF experiments at the
NIF, OMEGA, and Z supporting the PRDs. The sixth category refers to themodels, integrated simulation codes, and data-driven validation activities
that together comprise the “predictive capabilities” used to simulate theimplosions.
The PRDs provide opportunities for scientific collaboration among thelaboratories and academia. For example, a National Implosion Stagnation
Physics Working Group has recently been formed across the three NNSA
national security laboratories, LLE, NRL, and academia to develop new
hypotheses and recommend discriminating experiments to address the
Stagnation and Burn PRD (see page 49 for more information). The PRDs
themselves are the product of collaborations, as the inaugural set of the PRDs
were the result of the May 2012 Science of Fusion Ignition on NIF Workshop.
In FY 2016, representatives from across the ICF community will gather in
Santa Fe, New Mexico to update the current set of PRDs to reflect recent
progress and future plans.
The following sections describe the fundamental physics associated withthe three ICF approaches to ignition. Table 4-1 offers an overview of thefundamental physics associated with the three approaches. The remaining
tables in this section provide a technical breakdown of specific challenges
that are being actively addressed by the community. This includes a sampleof the diagnostics, platforms, and modeling tools being used to improve ourunderstanding of the fundamental physics.

The detailed PRDs are provided
in Table 4-2 on page 29.

28

4.1

Laser Indirect Drive

4.1.1

Driver-Target Coupling

Laser light is propagated into a hohlraum and subsequently converted to xrays, which are in turn transported to the target. Gas-filled hohlraums, whichhave been the “workhorse” hohlraums used for LID, are not predictablewith present simulation codes and are thought to be a significant source of
National ICF Program Framework The Priority Research Directions

Table 4-1. Fundamental Physics Associated with the Three Approaches.

Categories

Laser Indirect Drive

Laser Direct Drive

Magnetic Direct Drive

Driver-Target
Coupling• Laser propagation, LPI, and
CBET• Hot electron production andtransport• X-ray generation andtransport• Hohlraum conditions andhydrodynamics• Electron transport andmagnetic fields• Time-dependent x-ray drive
symmetry and control• Laser propagation, LPI, and
CBET• Hot electron production andtransport• Electron transport andmagnetic fields• Time-dependent drive
symmetry and control(i.e., polar direct drive andspherical direct drive)• Convolute physics• Current pulse shaping• Current delivery to smallradii• Symmetry of current
delivery• Optimal power delivery via
hardware design

TargetPreconditioning• Shock propagation and• Shock propagation andtimingtiming• Fuel preheating by electrons • Fuel preheating by electrons• Glint (i.e., laser light• X-ray generation andreflecting off the hohlraumtransport (preheat of mid-Z
well at early time andablators)
impinging directly on thecapsule• Laser fuel preheating (LPI
window dissembly)• Fuel precompression• Electrothermal instabilities• Early-time contamination• Cyrogenic fuel layer

Implosion• X-ray ablation and rocket
efficiency• Hydrodynamic instability
and mix• Role of initial conditions(e.g., roughness, oxidation)• Effects of fill tube and target
support structure• Implosion symmetry andcontrol• Radiative and electron
ablation, rocket efficiency• Hydrodynamic instability
and mix• Role of initial conditions(e.g., roughness, debris)• Effects of fill tube andmounts• Implosion symmetry andcontrol• Flux compression• Magneto-Raleigh-Taylor
instabilities• Dynamic mix• 3D fuel assembly• Mass flow loss
• Radiation losses• Symmetry

Stagnation andBurn• Power and energy balance,
hot spot formation, andproperties• Incomplete stagnation,
asymmetries, and 3D flow
• Deceleration hydrodynamic
instability and mix• Radiative cooling• Power and energy balance,
hot spot formation, andproperties• Incomplete stagnation,
asymmetries, and 3D flow
• Deceleration hydrodynamic
instability, and mix• Radiative cooling• Magnetized stagnation andburn• Charged particle stopping• Deceleration instabilities
and mix• Non-Maxwellian particle
distributions

Intrinsic andTransport
Properties• EOS in compression andrelease• LTE and non-LTE opacity• Transport coefficients• EOS in compression andrelease• LTE and non-LTE opacity in
mid-Z ablators• Transport coefficients• Anomalous cross-field heattransport• Strength and strain• Conductivities• EOSs• Opacity

Modeling,
Approximations,and Validation

Integrated within the other five PRDs

performance degradation due to time-dependent x-ray drive asymmetry andhot electron preheat. The large time-dependent asymmetry is a consequenceof CBET invoked to boost the power of the inner cone of laser beams to
overcome the poor propagation of those beams to the hohlraum wall. The
dominant energy loss for these hohlraums is SRS on the inner cone at a lower
limit of ~15% of the total laser energy delivered to the hohlraum. Hohlraums
with little or no gas fill may be used to reduce LPI and hot electron production.
Figure 4-1 shows an experimental platform used to diagnose plasma
conditions in the hohlraum. More advanced hohlraum geometries and designs
may help reduce these deleterious effects further.
National Nuclear Security Administration

Key
3D -Three-dimensional
CBET - Cross-beam energy
transfer
EOS - Equation of state
LPI - Laser-plasma instabilities
LTE - Local thermodynamic
equilibrium
Non-LTE - Non-local
thermodynamic equilibrium

Figure 4-1. The view through the laser
entrance hole of the target showing asmall dot on the capsule used to track
the x-ray emission of the capsule as it
ablates.
29

4.1.2

Target Preconditioning

Shock propagation, fuel preheating caused by hot electrons, and glint (thelaser light reflecting off the hohlraum wall at early time and impinging directlyon the capsule) all affect the compressibility of the target. Shock propagation
before the main pulse is believed to be more predictable compared to theshock(s) launched during the main pulse, where the rate of rise of x-ray driveand hot electron preheat have more impact. Hohlraum designs with very low
hot electron production may be used to determine the role of hot electrons onfuel preconditioning and to isolate x-ray drive effects during the rise to peaklaser power.
4.1.3

Implosion

Implosion hydrodynamics is divided into two areas.

Figure 4-2. A NIF capsule withreentrant cone for measuring
instability growth is shown on
the left. The capsule has small
sinusoidal perturbations etched on
the surface. The target is placed ina hohlraum and imploded. On theright is a radiograph of the capsulein flight showing the growth of theperturbations.

 The first is 1D phenomena related to the basic physics of capsule
implosion, including the pressure generated by x-ray ablation,subsequent shock propagation, material compression, and capsuledynamics.
 The second is 3D phenomena that degrade the “1D” performance by
causing deviation from sphericity, principally by Richtmeyer-Meshkov(shock driven), Rayleigh-Taylor (pressure driven) and Kelvin-Helmholtz(shear driven) instabilities and x-ray drive asymmetry. Figure 4-2
depicts a typical platform for measuring instability growth in HED
conditions.
Instability occurs at the ablation front (the outside surface of the capsule,shown in Figure 4-3, at the interface between the inner surface of the ablator
and the frozen DT fuel, and on the inside surface of the DT layer. These 3D
effects occur during both capsule acceleration and deceleration. Both 1D and 3D
phenomena are influenced by material properties (EOS and opacity) and by the
x-ray drive spectrum. Surface perturbations lead to ablation-front instability,
which may be somewhat mitigated with drive pulse shaping. Capsule mounting
and filling features can impact the quality of high-convergence implosions andlead to an asymmetric hot spot in the fuel and also the mixing of the capsuleablator material into the hot spot.
4.1.4

Stagnation and Burn

Ideally, the DT fuel converges to form a central hot spot throughhydrodynamic compression by a cooler, denser DT tamping shell that confines

Figure 4-3. A NIF fusion target
contains a polished capsule about
2 millimeters in diameter, filled withcryogenic (super-cooled) hydrogenfuel. NIF uses capsules with the outerlayer composed of plastic, diamond,or Be.

30

National ICF Program Framework The Priority Research Directions

Table 4-2. Laser Indirect Drive Performance Metrics and Analytic Tools.

Laser Indirect Drive

Metrics

Diagnostics, Platforms, and Modeling• Absorbed laser energy andx-ray drive• SRS – influences drive
symmetry, hot electron
production, and energy loss
• Drive symmetry – inferredfrom simulations of surrogate
diagnostic targets

Diagnostics• Full aperture backscatter diagnostic for SRS,
SBS
• Gated x-ray images for wall motion and
implosion shape• Spectrometers for spectrum, plasma
conditions
Platforms• ViewFactor for drive, laser spot intensity,
plasma conditions, wall motion, and Aububble imaging
Modeling• NLTE, thermal transport, LPI, kinetics• Shock velocity and timing –sets minimum fuel adiabat
and maximum achievable fuelareal density• Hot electron preheat –increases fuel adiabat
constraining areal density

Diagnostics• VISAR for shocks, preheat
Platforms• Keyhole, re-emit (beaming electrons)
Modeling• EOS, suprathermal electron transport• Ablation front instability andgrowth factors – susceptibility
to shell breakup and mix• Implosion symmetry –influences efficiency of energy
transfer to hot spot andresidual energy

Diagnostics• Gated x-ray imagers for shape and hydrogrowth• X-ray spectrometers for mix
Platforms• 2DConA tent, fill tube imaging, implosion
shape• HGR for instability growth
Modeling• High resolution hydrodynamics, radiationtransport• Yield, Tion, areal density, burnwidth, hot spot, and cold fuelsize and shape vs. simulated– agreement between
observation and best model• Inferred hot spot properties
and power balance

Diagnostics• Neutron, x-ray spectrometers for Tion, ρR Te,
mix• X-ray, neutron imagers for fuel shape, burnwidth
Platforms• Layered DT implosions
Modeling• Integrated 2D and 3D rad hydro with HYDRA/
ARES, synthetic diagnostic signatures

Driver-Target Coupling• Laser propagation, LPI, andCBET• Hohlraum conditions andhydrodynamics• Time-dependent x-ray driveand symmetry control

Target Preconditioning• Shock propagation andtiming• Fuel preheating (electrons)• Glint

Implosion• X-ray ablation and rocket
efficiency• Hydrodynamic instability andmix• Effects of fill tube and tentKey
2D - Two-dimensional
3D - Three-dimensional
CBET - Cross-beam energy
transfer
DT - Deuterium-tritium
EOS - Equation of state
HGR - Hydro Growth Rate
LTE - Local thermodynamic
equilibrium
NLTE - Non-local
thermodynamic
equilibrium
SBS - Stimulated Brillouinscattering
SRS - Stimulated Raman
scattering
VISAR - Velocity Interferometer
System for Any Reflector


Stagnation & Burn
• Power and energy balance,
hot spot formation, andproperties• Incomplete stagnation,
asymmetries, and 3D flow

Intrinsic and Transport Properties• EOS in compression andrelease• LTE and non-LTE opacity• Transport coefficients• Agreement with theory as
defined by impacts on major
physics drivers (symmetry,compression, hydrodynamic
instability, hot spot formation)

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Diagnostics• VISAR, x-ray backlighting and scattering,
spectroscopy
Platforms• Customized platforms to isolate physics ofinterest
Modeling• Assortment of specialized theory-specific
codes

31

the hot spot long enough for self-heating to bootstrap to ignition. Shellsymmetry, integrity, and hydrodynamic instability all affect the transfer ofenergy to and the formation of the hot spot. Figure 4-4 depicts an experimentshowing the symmetry of an imploding capsule. Self-heating from alphaparticle deposition increases hot spot temperature and pressure, whilethermal conduction and radiative loss serve to cool the hot spot. The stagnatedfuel down-scattered neutron ratio (a measure of the fuel areal density) is
typically ~ 25% below the simulation predictions, while temperatures are
somewhat higher than predicted for reasons that are not yet understood. The
latter comparison is complicated by the fact that ion temperatures are inferredfrom the width of the 14-MeV DT neutron spectral peak, which is affected byfuel motion.
4.1.5

t-BT (ns)t-BT (ns)Figure 4-4. A convergent ablator
experiment conducted on the NIF.
Two x-ray backlit snapshots of the
imploding capsule are captured ateach time (marked left and right).
The time sequence runs top left
through bottom right and is marked
by time to “bang time” (maximum
yield production). The central hot
spot can be seen to form late in time(bottom right). Horizontal “scars”
resulting from the capsule support
membranes can also be seen (topbottom of each image).

The detailed PRDs are provided
in Table 4-3 on page 34.

Intrinsic and Transport Properties

Equations of state and opacities of the target components—from partiallyionized, weakly coupled regimes to strongly coupled regimes withcompressions by factors of ~1,000—are important for modeling capsule
implosions. Other important properties include the non-local thermodynamic
local thermal equilibrium (non-LTE) physics of the laser-gold interaction; thenon-local, potentially-magnetized thermal transport in the hohlraum (which
affects plasma temperatures, densities, and x-ray production); the non-local,
potentially-magnetized thermal transport from the hot spot into the cold DT
fuel (which moderates the hot-spot temperature, mass, and areal density);
thermal transport in the warm dense matter regime at the interface between
the ablator and the DT fuel (which sets the Atwood number for instability);electron-ion equilibration in the hot spot; and alpha stopping in the hot spot
and the surrounding cold fuel.
4.1.6

Modeling, Approximations, and Validation

Integrated modeling incorporates the “best” physics models, validated byexperimentation where possible, into HYDRA (the principal simulation code),with the goal of providing a tool to understand target behavior, quantify gaps
to reaching ignition, and illuminate potential paths to close those gaps. Large
3D simulations of the implosion, together with data from focused physics
experiments, are instrumental in explaining the capsule performance. For
low-gas-filled hohlraums where LPI is small, effort is focused on improving
non-LTE modeling of gold (and the transition between LTE and non-LTE) as
well as non-local thermal transport modeling augmented by validation data.
For gas-filled hohlraums, self-consistent, in-line models of LPI and CBET
must be added. These additions are being pursued at a reduced rate with thechange in the program emphasis to low-density gas hohlraums.

4.2

Laser Direct Drive

4.2.1

Driver-Target Coupling

Direct coupling of laser light to a capsule has a unique set of challenges
centered principally on the control of beam-to-beam interactions (also known
as CBET), thermal transport, and LPI. CBET can reduce laser coupling, which
decreases the implosion hydrodynamic efficiency, the ablation pressure
and, consequently the stagnation hot-spot pressure. Thermal transport
affects hydrodynamic profiles that govern laser absorption and CBET.
The LPI for laser direct drive are similar to those for laser indirect drive.
Multiple overlapping beams lead to additional deleterious effects such as
TPD instabilities, the threshold and scaling for which have been observed
experimentally in relevant configurations.
4.2.2

Target Preconditioning

As the capsule begins to implode, the shocks in direct drive targets must be
accurately timed to ensure the correct fuel adiabat at the end of acceleration.
32

National ICF Program Framework The Priority Research Directions

The cone-in-shell platform used to measure shock coalescence in liquid
deuterium with few picosecond accuracy is shown in Figure 4-5 alongwith an example of the data from the primary diagnostic. Fuel preheating
caused by hot electrons can impact the adiabat by changing the propertiesof the compressed fuel during acceleration. Estimates based on OMEGA
experiments suggest that fuel preheating may account for a degradation incompression relative to predictions by up to 10%. To mitigate CBET, a numberof novel laser irradiation techniques are being explored. These include laser
spot sizes that are smaller than the target, zooming beam sizing, and detuning
the laser wavelength. Efforts are underway to assess the impact of theseapproaches on target preheat, imprint, and low-mode drive nonuniformity.
Work is also underway to validate the modeling of hot electron suppression byusing mid-Z layers in the ablator.
Figure 4-5. A cone-in-shell target(left) is used to measure the shockstrength and coalescence for drive
pulses used on OMEGA. The VISAR
diagnostic looks through the coneat the inner surface of the shell.
The VISAR data on the right shows
discontinuities in the fringe patterns
as the shocks catch up with theleading shock.

4.2.3

Implosion

Direct drive implosions are sensitive to surface debris that can initiate
instability growth on short-length scales and illumination power imbalancethat can initiate longer-wavelength mode growth. Short-length-scaleinstabilities limit the adiabat (i.e., compressibility) of the implosion
and weaken the shell integrity when coupled with Rayleigh-Taylor andRichtmeyer-Meshkov instabilities, resulting in the mix of cold fuel and ablator
material into the hot spot. Long-wavelength modes lead to an asymmetric hot
spot, increased hot-spot volume, and reduced inferred pressure. Capsules may
be coated with this layer to reduce laser imprint.
4.2.4

Stagnation and Burn

Deuterium-tritium fuel assembly in LDD is determined by hot spot andstagnating shell symmetry, hot-spot internal energy, and RKE, and anomalous
thermal conduction (from magnetic fields). Figure 4-6 depicts the x-ray imageof an imploding direct drive target on OMEGA. A larger hot-spot volume thansimulated is mainly associated with early stagnation caused by ablation-front
hydrodynamic instabilities and fuel-hot-spot mix. Target performance islimited by core asymmetry that leads to larger hot-spot volumes and reducedpressures. Asymmetry in the shell areal densities amplifies RKE, reducing
the hot-spot internal energy and pressure. Experiments to address these

Figure 4-6. A sequential series of
x-ray core images of an imploding
direct drive cryogenic target
on OMEGA. The bang time is2.78 nanoseconds.

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33

Table 4-3. Laser Indirect Drive Performance Metrics and Analytic Tools.

Laser Indirect Drive

Metrics

Diagnostics, Platforms, and Modeling• CBET – coupling losses
reduce the ablation pressure
requiring mitigation strategies• Mass ablation rate –determines ablator hydroefficiency and validates
coupling models

Diagnostics• Optical Thomson scattering• Full aperture backscatter diagnostic for SRS,
SBS
Platforms• Mid-Z doped & layered ablators• Ablation surface and shell trajectories
Modeling• Improved CBET modeling based on firstprinciple calculations (LLE and LLNL)• Shock velocity and timing –sets minimum fuel adiabat
and maximum possible fuelρR
• Imprint–high spatial frequency
seeds for RT instability growthat the ablation surface

Diagnostics• 660nm VISAR laser plus optics• Streaked Optical Pyrometry• X-ray streak cameras
Platforms• Through-shell cone-in-shell radiography
Modeling• Improved 2ωp modeling using LPSE
developed at LLE)

Driver-Target Coupling• Laser propagation, LPI, andCBET• Electron transport andmagnetic fields• Time-dependent drive
symmetry and control

Target PreconditioningKey
2D - Two-dimensional
3D - Three-dimensional
CBET - Cross-beam energy
transfer
DT - Deuterium-tritium
EOS - Equation of state
LLE - Laboratory for Laser
Energetics (University ofRochester)
LLNL - Lawrence Livermore
National Laboratory
LPSE - Laser plasma simulation
environment
LTE - Local thermodynamic
equilibrium
NLTE - Non-local
thermodynamic
equilibriumnTOF - Neutron time of flight
RKE - Residual kinetic energy
SBS - Stimulated Brillouinscattering
SRS - Stimulated Raman
scattering
VISAR - Velocity Interferometer
System for Any Reflector
• Shock propagation andtiming• Fuel preheating (electrons)• X-ray generation andtransport (preheat for mid-Z
ablators)

Implosion• Radiative and electron• Implosion symmetry – few
ablation, rocket efficiency
percent-level laser power
imbalance influences shell• Effects of fill tube and mounts
uniformity at stagnation and• Implosion symmetry andresidual kinetic energy
control• Ablation front instability –susceptibility to shell breakup
and hot-spot mix

Diagnostics• Aspheric Crystal Imaging (soft x-ray
backlighting)• Streaked x-ray continuum
Platforms• Layered DT targets using fill-tubes• In-flight shell radiography w/soft x-ray
backlighting
Modeling• First-principles EOS modeling for relevant
ablators and hydrogen

Stagnation & Burn
• Power and energy balance,
hot spot formation, andproperties• Incomplete stagnation,
asymmetries, and 3D flow

• 1.9 MJ hydrodynamicsequivalent yield – expectationof SDD performance at 1.9 MJ• Hot-spot shape and radius– stagnation symmetry,
convergence, and hot-spotpressure• RKE–energy that does notheat the fuelDiagnostics• 3D nTOF• Neutron Temporal Diagnostic• Streaked x-ray continuum (Te)Platforms• 1D - lower convergence designs• Spherical strong shock
Modeling• Direct-drive 3D modeling (Aster)

Intrinsic and Transport Properties• EOSs in compression andrelease• LTE and non-LTE opacity in
mid-Z ablators• Transport coefficients

34• Fuel/shell compressibility,
conductivity, and opacity –first principles modeling• Hot spot mass – ablation fromthe inner ice surface• High Z opacity – assess use
for imprint mitigation

Diagnostics• Framing and streak cameras, VISAR,
spectroscopy
Platforms• Side-on radiography, impedance matching,
implosions, transmission
Modeling• First-principles EOS for relevant ablators andhydrogen

National ICF Program Framework The Priority Research Directions

limitations are planned. The effect of smaller beams that introduce larger,
low-mode asymmetry will be assessed. An assessment will be performed on
the NIF to study CBET mitigation of low-mode asymmetry by wavelength
separation.
4.2.5

Intrinsic and Transport Properties

Cryogenic direct drive implosions reach a strongly coupled and degenerate
plasma regime where the static, transport, and optical properties of warm
dense plasmas are not well known. Currently, quantum molecular dynamics
and Path-Integral Monte-Carlo methods are used to establish first-principles
EOSs, thermal conductivity, and first-principles opacity values of DT over awide range of densities and temperatures relevant for low-adiabat implosions.
These properties determine the shell compressibility, the optical propertiesof compressed material, the final shell densities, and stagnation pressures aswell as the amount of radiation heating from the plasma corona—all of which
influence the implosion performance.
4.2.6

Modeling, Approximations, and Validation

LDD modeling uses the 2D DRACO code and the 3D HYDRA code tounderstand the physics of the implosion. Important physics in thesesimulations are laser deposition via CBET and nonlinear heat conduction
as well as the effect of preheat from TPD and possible SRS on the adiabat.
The DRACO physics models have been verified with the 1D LILAC codefor spherical drive. LLE and LLNL are implementing noise-free ray trace
and CBET into the HYDRA code. Validation of the DRACO code for a PDD
geometry with OMEGA and NIF experiments is ongoing. Hybrid LPI andhydrodynamic simulations have been developed with limited success.
There are ongoing challenges to this LDD PRD. Code validation with NIF
experiments is challenging because of the significant non-uniformity in laser
illumination due to inadequate single-beam smoothing and LID distributed
phase plates not optimized for LDD. Multiple large-scale simulations in 2Dwith CBET and imprint and in 3D OMEGA cryogenic simulations exceed
LLE’s present computing resources. In addition, the integration of LPI
models in radiation-hydrodynamics codes leads to unrealistically long run
times. Therefore, a comprehensive LPI simulation toolkit, i.e., Laser Plasma
Simulation Environment (LPSE), is under development to provide guidanceon the development of more computationally friendly LPI models for thehydrocodes. NRL is also working with LPSE to develop LPI modeling options
for their FAST code.
Plans are being made to address these concerns by continuing 3D codedevelopment on HYDRA, wavelength detuning experiments on the NIF to
study CBET mitigation based on DRACO predictions, 3D simulations of all
OMEGA cryogenic and NIF PDD experiments, smoothing by multi-frequency
modulation, and NIF TPD experiments to understand TPD sources andtransport to improve DRACO models.

4.3

Magnetic Direct Drive

4.3.1

Driver-Target Coupling

Pulsed power machines store and discharge electrical energy, compressingthat energy in space and time. In the final stages of the compression, complex
arrangements of conductors combine into a single anode-cathode gap justbefore reaching the target. The electrical current pulse amplitude and timing
can be varied to tailor the drive conditions at the target (“pulse shaping”).
The pulse shaping is critical to avoid undesirable current loss and/or voltage
asymmetry. Within the target, plasma instabilities can affect the delivery

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The detailed PRDs are provided
in Table 4-4 on page 37.

35

of the current to small radii, placing effective limits on the peak magnetic
pressure that is achievable.
4.3.2

Target Preconditioning

The target implosion increases the plasma density and raises the plasma
temperature to the conditions needed for fusion. For some MDD designs (suchas MagLIF), strong magnetic fields are used to inhibit thermal conduction
losses. In addition, a laser is used to preheat the fuel prior to the implosion.
This enables more stable liners to compress the fuel. Figure 4-7 depicts theemission due to laser heating on a MagLIF development experiment. Methods
for heating the fuel can introduce contamination, leading to increased
radiation loss during the implosion. Prior to becoming a plasma, the flow ofcurrent in the metal liner volume can create instabilities, which can then seed
the magneto-Rayleigh-Taylor instability during the implosion stage.

Figure 4-7. Emission from fuel due toheating of the preheat laser.

4.3.3

Implosion

Magnetic pressure can be used to compress liner targets containing fusion
fuel, with the drive and acceleration increasing during the implosion as
the magnetic field strength increases. The dominant instability during the
implosion phase is the magneto-Rayleigh-Taylor instability. This can create
significant asymmetry and 3D structure. Figure 4-8 shows evidence of earlytime instabilities. The natural implosion geometry is cylindrical, hence thefuel within can be lost out of the ends during long implosion times. The long
implosion time of magnetized and preheated implosions means that radiation
losses have significantly more time to occur. The compression of magnetic
flux by the plasma liner is good, but not perfect, and the models have not beenvalidated at these plasma densities.
4.3.4

Figure 4-8. Radiograph of a MagLIF
implosion.

36

Stagnation and Burn

As the fuel plasma pressure increases, it eventually becomes comparable
to the magnetic drive pressure, and the liner and fuel begin to decelerate,
leading in turn to a variety of potential deceleration instabilities (RayleighTaylor, Kelvin-Helmholtz, etc.). The compressed magnetic flux in the fuel istypically chosen so that the charged particles produced in fusion reactions(tritons, alpha particles) are strongly magnetized with Larmor radii less thanor equal to the plasma radius. This can enhance the trapping of charged
particles in the fuel, depending on the plasma and field geometry. In manyz-pinch plasmas, there is ample evidence that a large fraction of the highenergy ions never fully thermalize, leading to non-Maxwellian particle velocity
distributions at the highest particle velocities that are largely responsible
for the fusion reactions. Self-emission from a MagLIF target at stagnation isdepicted in Figure 4-9.

National ICF Program Framework The Priority Research Directions

Table 4-4. Magnetic Direct Drive Performance Metrics and Analytic Tools.

Magnetic Direct Drive

Metrics

Diagnostics, Platforms, and Modeling• Optimizing implosion time –increased implosion time canreduce losses (lower dI/dt)• Pulse shaping – Possible toincrease implosion stability by
maintaining material strength

Diagnostics• Load current B-dot probes
Platforms• Mykonos: Pulsed power facility that can beused for scaled power-flow experiments
under conditions similar to those on futurefacilities
Modeling• Explore hybrid particle-in-cell models forplasma losses in power-flow regions• LPI – limit the coupling oflaser energy into the fuelbefore compression in
MagLIF, which increases
the velocity & convergencerequirements

Diagnostics• Spherical crystal x-ray imaging (backlighting
or self-emission)• X-ray spectroscopy (temperature, mix)
Platforms• Scaled-down MagLIF experiments on
OMEGA (ARPA-E funded)
Modeling• Improved conductivity, EOS for new liner
materials

Driver-Target Coupling• Power delivery and hardware
optimization• Current pulse shaping• Current delivery to small radii• Symmetry of current delivery

Target Preconditioning• Laser fuel heating (LPI,
window disassembly)• Fuel pre-compression• Electro-thermal instabilities• Early-time contamination• Cryogenic fuel layer

Implosion• Flux compression• MRT instability – The
dominant instability during the• Acceleration and deceleration
acceleration stage
instabilities• Flux compression – achieving• Dynamic mix
high magnetization at• Mass flow loss
stagnation requires• Radiation losses
compressing initial magnetic• Symmetry
field (affected by “Nernst”
losses)Diagnostics• Optical Faraday rotation fibers (magnetic flux
compression)
Platforms• Dedicated acceleration and deceleration
instability studies on Z
Modeling• Validate and improve magneto-hydrodynamic
models in multiple codes, including higherorder approximations (e.g., Nernst)

Key
ARPA-E - Advanced Research
Projects Agency-Energy
B - Magnetic field
BR - Magnetization
DFT - Density Functional Theory
EOS - Equation of state
LPI - Laser plasma instabilities
MRT - Magneto Raleigh-Taylor
instability
Li - Lithium
LTE - Non-local
thermodynamic equilibrium
MJ - MegajoulenTOF - Neutron time of flight

Stagnation & Burn
• Magnetized stagnation andburn• Charged particle stopping• Deceleration instabilities andmix• BR product – Representativeof how magnetized electrons
and fusion products are atstagnation; replaces areal
density (rho-R) as the key
criteria in magnetized targets• Fuel shape – Deformed
cylindrical assembly will lose
benefit of ρZ and increase
lossesDiagnostics• Neutron spectrometers for Tion, BR, yield,
particle distributions• X-ray, neutron imagers for fuel shapevisualization
Platforms• Tritium capability development experiments
on Z
Modeling• Explore hybrid particle-in-cell models
for current losses in high-convergence
implosions, as well as non-Maxwellian
particle distributions

Intrinsic and Transport Properties• Anomalous cross-field heattransport• Strength, strain• Conductivities• EOSs• Opacity• Liner and shell compressibility,
conductivity, and opacity(affects inertial confinement)• Fuel temperature andmagnetization during
implosion (as indicator of heattransport)

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Diagnostics• Spherical crystal x-ray imaging (liner
dynamics)• Optical emission/spectroscopy (fueltemperature)
Platforms• Implosion experiments to measure Te, B
versus time
Modeling• First principles DTF calculations of Li EOS

37

Figure 4-9. Self-emission x-ray imageof the high-temperature plasma
from MagLIF at stagnation (left),x-ray emission spectra from hot liner
material mixed into the fusion fuel(right).

4.3.5

Intrinsic and Transport Properties

Accurate electrical conductivity models are important for modeling thepreconditioning and implosion phases of the metal and plasma liners. In somecases, the current pulse shape can be tuned to leave a portion of the liner
volume in a near-solid state for a significant fraction of the implosion, making
strength, strain, and EOSs important. Models for the inhibition of electrontransport in magnetized system are known to have anomalies that require
corrections (Braginskii models). These have not been validated in most of theplasma density and temperature ranges of interest. Material opacities play alimited role in the success of typical magnetically-driven target approaches
but are extremely important for the analysis of data from these plasmas.
4.3.6

Modeling, Approximations, and Validation

Magnetically-driven target implosions are modeled similarly to laser-driven
systems, provided that the electromagnetic forces are added to the simulation
tools. A key problem is that liner implosions typically involve plasmas thatare both too low in density for fluid-based approximations to be truly valid,
and too high in density to allow the motion of particles to be directly modeledby particle-in-cell methods. Fluid-based approximations can often miss the
key physics, and extending particle-in-cell calculations to higher densities
requires the use of hybrid approximations that need to be better understood.
Laser-heating and LPI are extremely difficult to model. Two-dimensional
simulations are particularly prone to error, since the liner dynamics aredemonstrably 3D in nature when magnetized.

38

National ICF Program Framework National Diagnostics Plan

5

Recognizing the need forenhanced coordination
to develop advanced ICF
diagnostics, the ICF/HED
community formed the
National Diagnostics Working
Group of technical experts in2009.

Recognizing the need for enhanced coordination to develop advanced ICF
diagnostics, the ICF/HED community formed the National Diagnostics
Working Group (NDWG) of technical experts in 2009. Seventeen institutions
participate in the NDWG, including LLNL, LANL, SNL, LLE, GA, NRL, andMIT, and other organizations such as Princeton Plasma Physics Laboratory
and industry. International involvement from the Atomic Weapons
Establishment of the United Kingdom and Commissariat à l'Energie
Atomique et aux énergies alternatives (CEA) of France also contributes to thedepth and breadth of the NDWG. The group has focused on the development
and fielding of diagnostics to support national missions for NNSA’s ICF/HED
experimental facilities, in particular, NIF, Z, and OMEGA, and OMEGA EP.
The NDWG developed a National Diagnostics Plan (NDP) through multiple
workshops and focused technical meetings. The NDP is updated annually andregularly reviewed by an external panel of subject matter experts.

The scope of diagnostics
considered in the NDP ischaracterized as: Transformational: Major
national efforts with thepotential to transform
experimental capability
for the most criticalscience needs across thecomplex.
 Broad: Significant
national efforts thatwill enable new or more
precise measurements
across the complex.
 Local: Importantefforts involving theimplementation of
known technology for aparticular facility need.

The NDWG identified eight transformational diagnostics in the NDP, as
shown in Table 5-1. These will provide unprecedented information on
the implosion physics in fusion-relevant regimes, determine the plasma
conditions created by both laser and pulsed power drivers, and enable
dynamic measurements over a range of relevant conditions on the propertiesof materials utilized in nuclear weapons. The data provided by these
diagnostics will validate and improve the physics contained within the multidimensional simulation codes, and will uncover and quantify importantphenomena that lie beyond our present understanding.

5.1

Transformational Diagnostics

During 2015, the NDWG found a number of innovations for more optimal
technological solutions that improved performance, decreased cost, andaccelerated deployment. Examples of these innovations are: Use of a simpler recording technology for neutron imaging would
accelerate the scheduled implementation of polar imaging of
unscattered neutrons by more than 2 years with a decrease in cost of $5
million.
 The potential of GaAs diodes for 15-40 keV x-ray detection on hCMOS
cameras would accelerate the schedule for high-energy, single line ofsight (SLOS) detection by 1 year.
 Use of an existing NIF Preamplifier Module at LLE for the front end of
the NIF Optical Thomson Scattering (OTS) laser would accelerate theschedule by 6 months.

Table 5-1. Summary of the First Eight Transformational Diagnostics Formulated by the NDWG.

40

National ICF Program Framework National Diagnostics Plan Testing the first “single line of sight” on OMEGA during Q1 FY17 would
accelerate the schedule by about 6 months.
Technical Readiness Level and Schedule for Transformational
Diagnostics
Each of the transformational diagnostics includes multiple phases, realizing
both near-term and longer-term implementation of capabilities on thefacilities with increasing precision. Table 5-2 shows the estimated Technical
Readiness Level (TRL) of the least mature phase. One of the goals of the
NDP is to provide the impetus to bring each of these projects to a TRL of
9. Table 5-2 also shows the expected completion date of the entire project.
Portions of each project will be deployed much earlier than the date listed.
Hybrid CMOS. A SLOS detector (see Figure 5-1) will provide multi-frame,
high-time-resolution measurements of optical or x-ray signals with about
one million pixels. For images requiring ~ 10 ps time resolution, the fast
signal can be stretched by a “pulse dilation tube” to match the severalnanosecond gate time of this detector. This technology would replace microchannel plate (MCP) detectors that have been the standard for more than 20
years in this and many other applications. This capability will overcome many
MCP limitations by providing high dynamic range, flexible and shorter gatetimes, the ability to absolutely calibrate the detector system, and the ability
to record many time-gated images along a SLOS. This is a general technologythat will transform capability for all missions on the large HED sciencefacilities through improved precision and resolution in x-ray imaging andspectroscopy.
Optical Thomson Scattering (OTS). OTS irradiates a small plasma region with aprobe laser and uses broadening of the scatted light to measure electron and ion
temperature and density and collective behavior. OTS has been implemented
for many years on Nova, Trident, the Jupiter Laser Facility, and OMEGA, andTable 5-2. Minimum Technical Readiness Level and Expected Completion Dateof Each Transformational Diagnostic.

Diagnostic

TRL Today

Est. Completion

CMOS/SLOS

4

2020

OTS

6

2018

NIS

6

2020

GCD

3

2019

MRS-t

3

2019

HIRES

6

2019

Wolter5

2019

Diffraction

4

2020

Figure 5-1. (Top) Layout of the SLOS

imager. Projections of what theSLOS would image are provided atbottom left. A reconstruction using
those three projections is given atbottom right. Three orthogonal LOS
can theoretically provide some 3D
information. Modeling Analysis: N.
Izumi.

National Nuclear Security Administration41

it has demonstrated its fundamental feasibility for HED applications. The
transformational concept adopted by the NDWG is to use a deep ultraviolet
laser to allow scattering in a spectral region where the background from the NIF
or OMEGA laser beams and their harmonics are not overwhelming. A major
challenge is developing a drive laser compatible with the NIF architecture.
Potential applications are characterizing hohlraum plasmas and evolution for
LID, laser entrance window interaction and gas heating for MDD, underdense
plasma characterization for LDD, and electron transport and plasma
characterization for intrinsic and transport properties studies.
3D Neutron/Gamma Imaging (NIS). The NIS (see Figure 5-2) will
provide three views to capture neutron images in order to measure the fueldistribution at stagnation, the time at which neutrons are generated, and thetime when 3D structure is affecting nuclear performance. This diagnostic
allows tomographic reconstruction of the hot spot and cold fuel distributions
for comparisons to 3D simulations. A measure of this fuel structure is also
important in interpreting the data from the suite of nuclear data that iscollected on each experiment. Measurement of the fuel distribution allows
consideration of the effect on the other diagnostics as well as isolation andmeasurement of other processes that degrade nuclear performance.

Figure 5-2. Drawing showing the near
polar NIS on the NIS target chamber.
The near polar NIS will provide anearly orthogonal view to the present
equatorial NIS. It is being designed tobe compatible with the present polar
x-ray imager.

Figure 5-3. High-Resolution X-ray
Spectrometer for MagLIF.

Gamma Spectroscopy (GCD). The GCD provides improved time resolution
in reaction history and ablator areal density measurements for comparison
to predicted signatures of alpha heating and mix seen in recent simulations.
This necessitates diagnostic capability improvements in both sensitivity andtemporal response relative to the existing Gamma Reaction History diagnostic(GRH-6m) located 6 meters from the target chamber center. With improved
time resolution, the GCD could potentially study hot spot formation and burnpropagation, ablator and hot spot mixing, capsule areal density evolution, andion-electron equilibration, as well as nuclear astrophysics phenomena.
Time Resolved Neutron Spectrometer (MRS-t). Magnetic Recoil Spectrometry
with time dependence (MRS-t) enables time-resolved measurements ofthe fusion neutron spectrum. This diagnostic provides a time history of the
trajectory of areal density and ion burn temperature (ρR-Ti) that is importantfor diagnosing the performance of capsules at or near ignition conditions.
The MRS-t diagnostic is developed by MIT (see University Partnerships:
Massachusetts Institute of Technology on page 43 for a description of thatpartnership).
High Resolution X-ray Spectrometer (HiRes). High resolution spectroscopy(with a resolving power ~ 5000) on HED facilities will enable newexperiments in many areas of HED physics and warm dense matter (seeFigure 5-3). For instance, experiments on OMEGA have employed x-ray
absorption fine structure to measure the temperature of cold, compressediron. This technique will be extended to Z and the NIF. Presently, the densityof the hot spot of NIF implosions is inferred indirectly from measurementsof the neutron yield, ion temperature, neutron time of flight (nToF), andthe size and duration of implosions. Better constraints on the models
used in predictive simulations will require direct density and temperature
measurements through line-ratio, Doppler-broadened, and Stark-broadenedmeasurements of dopants in the hot spot enabled by high-resolution
spectrometers.
Hard X-ray Imaging (Wolter). Advanced x-ray optics developed mainly forspace applications, such as the Wolter microscope, will improve signal to noise
ratios, improve spatial resolution, and provide energy resolution for x-ray
imaging at photon energies > 15 keV. This diagnostic is needed for detailed

42

National ICF Program Framework National Diagnostics Plan

University
Partnerships

Massachusetts Institute of Technology

Massachusetts Institute of Technology (MIT). NNSA’s Dr. Keith LeChien and LLNL’s Dr. John Edwards met withstudents and scientific staff of the MIT HEDP Division of the Plasma Science and Fusion Center for a day of lively
scientific discussions and tours of the MIT HEDP experimental facilities. During the day, six MIT PhD students presented
and discussed salient aspects of their HEDP research, which involved the design and building of instrumentation andthe subsequent data collection and analysis from their experiments fielded at NIF, OMEGA, and Z. One of the mostrecent accomplishments, oft discussed during the day, was the implementation at the NIF of the D3He charged-particle
radiographic “backligher.” This platform, which consists of an implosion of a D3He filled capsule, and is the work of PhD
students Hong Sio, Brandon Lahmann, Graeme Sutfcliffe, and Neel Kabadi, under the guidance of MIT scientists Chikang
Li and Fredrick Seguin, and LLNL scientists Ryan Rygg and Sebastien LePape, is able to simultaneously generate intense~ 75 ps pulses of monoenergetic particles of 14.7 MeV and 3.0 MeV protons, and 3.6 MeV alphas and 1.0 MeV tritons.
This set of particles are then used to radiograph the evolution and detailed structure of fields and plasma flows of HEDP
experiments. Very recently, this platform was utilized in two NIF experiments to reveal exquisite details of collisionlessshocks and the properties, hitherto unobservable, of warm-dense matter. Shown above is the HED accelerator facility
where students and staff tested and developed, prior to implementation at the NIF, the radiographic and high-speed
detectors used in these experiments. (From left to right: Chikang Li, Richard Petrasso, Johan Frenje, Alex Zylstra,
Keith LeChien, John Edwards, Hans Rinderknecht, Maria Gatu-Johnson, David Orozco, Hong Sio. Alex Zylstra and Hans
Rinderknecht, PhD students in the HEDP Division, are now Reines and Lawrence postdoctoral Fellows at LANL and LLNL,
respectively. Both obtained critical data for their theses from NIF and OMEGA experiments.)

measurements of the source performance in z-pinch and laser-produced
x-ray sources for radiation effects sciences. Wolter optics can replacepinholes in the SLOS imaging system to provide high-fidelity, time-resolved
gated images. The improved imaging capability will enhance experiments
on material strength and complex hydrodynamics using high resolution
radiography, ICF implosion dynamics and stagnation characterization, andnon-thermal x-ray production.
Time Resolved Diffraction. Time-gated x-ray diffraction will provide timedependent measurements of phase change in materials at high pressure.
Near-term improvements would adapt existing framing cameras to the
TARDIS configuration to provide time-resolved capability (see Figure 5-4).
For the longer term, adapting the SLOS detector for this application would
enable multiple diffraction images over time, allowing the observation of
the evolution of crystal structure. Likewise, x-ray diffraction techniques will
be developed for Z starting with single-frame measurements and evolving
National Nuclear Security Administration43

to multi-frame measurements in later years. Time resolved diffraction will
enable measurement of the kinetics of phase transitions at high pressures andmultiple phase transformations on a single shot (for example, melt-refreeze).
The phasing of the Transformational Diagnostics implementation plan issummarized below. That plan is dependent on resource allocation, which is
subject to change.

5.2

Broad Diagnostics

The “Broad Diagnostic” category includes eight important scientific andengineering efforts that are common to all three facilities but are notcharacterized as transformational. These broad efforts are reviewed by thecommunity at many focused workshops.
Neutron Time of Flight
Neutron time of flight detectors have been used for decades at NNSA ICF/
HED facilities. As the complexity of stagnation physics becomes more
apparent, the NDWG has recognized the importance of increasing both thenumber and the accuracy of the nTOF detectors at the NIF, Z, and OMEGA.
A joint project named ‘Precision nToF’ is being pursued to improve themeasurement accuracy and to understand the information encoded in theneutron emission spectrum from the burn, including the deviations from a
Gaussian shape.
In parallel with an improved understanding of the requirements of nToF,
more of the detectors are being built at the three facilities. This activity isin a variety of phases. A new north-pole nToF is being commissioned on
the NIF in Q3 FY16. An antipodal nTOF and two new shielded lines of sightare being built on OMEGA between now and 2019. A gated nToF will be
installed on Z in FY 2016 and a far field nToF is planned for Z in later years.
These diagnostics will aid in understanding the physics of “stagnation” by
quantifying the kinetic energy in the core of the implosion.
Figure 5-4. The TARDIS captures
diffraction images of a material
under dynamic compression. Thisdata is used to determine the phaseof the material.

Hard X-ray Detection
As the temperature of the plasmas in these facilities increases, the x-ray
emission energy increases. In addition, as the areal density of the plasmas
increases, harder x-rays are needed to probe the plasmas. Unfortunately, thesensitivity of x-ray detectors decreases as the x-ray energy increases because
the x-ray absorption of all materials drops. The problem of sensitivity is
exacerbated for sub-nanosecond detectors, which traditionally need to bethin in order to preserve high time resolution. A broad activity is in place
to test advanced detectors. SNL is developing 3D diodes. National Security
Technologies, LLC and LLNL are jointly developing structured photo-cathodedetectors. Each of these approaches increases the path length of photoninteraction within the detector material without significantly sacrificing
temporal resolution. The goal is accurate data on x-ray emission from higher
temperature plasmas for ICF, on radiography of higher density (areal density)
objects for ICF and HED, and on diagnosing K-shell emission from x-ray
sources for radiation effects science.
Radiation Hardening Against Neutron and Gamma Ray
Backgrounds
As the neutron yield increases on all the ICF facilities and the high energy
Bremsstrahlung x-ray background increases on Z, there is a negative impact
on solid-state, e.g., charge-coupled device (CCD), detectors ranging from a few
bright spots to complete failure. LLNL and commercial vendors are producing
a CCD-like detector (a CMOS focal plane array) that will work at neutronand gamma background levels two orders of magnitude higher than current

44

National ICF Program Framework National Diagnostics Plan

CCDs using a technique called ‘dump and read’. In this technique, the shortlived background from neutrons and gammas is continuously recorded by thedetector but then dumped just prior to recording the x-ray signal from theafterglow of a phosphor that continues to emit after the background radiation
has passed. This type of device will also be available to Z and OMEGA.
These detectors will be able to record data at higher yields and will improve
operational efficiency by requiring less facility reconfiguration for high yield
shots.
Time Dependence of the Stagnation Electron Temperature ThroughX-ray Spectroscopy
The electron temperature during stagnation can be measured from theemission spectrum of high-energy x-rays that pass through the cold material
surrounding the hot stagnating core. X-ray focusing spectrometers fieldedclose to the source with new SLOS detectors and/or streak cameras canmeasure this emission spectrum with up to 20-picosecond resolution. A
new set of spectrometers and x-ray streak cameras that can operate in theharsh neutron and gamma environment inside the target chambers is being
developed for the NIF, OMEGA and Z. The NIF spectrometer and timeresolving detector (x-ray streak camera) should be available in FY 2017 (seeFigure 5-5). Time-integrated focusing spectrometers already exist on Z, andplans exist to couple these to SLOS detectors in the next few years. Like theneutron temporal diagnostic (NTD) below, these spectrometers will measure
the energy input to and energy loss from the stagnating core based on how
quickly the core heats and cools.

Figure 5-5. X-ray spectroscopy on
NIF implosions. A time resolved
spectrometer shows that doped
implosions on NIF emit weak He
like krypton (Kr) lines (left). The
calculated fine structure of the Kr
Heα line is shown (middle). A highresolution focusing spectrometer(right) will resolve fine features in the
two Kr lines shown.

Neutron Temporal Diagnostic
The time history of the neutron emission is measured on OMEGA with therecently upgraded NTD. The diagnostic records the time dependence of the
TN burn to an accuracy of 40 ps with a dynamic range of ~ 100. On OMEGA
the time of peak burn as measured by NTD shows that burn is being quenchedearlier than expected. The importance of this OMEGA measurement has led
to the question of whether a similar diagnostic should be built for the NIF. A
LANL, LLE, MIT, and LLNL group is assessing the benefit and difficulty ofdeveloping a NIF NTD. When successfully fielded, an NTD-like diagnostic
will accurately measure the quenching of burn or, in the case of alpha particle
heating, the peaking of burn at the threshold of ignition.
Pulsed X-ray Calibration Source
Time dependent x-ray detectors on all three facilities need regular calibration
as their response changes on monthly timescales as they are exposed to theharsh environment inside the target chambers of the NIF, Z, and OMEGA.
Making an off-line calibration source with sufficient brightness is difficult
National Nuclear Security Administration45

for some of the facility diagnostics and so facility shots are used for in-situ
calibrations. An SNL/LLNL industry working group has designed a source
bright enough for off-line calibration. In parallel, an LLNL/CEA collaboration
has used an off-line short-pulse ultraviolet laser as an alternate short-pulse
calibration capability. The techniques are being compared.
Curved Crystal Imaging
Z and OMEGA both use a focusing x-ray crystal to image with very narrow
bandwidth x-ray emission or to image x-ray backlit experiments. Based onthese successes, an effort is underway to build a Curved Backlighting Imager(CBI) for the NIF. The very narrow bandwidth will allow the NIF to record
the shape of the ablator close to or at the time of peak burn. In the future,these crystal imagers will be combined with SLOS detectors to provide
narrow-bandwidth, time-resolved, high-spatial-resolution images. The
CBI will measure the effect of time-dependent asymmetry of drive for highconvergence implosions.
Magnetic Field Capability on the NIF
Most of the work on MagLIF is performed on the Z facility using the
Z-Beamlet laser to preheat the fuel. The laser preheat phase of the MagLIF
concept is being studied on OMEGA and will be studied on the NIF, where
higher laser energy and better optical diagnostics are available. A magnetic
field capability is part of the OMEGA facility mainly for academic users
through the National Laser Users’ Facility; this capability will be upgradedfrom 10 Tesla to 30 Tesla. An SNL/LLE/LLNL group is designing a magnetic
field capability of up to 70 Tesla for the NIF. This capability will allow studies
of preheat uniformity in laser-produced plasma for MagLIF as well as studiesof the effect of an applied magnetic field on implosion performance.
Figure 5-6. The NIF nTOF diagnostic
shows for the first time a peak in the
T-T neutron spectrum due to decay
through the the ground state of 5He(seen at 570 nsec in the figure.)

5.3

Local Diagnostics

The “Local Diagnostic” category covers those new and improved diagnostics
principally for one of the three large facilities by using known technologies.
These diagnostics are often campaign specific and associated with theeducation of students. This list of existing local diagnostics is long, in excess
of 100 on OMEGA, 60 on the NIF, and 50 on Z. Local diagnostics evolve andare added more quickly than the transformational or broad diagnostics. Some
examples of further work on local diagnostics include the following.
Optical. This category includes Photon Doppler Velocimetry and the line
VISAR to measure the load current on Z, streaked visible spectroscopy tomeasure the plasma and field strength in the feeds for Z, a sub-aperturebackscatter station to measure the back scatter on OMEGA EP, and enhancing
the backscatter into the beam diagnostics on the NIF.
X-ray. This category includes the MCP in-chamber pinhole imager on Z,
coated x-ray microscopes on the NIF, various in-chamber add on (snouts)
for OMEGA and the NIF, a high-spatial-resolution x-ray streak camera for
the NIF, and 7-8 keV radiography on Z, laser entrance hole imaging andspectroscopy for Z, and Bremsstrahlung MeV x-ray spectrometer to measurelaser plasma coupling on OMEGA EP.
Nuclear. This category includes additional flange neutron activation detectors
on the NIF (example neutron signatures depicted in Figure 5-6), highersensitivity radiochemistry on the NIF. (LANL and GA duplicated a highsensitivity detector for off-line measurements of radiochemical samples fromthe NIF. The original detector system remains at LANL and is used to measureslightly longer-lived isotopes.)

46

National ICF Program Framework Scientific Peer Review andthe 2020 ICF Program Goal

6

6.1

Overview

The principal 2020 goal of the ICF Program is to determine the efficacy of
NIF for achieving ignition and the credible physics scaling to multi-megajoule
fusion yields for each of the major ICF approaches. A key challenge is toclearly demonstrate that ICF has achieved this goal and that in each of theintervening years we are, in fact, on a path to achieve it.
The general 2020 goal specifically maps to each of the approaches in thefollowing manner (reproduced from the IEC section): LID: The 2020 goal is to: 1) demonstrate the efficacy of the NIF forachieving ignition and, if unable to do so, understand why, and 2)
demonstrate the efficacy of physics scaling arguments for multimegajoule fusion yield.
 LDD: The 2020 goal is to: 1) demonstrate an inferred hot spotpressure of 100 gigabars and, if unable to do so, understand why, 2)
understand LPI mitigation and control at the ignition length scale,and 3) demonstrate the efficacy of physics scaling arguments (such ashydrodynamic-equivalence) for multi-megajoule fusion yield.

The principal 2020 goalof the ICF Program is todetermine the efficacy of NIF
for achieving ignition and thecredible physics scaling tomulti-megajoule fusion yields
for each of the major ICF
approaches. A key challenge
is to clearly demonstrate that
ICF has achieved this goal andthat in each of the intervening
years we are, in fact, on apath to achieve it.
 MDD: The 2020 goal is to: 1) demonstrate 100 kJ DT equivalent yield
and, if unable to do so, understand why, and 2) demonstrate the efficacyof physics scaling arguments (i.e., with current) for multi-megajoule
fusion yield.
A “demonstration” of these goals has been achieved by producing aquantitative assessment of and associated evidence for: the state of the assembled fusion plasma at stagnation (see the National
Implosion Stagnation Physics Working Group sidebar on page 49),
 an assessment of factors that explain measured performance deviations
from calculated performance,
 the underlying assumptions for and validity of physics-scalingarguments, and the uncertainties associated with the above.
The demonstration must be subjected to scientific-based peer review.
Peer review is important since technical arguments advanced by such ademonstration would also be advanced for assertions of physics scaling(i.e., scaling to higher laser or pulsed power system energies). Quantifying
uncertainties is also extremely important, as is clearly identifying andbounding the underlying assumptions being made in scaling arguments bothfor the target physics and the driver technology. Together with programmatic
drivers, these assessments provide the framework against which decisions on
future investments can be made.

6.2

Measuring Progress Toward the 2020 Goal

Traditionally, progress towards ignition and assertions of physics scaling
have been evaluated using the Lawson criteria (Pτ), where P is the plasmapressure and τ is the confinement time as a function of temperature T. Morerecently, a Generalized Lawson Parameter was developed1, χ = (Pτ)/(Pτ)ign,
where Pτign ~ 1/T2, as a convenient and informative metric for the proximity
to ignition conditions. Another metric2 is Y dsr2 where Y is the fusion yieldand dsr is the down-scattered neutron ratio defined as Y10-12MeV/Y13-15MeV.
1R. Betti et al., “Thermonuclear ignition in inertial confinement fusion andcomparison with magnetic confinement,” Phys. Plasmas 17, 058102 (2010).
2B. Spears and J.D. Lindl in “Review of the National Ignition Campaign 20092012,” Phys. Plasmas, 21, 020501 (2014).
48

National ICF Program Framework Scientific Peer Review and the 2020 Program Goal

Specific direction for a given ICF approach is guided by complex simulations
which each approach will extrapolate to make assertions regarding physics
scaling, may that be by driver energy, pressure, or some other parameter.
Therefore, a critical evaluation and quantification of uncertainties in theextrapolation is central to this exercise, and to any assessment of the validityof scaling arguments. The evaluation and quantification must go far beyond
simple statements based on the above zero-dimensional or low-dimensionality
parameters, and it must include detailed uncertainty estimates in: the state of the assembled fuel from which scaling is to be done, the simulation models or theory that attempt to reproduce thedemonstrated performance and are used to extrapolate, and the physics models in the simulation tools and the magnitude of theeffects of the physics not included.
In particular, models are often calibrated to match certain important
experimental inputs that have measurement uncertainty that must be
accounted for, such as the implosion velocity. This adds additional challenges
regarding assertions of scaling. Further, it is possible that we will reach a point
where irreducible aleatory uncertainties associated with process control may
dominate our residual prediction uncertainties, again, adding to the challengeof qualifying assertions of physics scaling.
A description of the challenges regarding physics scaling for each approach isdetailed below.

6.3

Specific Needs to Support Physics-Scaling Arguments
Associated with the 2020 Goal

6.3.1

Laser Indirect Drive

Important products of the PRDs are calibrated physics-based simulation toolsthat allow interpolation and extrapolation over parameter space of interest,
replacing empirical models and experimental scaling (see comparison
between calculations and measurements for low- and high-foot in Figure 6-1).
Over time, the goal of the PRDs is to improve the fidelity of the physics models
in those simulation codes as experiments, theory, and computer power
advance.
Driver Target Coupling

Develop a 2D radiation-hydrodynamics model that can reproduce theobserved x-ray drive, spectrum, and symmetry in hohlraums that exhibit low
levels of LPI. Record any remaining experimental calibrations, hypotheses,
and physics uncertainties. Understand the resulting uncertainty in predictionsof these quantities.
Fuel Preconditioning

Understand whether shock velocity and timing measurements are consistent
with the observed x-ray drive spectrum particularly during the rise to peak
power, taking into account experimental uncertainties. Record discrepancies
and develop associated hypotheses.

National Nuclear Security Administration

National Implosion
Stagnation Physics(NISP) Working GroupIn the context of inertial
confinement fusion (ICF),“stagnation” has traditionallybeen thought of as the state of
maximum fuel compression
where kinetic energy has been
converted into thermal energy
and the majority of the fusion
reactions take place. The reality
is that the ‘stagnating’ plasma
remains dynamic: there aremany processes occurring
during this critical phase of
the implosion history. It is
prohibitive to simultaneously
measure a given particle’s (ion,electron, and fusion product)energy distribution as a functionof 3D space and time in an ICF
implosion, we instead form aphysical understanding of astagnated plasma through an
ensemble of highly integrating
diagnostics. The precise“stagnated” state also cannot beeasily simulated with complete
physics, so we typically rely
on models that use physics
approximations.
To improve the understandingof the physics of “stagnation,”
NNSA established the NISP
Working Group in summer 2015.
The NISP has been working
on defining peer-reviewed,
distilled physical picturesof the stagnated fuel andablator/liner for all three ICF
approaches that are consistent
with existing data and informedby simulations. The goal is
to task a national team withpeer-reviewing these physicalpictures, generate hypotheses
for the inconsistencies between
the physical pictures andobservations, and develop a plan
to address these inconsistencies
that may require new
diagnostics, experiments, andanalyses methods.
49

Scientific Peer Review

When the DT fuel is magnetized, another important metric is B∙r, which isa measure of alpha particle trapping in the hot spot with radius r due to themagnetic field with strength B. Together, these provide useful, approximatecross-platform metrics of implosion quality, however, the performance of any
given implosion is not uniquely described by any of these metrics, whether the
performance is 1D or highly distorted.

Implosion

Develop predictive models of hydrodynamic instability on the outside of
the capsule as observed in-flight, seeded by engineering features and native
capsule surface and/or internal structure for ablators of interest. Develop
improved understanding of capsule initial conditions, “seeds.” Record any
remaining experimental calibrations, hypotheses, and physics uncertainties.
Understand the resulting uncertainty in predictions of these quantities.
Develop predictive models of implosion asymmetry as observed in-flight
due to radiation drive asymmetry. Record any remaining experimental
calibrations, hypotheses and physics uncertainties. Understand the resulting
uncertainty in predictions of these quantities.
Stagnation and Burn

Develop full-sphere 3D implosion models that incorporate improvements inmodeling from the other PRDs and best models for hot spot physics. Develop
improved analyses of experimental data and reduce error bars. Compare
synthetic diagnostic signatures with experimental observations, including
an evaluation of uncertainties in both experiment and theory. Record
discrepancies, associated hypotheses, and supporting evidence.
Intrinsic Properties

Figure 6-1. 3D simulations of lowfoot (lower left) and high-foot (upper
right) experiments with comparisons
between simulated and measured
neutron yields.

Understand the resolution and detail required to accurately model high Z
hohlraum emission in non-local thermodynamic equilibrium in the context
of overall hohlraum energetics and spectrum. Develop an improved model foruse in radiation hydrocodes. Record best knowledge of uncertainties in models
of intrinsic properties, and resulting sensitivity of predictions. Assess themagnitude of the impact of kinetic effects and magnetic fields on target physics.
6.3.2

Laser Direct Drive

Implosion plasma scale lengths on OMEGA are ~4 times shorter than on
the NIF for energetically equivalent designs. Nevertheless, OMEGA can beused to study designs that are predicted to reach the same hot-spot pressures
as ignition designs for the NIF that would produce multi-megajoule fusion
yields. A key objective for the IECs is to demonstrate the scaling of hot-spotpressure over conditions available on OMEGA, and LDD-related LPI concernson the NIF (see Figure 6-2 for a comparison of calculations as a function ofcapsule position). A key objective for the PRDs is to determine the credibilityof the physics models contained within the simulation tools.
Testing the physics implicit in LDD design tools will be accomplishedin part by focused science experiments conducted under the PRDs. The
following describes the major five-year goals for the PRDs that are critical forunderpinning scaling arguments for LDD.
Figure 6-2. Implosion hot-spotpressure calculated as a function oftarget offset from target chamber
center. The upper curve shows the
expected performance imposed by
the reduced beam overlap. The lower
curve includes the reduce beam
overlap combined with a laser power
imbalance. The open symbols show
the impact of increasing each ofthese contributions by 2x. The image
shows a meridional cut through thesimulation of the shell areal density
at bang time with a 20-micrometer
offset.

50

National ICF Program Framework Scientific Peer Review and the 2020 Program Goal

Driver-Target Coupling

Validate thermal transport models for the multi-dimensional hydrocodes.
Establish and test scalable models for LPI (SRS, TPD, SBS). Verify mitigation
strategies for CBET at OMEGA and the NIF.
Target Preconditioning

Verify mitigation strategies for hot-electron production and fuel preheating
at the OMEGA and NIF scales. Test scalable models for shock formation,
propagation, and coalescence.
Implosion

Verify the power balance requirements for symmetric high convergence(CR > 20) implosions on OMEGA. Understand the sources of ablator mixing
into the hot-spot.
Stagnation and Burn

Develop measurement techniques to understand fuel compression,confinement, and RKE at peak burn. Use 3D hydro simulations to comparewith and guide quantitative measurements.
Intrinsic and Transport Properties

Develop and validate models for fuel and ablator compressibility,
conductivity, and opacity.
6.3.3

Magnetic Direct Drive

Present simulation capabilities suggest that the MDD approach on the existing
Z pulsed power facility is not capable of achieving multi-megajoule fusion
yields. The requirements to achieve such yields will be defined using the best
available simulation tools. The challenge of determining the credibility ofthese tools is described below. A key objective for the IECs is to demonstrate
the scaling of neutron yield over conditions available on Z. A key objective
for the PRDs is to determine the credibility of the physics models contained
within the simulation tools (see Figure 6-3).
Testing the physics implicit in our design tools will be accomplished in partby focused science experiments conducted under the PRDs. The following
describes the major five-year goals for the PRDs that are critical forunderpinning scaling arguments for MDD.
Driver-Target Coupling

Conduct scaled power-flow experiments under conditions similar to thosepresent on the higher-current facilities predicted today to be necessary toachieve multi-megajoule fusion yields, with the goal of developing predictivemodels for the coupling of such accelerators to a variety of targets.

Figure 6-3. HYDRA calculationsof integrated MagLIF yields as afunction of laser energy coupled to
the fusion fuel (assuming no mix).
The yield from the initial experiments
is shown as horizontal green bars.

National Nuclear Security Administration

51

Target Preconditioning

Demonstrate 30 kJ, magnetized laser heating of fusion gas cell targets on the
NIF, to reduce the need for scaling extrapolations to the conditions needed for
multi-megajoule fusion yields.
Implosion

Demonstrate the ability to model acceleration and deceleration instabilities
using the same codes used to predict the integrated target performance.
Stagnation & Burn

Develop diagnostics, measurements, and models for the stagnation plasma
on Z that will allow us to infer the key variables of interest (ion temperature,magnetization, fuel pressure, P-Tau, fuel contamination, and shape/
uniformity).
Intrinsic & Transport Properties

Determine the validity of models for magnetized electron heat transport andmagnetic flux compression in regimes relevant to MagLIF.

Fixed resources require aprioritization of the body ofwork that will be executed. It
is critical to ensure that thefocus is on the most important
aspects that will lead toachieving the 2020 goal. The
Devil’s Advocate Red Teamwill be instrumental in vetting
the physics-scaling arguments
advanced by the LID, LDD, and
MDD efforts.






6.4

Establishing Devil’s Advocate Red Team toContinuously Evaluate Progress Toward the 2020 Goal

The phase-space one would like to explore through the IECs and PRDs is quite
large for each approach. There are, however, fixed resources which require aprioritization in the body of work that will be executed. As such, it is criticalto ensure that the focus be on the most important aspects that will lead toachieving the 2020 goal. Therefore, the arguments put forward to establish
the prioritization by the LID, LDD, and MDD teams must be subjected toscientific scrutiny all along the way.
To address this, in FY 2016 the ICF Program Director will convene a team ofexperienced and respected technical experts known as the Devil’s Advocate
Red Team (DART). A devil’s advocate is assigned the responsibility of finding
the weaknesses of an argument or claim (a so-called “devil’s opinion” on
the matter). In the same way, this team will be charged with finding any
weaknesses in the program’s technical arguments toward the 2020 goal andof the potential effects of any major facility upgrades or changes in programemphasis. Members of DART will individually report to the Federal Program
Director. The ICF Executives will facilitate the work of DART and willassure full cooperation with DART’s requests and provide prompt, complete
responses to their inquiries. The goal of DART is to: ask harder, more penetrating questions than could be asked by any
external body, assure the soundness of technical cases that underlie statements ofachievement of the 2020 goal and for any other major programmatic
decisions, and assure that the technical case that underlies assertions of physics scaling
and estimates of uncertainty withstand scientific scrutiny.
DART will convene regularly, holding a “tribunal” in which the leads of
the LID, LDD, and MDD efforts will present their arguments. DART will
provide written individual opinions to the ICF Program Director as to theirassessment of progress toward the 2020 goal.

52

National ICF Program Framework ICF-HED Capabilities and the

Next 20 Years of Stockpile Stewardship

7

Initial ICF/HED capability improvements for the science-based SSP were
described in the first SSMP, which was published in 1996. That SSMP included
an extensive technical discussion regarding the rationale for particular ICF/
HED capabilities. Not surprisingly, there are a few differences between what
was discussed then, and what is discussed regularly today. Regarding ICF/
HED capabilities, the following capabilities were listed in the first SSMP:
 the NIF, the Advanced Radiation Source (ARS or X-1), and the Atlas
pulsed power capability under the heading “Program Needs forAssessment and Certification,” Pegasus, PBFA-Z, high explosive pulsed power (HEPP) capabilities,
Atlas, ARS/X-1, Nova, OMEGA, the NIF, Saturn, and BEEF under theheading “Response to Surveillance Issues,” Atlas, the NIF, HERMES, HEPP, Z, Saturn, and ARS/X-1 under
the figure titled “New Capabilities are Needed for Assessment andCertification,” and the ARS/X-1 as an “intermediate step” to a new HED pulsed power
facility called Jupiter under the figure titled “Secondary Assessment
Plan.”The establishment of the SSP
brought about the obvious
question of whether the Nation
could maintain a safe, secure,and effective nuclear deterrent
without nuclear explosive
testing. For the last 20 years,
this has been proven to bepossible.
Over the last 20 years, some of these capabilities were pursued, and somewere to come online “later” in the SSP.

7.1

Summary of Existing Capability Needs for ICF/HED

The June 2014 Ten-Year HED Science Strategic Plan identified capabilities
needed for stockpile stewardship. These include capabilities in the areas ofhydrodynamics under HED conditions, material properties under extreme
dynamic conditions, nuclear physics, TN fusion and burn physics (platforms
and diagnostics delivered by the ICF Program), radiation transport andinteractions of radiation with matter, and neutron, gamma-ray, and x-ray
radiation sources for nuclear survivability and vulnerability assessments.
NNSA’s ICF/HED portfolio addresses these capabilities. Currently, some aresufficient and some are lacking.

7.2

Changes in the Nuclear Security Environment That
Affect Current Thinking

The establishment of the SSP brought about the obvious question ofwhether the Nation could maintain a safe, secure, and effective nuclear
deterrent without nuclear explosive testing. For the last 20 years, this has
been proven to be possible. Today, in addition to continuing this legacy,
additional considerations in the nuclear security environment directly affecthow DOE/NNSA think about ICF/HED-related capability improvements.
These considerations include component aging, increasing preference forreuse or refurbishment of components, environmental concerns that affectmanufacturing capabilities, increasing nuclear proliferation, and a workforce
that no longer has direct nuclear explosive testing experience. Other concernsthat directly impact the way NNSA thinks about future ICF/HED sciencecapability enhancements include: ICF/HED capabilities are routinely requested by a growing set of nonDP nuclear security users.
 The nuclear survivability community has lost capabilities over thelast 20 years. That community is looking for ways that the ICF/HED
portfolio may be used to reconstitute a modern capability to meetchanging requirements.

54

National ICF Program Framework ICF-HED Capabilities and the Next 20 Years of Stockpile Stewardship Laboratory ignition has proven elusive. Ignition remains a major goal.
“High yield” is still a program requirement and requires the pursuit of abalanced program in TN burning plasmas.
 Adversaries and near-peers are catching up and setting bold goals in
ICF and HED science.
 The existing infrastructure is aging, and attracting and retaining
stewards at the NNSA laboratories is becoming more difficult.

7.3

Summary of ICF/HED-Related SSP Needs for the Next
20+ Years

In addition to the activities detailed in the Ten-Year HED Science StrategicPlan, NNSA mission planning efforts over the last 18 months have identified anumber of capability gaps in ICF/HED. These include: new experimental and computational platforms, diagnostics, and data
analysis techniques to probe boost-related physics,
 new experimental and computational platforms and facilities to explore
high-fidelity dynamic materials science on high-hazard materials
serving multiple missions,
 new experimental and computational platforms and potentially new
facilities to probe threat-relevant outputs, environments, and effects
regimes motivated by emerging capabilities that may impact nuclear
survivability requirements,

In 2016, Defense Programs
seeks to develop detailed
SSP plans for the next
20 years that will include
those associated with ICF/HED
capabilities.
 new experimental and computational platforms, and potentially new
facilities to create and apply multi-megajoule fusion yields per the
Directors’ letter, and new experimental and computational platforms, diagnostics, andpotentially new facilities to train and test weapons designers in regimes
relevant to secondary performance.
In 2016, Defense Programs seeks to develop detailed SSP plans for the next
20 years that will include those associated with ICF/HED capabilities.

National Nuclear Security Administration55

http://www.nnsa.energy.gov/icf

Inertial
Fusion && HighHigh Yield
Yield
Inertial Confinement
Confinement Fusion