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
NIF-0307-13446.ppt R. Boyd 04/18/07 6
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
NIF-0307-13446.ppt R. Boyd 04/18/07 12
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
NIF-0307-13446.ppt R. Boyd 04/18/07 14
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 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