The National Ignition Facility and Basic Science

Work performed under the auspices of the U.S. Department of Energy

by the University of California, Lawrence Livermore National Laboratory

under Contract No. W-7405-ENG-48.

Richard N. Boyd

Science Director, National Ignition Facility

May 6, 2006

NIF-0307-13446.ppt R. Boyd 04/18/07 2

NIF has 3 Missions

National Ignition Facility

Peer-reviewed Basic Science is a fundamental part of NIF’s go-forward plan

StockpileStewardship

BasicScience

FusionEnergy

NIF-0307-13446.ppt R. Boyd 04/18/07 3

Our vision: open NIF to the outsidescientific community to pursue frontierHED laboratory science

Element formation in stars

The Big Bang

Planetary system formation

Forming Earth-like planets

Chemistry of life

[http://www.nas.edu/bpa/reports/cpu/index.html

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NIF-0307-13446.ppt R. Boyd 04/18/07 5

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NIF’s Unprecedented Scientific Environments:

• T >108 K matter temperature • ! >103 g/cc density

Those are both 7x what the Sun does! Helium burning, stage 2 instellar evolution, occurs at 2x108 K!

• !n = 1026 neutrons/cc

Core-collapse Supernovae, collidingneutron stars, operate at ~1021!

• Electron Degenerate conditions Rayleigh-Taylor instabilities for (continued) laboratory study.

These apply to Type Ia Supernovae!

• Pressure > 1011 barOnly need ~Mbar in shocked hydrogento study the EOS in Jupiter & Saturn

These certainly qualify as “unprecedented.” And Extreme!

NIF-0307-13446.ppt R. Boyd 04/18/07 7

NIF flux (cm-2s-1) vs other neutron sources

LANSCE/WNR Reactor SNS NIF

1033-36{

1014-16{

108-9{

1040

1020

100

Ne

utr

on

s/c

m2•s

1013-15{

Supernovae

NIF-0307-13446.ppt R. Boyd 04/18/07 8

The NRC committee on HEDP issued the “X-Games” report detailing this new science frontier

Findings:

NIF is the premier facility for exploring extreme conditions of HEDP

• HEDP offers frontier researchopportunities in:

- Plasma physics

- Laser and particle beam physics

- Condensed matter and materials science

- Nuclear physics

- Atomic and molecular physics

- Fluid dynamics

- Magnetohydrodynamics

- Astrophysics

NIF-0307-13446.ppt R. Boyd 04/18/07 9

The NRC committee on the Physics of the Universehighlighted the new frontier of HED Science

• HEDP provides crucial experiments to interpret astrophysical observations

Eleven science questions for the new century:

2. What is the nature of dark energy? — Type 1A SNe (burn, hydro, rad flow, EOS, opacities)

6. How do cosmic accelerators work and

what are they accelerating?— Cosmic rays (strong field physics, nonlinear

plasma waves)

4. Did Einstein have the last word on gravity? — Accreting black holes (photoionized

plasmas, spectroscopy)

8. Are there new states of matter at exceedingly

high density and temperature?— Neutron star interior (photoionized plasmas,

spectroscopy, EOS)

10. How were the elements from iron to

uranium made and ejected?— Core-collapse SNe (reactions off excited states,

turbulent hydro, rad flow, r-process)

NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES

NIF-0307-13446.ppt R. Boyd 04/18/07 10

Core-collapse supernova explosionmechanisms remain uncertain

6 x 109cm

• SN observations suggest rapid core penetration to the “surface”

• This observed turbulent core inversion is not yet fully understood

Standard (spherical shock) model

[Kifonidis et al., AA. 408, 621 (2003)]

Densityt = 1800 sec

Jet model

[Khokhlov et al., Ap.J.Lett. 524,

L107 (1999)]

• Pre-supernova structure is multilayered

• Supernova explodes by a strong shock

• Turbulent hydrodynamic mixing results

• Core ejection depends on this turbulent hydro.

• Accurate 3D modeling is required, but difficult

• Scaled 3D testbed experiments are possible

1012cm

9 x

10

9c

m

NIF-0307-13446.ppt R. Boyd 04/18/07 11

Three university teams are starting to preparefor NIF shots in unique regimes of HED physics

Planetaryphysics - EOS

Paul Drake, PI, U. of Mich.David Arnett, U. of Arizona, Adam Frank, U. of Rochester, Tomek Plewa, U. of Chicago,

Todd Ditmire, U. Texas-Austin

LLNL hydrodynamics team

Raymond Jeanloz, PI,

UC BerkeleyThomas Duffy, Princeton U.

Russell Hemley, Carnegie Inst.Yogendra Gupta, Wash. State U.Paul Loubeyre, U. Pierre & Marie

Curie, and CEALLNL EOS team

Christoph Niemann, PI, UCLA NIF ProfessorChan Joshi, UCLAWarren Mori, UCLA

Bedros Afeyan, PolymathDavid Montgomery, LANLAndrew Schmitt, NRL

LLNL LPI team

Astrophysics -hydrodynamics

Nonlinear opticalphysics - LPI

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Comparison of 3He(4He,")7Be measured atan accelerator lab and using NIF

NIF-Based Experiments

E (keV)

0.2

0.4

Gamow window

0 400 800

S-F

ac

tor

(ke

V. b

arn

)

Resonance

Accelerator-Based Experiments

Mono-energetic

Low event rate at low energies

Significant screening correctionsneeded

Not performed at relevant energies

High Count rate (3x105 atoms/shot)

Small, manageable screening

Energy window is better (a bit high)

Integral experiment

7Be background

1017 3Heatoms

CH

Ablator

DT

Ice

DT Gas

0.63He(4He,")7Be

!X

X

X

!

!

!

X

X

NIF-0307-13446.ppt R. Boyd 04/18/07 13

• Thermonuclear Reaction Rates between species i and j are of the form:

• S factors are extrapolated to the relevant stellar Gamow ‘weighting’regions from higher energy experimental data – laboratory ‘cold’electron screening effects are significant

• Thermonuclear reactions can be observed in ‘passive’ NIF implosions oras by products of the temperature runaway in d + t burn -butmeasurements challenging!

2/1)/()(~ pGe

SvR

p

pij

ijfij

!!"

!

!##

$=%&

~ 6 x 106 reactions15N(p, #)12C

~ 3 x 105 reactions3He(#,") 7Be

~ 4 x 104 reactions7Be(p,")8B

~ 108 reactions at 8 keV in 20 ps (1017

initial nuclei, note ‘targets’)

3He(3He,2p)#

Stellar Astrophysics at NIF: Measurements of BasicThermonuclear Reactions

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A unique NIF opportunity: Study ofThree-Body Reactions in the r-Process

Abundan

ce a

fter

$%

#%

dec

ay

60 80 100 120 140 160 180 200 220Mass Number (A)

• Currently believed to take place in

supernovae, but we don’t know for sure

• r-process abundances depend on:

— Weak decay rates far from stability

— Nuclear masses far from stability

• The cross section for the #+#+n&9Be

reaction

NIF-0307-13446.ppt R. Boyd 04/18/07 15

#

#

8BeDuring its 10-16 s half-

life, a 8Be can capture

a neutron to make 9Be,

in the r-process

environment, and even

in the NIF target n

9Be

• If this reaction is strong, 9Be becomes abundant, #+9Be& 12C+n is

frequent, and the light nuclei will all have all been captured into theseeds by the time the r-process seeds get to ~Fe

• If it’s weak, less 12C is made, and the seeds go up to mass 100 u orso; this seems to be what a successful r-process (at the neutron starsite) requires

• The NIF target would be a mixture of 2H and 3H, to make the neutrons, with some 4He (and more 4He will be made during ignition). This type of experiment can’t be done with any other facility that has ever existed

#+#+n&9Be is the “Gatekeeper” for the r-Process

NIF-0307-13446.ppt R. Boyd 04/18/07 16

• HEDP provides crucial experiments to interpreting astrophysical observations

• We envision that NIF will play a key role in these measurements

Eleven science questions for the new century:

2. What is the nature of dark energy? — Type 1A SNe (burn, hydro, rad flow, EOS, opacities)

6. How do cosmic accelerators work and

what are they accelerating?— Cosmic rays (strong field physics, nonlinear

plasma waves)

4. Did Einstein have the last word on gravity? — Accreting black holes (photoionized

plasmas, spectroscopy)

8. Are there new states of matter at exceedingly

high density and temperature?— Neutron star interior (photoionized plasmas,

spectroscopy, EOS)

10. How were the elements from iron to

uranium made and ejected?— Core-collapse SNe (reactions off excited states,

turbulent hydro, rad flow)

NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES

The NRC committee on the Physics of the Universehighlighted the new frontier of HED Science

NIF-0307-13446.ppt R. Boyd 04/18/07 17

NIF-0307-13446.ppt R. Boyd 04/18/07 18

Core-collapse supernova explosionmechanisms remain uncertain

• A new model of Supernova explosions:

from Adam Burrows et al.

• A cutaway view shows the inner regions

of a star 25 times more massive than the

sun during the last split second before

exploding as a SN, as visualized in a

computer simulation. Purple represents

the star’s inner core; Green (Brown)

represents high (low) heat content

From http://www.msnbc.msn.com/id/11463498/

• In the Burrows model, after about half a

second, the collapsing inner core begins

to vibrate in “g-mode” oscillations. These

grow, and after about 700 ms, create

sound waves with frequencies of 200

to 400 hertz. This acoustic power couples

to the outer regions of the star with high

efficiency, causing the SN to explode

• Burrows’ solution hasn’t been accepted by everyone; it’s very different from any previously proposed

NIF-0307-13446.ppt R. Boyd 04/18/07 19

Opacity experiments on iron led to an improvedunderstanding of Cepheid Variable pulsation

• The measured opacities of Fe under relevant conditions were largerthan originally calculated

• New OPAL simulations reproduced the data

• The new opacity simulations allowed Cepheid Variable pulsations tobe correctly modeled

• “Micro input physics” affecting the “macro output dynamics”

[Rogers & Iglesias, Science 263,50 (1994); Da Silva et al., PRL 69, 438 (1992)]

P0 (days)

P1

/ P

0

0.74

0.70

0.72OPAL

Cox Tabor

6M!!

5M!!

4M!!4M

!! 5M!!

6M!!

7M!

!Observations

Log T(K)

Lo

g k

R (cm

2/g

)

Fe M shell

Fe L shell andC, O, Ne K shell

H

He+

H,He

Los Alamos, Z = 0.02OPAL, Z = 0.00

OPAL, Z = 0.02

Ar, Fe K shell

2

1

0

-11 3 5 74 5 6 7 8