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The National Ignition Facility and Basic Science

The National Ignition Facility and Basic Science. Richard N. Boyd Science Director, National Ignition Facility May 6, 2006.

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The National Ignition Facility and Basic Science

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  1. The National Ignition Facility and Basic Science Richard N. Boyd Science Director, National Ignition Facility May 6, 2006 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.

  2. NIF has 3 Missions National Ignition Facility BasicScience Stockpile Stewardship FusionEnergy Peer-reviewed Basic Science is a fundamental part of NIF’s go-forward plan R. Boyd 04/18/07

  3. Our vision: open NIF to the outside scientific community to pursue frontier HED 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 R. Boyd 04/18/07

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  6. NIF’s Unprecedented Scientific Environments: •T >108 K matter temperature • r >103 g/cc density Those are both 7x what the Sun does! Helium burning, stage 2 instellar evolution, occurs at 2x108 K! • rn = 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! R. Boyd 04/18/07

  7. NIF flux (cm-2s-1) vs other neutron sources 1040 1020 100 1033-36{ Supernovae Neutrons/cm2•s 1014-16{ 1013-15{ 108-9{ LANSCE/WNR Reactor SNS NIF R. Boyd 04/18/07

  8. The NRC committee on HEDP issued the “X-Games” report detailing this new science frontier Findings: • 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 is the premier facility for exploring extreme conditions of HEDP R. Boyd 04/18/07

  9. The NRC committee on the Physics of the Universe highlighted the new frontier of HED Science Eleven science questions for the new century: 2. What is the nature of dark energy? — Type 1A SNe (burn, hydro, rad flow, EOS, opacities) 4. Did Einstein have the last word on gravity? — Accreting black holes (photoionized plasmas, spectroscopy) 6. How do cosmic accelerators work and what are they accelerating? —Cosmic rays (strong field physics, nonlinear plasma waves) 8. Are there new states of matter at exceedingly high density and temperature? —Neutron star interior (photoionized plasmas, spectroscopy, EOS) NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES 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) • HEDP provides crucial experiments to interpret astrophysical observations R. Boyd 04/18/07

  10. Core-collapse supernova explosion mechanisms remain uncertain • SN observations suggest rapid core penetration to the “surface” • This observed turbulent core inversion is not yet fully understood Jet model Standard (spherical shock) model Density t = 1800 sec 9 x 109cm 1012cm [Kifonidis et al., AA. 408, 621 (2003)] • 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 6 x 109cm [Khokhlov et al., Ap.J.Lett. 524, L107 (1999)] R. Boyd 04/18/07

  11. Three university teams are starting to prepare for NIF shots in unique regimes of HED physics Astrophysics -hydrodynamics Planetary physics - EOS Nonlinear optical physics - LPI Raymond Jeanloz, PI, UC Berkeley Thomas Duffy, Princeton U. Russell Hemley, Carnegie Inst. Yogendra Gupta, Wash. State U. Paul Loubeyre, U. Pierre & Marie Curie, and CEA LLNL EOS team Christoph Niemann, PI, UCLA NIF Professor Chan Joshi, UCLA Warren Mori, UCLA Bedros Afeyan, Polymath David Montgomery, LANL Andrew Schmitt, NRL LLNL LPI team 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 R. Boyd 04/18/07

  12. Comparison of 3He(4He,)7Be measured at an accelerator lab and using NIF Accelerator-Based Experiments NIF-Based Experiments CH 3He(4He,)7Be Ablator 0.6 DT S-Factor (keV.barn) Resonance Ice 10173He atoms 0.4 DT Gas Gamow window 0.2 0 400 800 E (keV)   High Count rate (3x105 atoms/shot) Small, manageable screening Energy window is better (a bit high) Integral experiment 7Be background Mono-energetic Low event rate at low energies Significant screening corrections needed Not performed at relevant energies  X  X X X X R. Boyd 04/18/07

  13. Abundance after  decay 80 100 120 140 160 180 200 220 Mass Number (A) A unique NIF opportunity: Study ofThree-Body Reactions in the r-Process • 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 a+a+n9Be reaction R. Boyd 04/18/07

  14. a+a+n9Be is the “Gatekeeper” for the r-Process • If this reaction is strong, 9Be becomes abundant, a+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 9Be a During its 10-16 s half-life, a 8Be can capture a neutron to make 9Be, in the r-process environment, andeven in the NIF target 8Be a n • 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 R. Boyd 04/18/07

  15. The NRC committee on the Physics of the Universe highlighted the new frontier of HED Science Eleven science questions for the new century: 2. What is the nature of dark energy? — Type 1A SNe (burn, hydro, rad flow, EOS, opacities) 4. Did Einstein have the last word on gravity? — Accreting black holes (photoionized plasmas, spectroscopy) 6. How do cosmic accelerators work and what are they accelerating? —Cosmic rays (strong field physics, nonlinear plasma waves) 8. Are there new states of matter at exceedingly high density and temperature? —Neutron star interior (photoionized plasmas, spectroscopy, EOS) NATIONAL RESEARCH COUNCIL OF THE NATIONAL ACADEMIES 10. How were the elements from iron to uranium made and ejected? —Core-collapse SNe (reactions off excited states, turbulent hydro, rad flow) • HEDP provides crucial experiments to interpreting astrophysical observations • We envision that NIF will play a key role in these measurements R. Boyd 04/18/07

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  17. 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 • 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 From http://www.msnbc.msn.com/id/11463498/ • Burrows’ solution hasn’t been accepted by everyone; it’s very different from any previously proposed R. Boyd 04/18/07

  18. Opacity experiments on iron led to an improved understanding of Cepheid Variable pulsation 2 OPAL, Z = 0.02 • 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” Fe M shell Cox Tabor 0.74 Los Alamos, Z = 0.02 H, OPAL, Z = 0.00 6M H He 1 He+ OPAL 5M Fe L shell and Log kR (cm2/g) 0.72 P1 / P0 C, O, Ne K shell 4M 4M 5M Ar, Fe K shell 0 6M 7M 0.70 Observations 1 3 5 7 -1 4 5 6 7 8 P0 (days) Log T(K) [Rogers & Iglesias, Science 263,50 (1994); Da Silva et al., PRL 69, 438 (1992)] R. Boyd 04/18/07

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