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
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NIF has 3 Missions
National Ignition Facility
Peer-reviewed Basic Science is a fundamental part of NIF’s go-forward plan
Stockpile Stewardship
BasicScience
FusionEnergy
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Our vision: open NIF to the outside scientific community to pursue frontier HED laboratory science
Element formation in stars
The Big BangPlanetary system formation
Forming Earth-like planets
Chemistry of life
[http://www.nas.edu/bpa/reports/cpu/index.html
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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, colliding neutron 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 hydrogen to study the EOS in Jupiter & Saturn
These certainly qualify as “unprecedented.” And Extreme!
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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
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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
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The NRC committee on the Physics of the Universe highlighted 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
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Core-collapse supernova explosion mechanisms 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
109 c
m
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Three university teams are starting to prepare for 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, UCLABedros Afeyan, PolymathDavid Montgomery, LANLAndrew Schmitt, NRLLLNL LPI team
Astrophysics -hydrodynamics
Nonlinear optical physics - LPI
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Comparison of 3He(4He,)7Be measured at an accelerator lab and using NIF
NIF-Based Experiments
E (keV)
0.2
0.4
Gamow window
0 400 800
S-F
acto
r (k
eV. b
arn
)
Resonance
Accelerator-Based Experiments
Mono-energetic
Low event rate at low energies
Significant screening corrections needed
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
CHAblator
DT
Ice
DT Gas
0.63He(4He,)7Be
XX
X
XX
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A unique NIF opportunity: Study ofThree-Body Reactions in the r-Process
Abu
ndan
ce a
fter
d
ecay
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 ++n9Be reaction
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8Be
During 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 the seeds 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 or so; this seems to be what a successful r-process (at the neutron star site) 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
+n9Be is the “Gatekeeper” for the r-Process
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• 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 Universe highlighted the new frontier of HED Science
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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
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Opacity experiments on iron led to an improved understanding of Cepheid Variable pulsation
• The measured opacities of Fe under relevant conditions were larger than originally calculated
• New OPAL simulations reproduced the data
• The new opacity simulations allowed Cepheid Variable pulsations to be 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
4M4M 5M6M
7M
Observations
Log T(K)
Lo
g k
R (c
m2 /
g)
Fe M shell
Fe L shell andC, O, Ne K shell
HHe+
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
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