-
[show abstract]
[hide abstract]
ABSTRACT: A nitrogen gas Raman cell system has been constructed to shift a 70 J 527 nm
laser beam to 600 nm with 20 J of energy. The 600 nm probe and a 200J, 527 nm
pump beam were optically mixed in a laser produced (gas jet) plasma. The
beating of the two laser beams formed a ponderomotive force that can drive
Kinetic Electrostatic Electron Nonlinear (KEEN) waves discovered in
Vlasov-Poisson simulations by Afeyan et al [1,2]. KEEN waves were detected in
these experiments where traditional plasma theory would declare there to be a
spectral gap (ie no linear waves possible). The detection was done using
Thomson scattering with probe wavelengths of both 351 nm and 263.5 nm.
11/2012;
-
M B Schneider,
N B Meezan,
S S Alvarez,
J Alameda,
S Baker,
P M Bell,
D K Bradley,
D A Callahan,
J R Celeste,
E L Dewald, [......],
J E Ralph,
J Robinson,
R Soufli,
L J Suter,
A T Teruya,
C A Thomas,
R P Town,
S P Vernon,
K Widmann,
B K Young
[show abstract]
[hide abstract]
ABSTRACT: Hohlraums are employed at the national ignition facility to convert laser energy into a thermal x-radiation drive, which implodes a fusion capsule, thus compressing the fuel. The x-radiation drive is measured with a low spectral resolution, time-resolved x-ray spectrometer, which views the region around the hohlraum's laser entrance hole. This measurement has no spatial resolution. To convert this to the drive inside the hohlraum, the size of the hohlraum's opening ("clear aperture") and fraction of the measured x-radiation, which comes from this opening, must be known. The size of the clear aperture is measured with the time integrated static x-ray imager (SXI). A soft x-ray imaging channel has been added to the SXI to measure the fraction of x-radiation emitted from inside the clear aperture. A multilayer mirror plus filter selects an x-ray band centered at 870 eV, near the peak of the x-ray spectrum of a 300 eV blackbody. Results from this channel and corrections to the x-radiation drive are discussed.
The Review of scientific instruments 10/2012; 83(10):10E525. · 1.52 Impact Factor
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A S Moore,
T M Guymer, J L Kline,
J Morton,
M Taccetti,
N E Lanier,
C Bentley,
J Workman,
B Peterson,
K Mussack,
J Cowan,
R Prasad,
M Richardson,
S Burns,
D H Kalantar,
L R Benedetti,
P Bell,
D Bradley,
W Hsing,
M Stevenson
[show abstract]
[hide abstract]
ABSTRACT: A soft x-ray transmission grating spectrometer has been designed for use on high energy-density physics experiments at the National Ignition Facility (NIF); coupled to one of the NIF gated x-ray detectors it records 16 time-gated spectra between 250 and 1000 eV with 100 ps temporal resolution. The trade-off between spectral and spatial resolution leads to an optimized design for measurement of emission around the peak of a 100-300 eV blackbody spectrum. Performance qualification results from the NIF, the Trident Laser Facility and vacuum ultraviolet beamline at the National Synchrotron Light Source, evidence a <100 μm spatial resolution in combination with a source-size limited spectral resolution that is <10 eV at photon energies of 300 eV.
The Review of scientific instruments 10/2012; 83(10):10E132. · 1.52 Impact Factor
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T Döppner,
E L Dewald,
L Divol,
C A Thomas,
S Burns,
P M Celliers,
N Izumi, J L Kline,
G Lacaille,
J M McNaney,
R R Prasad,
H F Robey,
S H Glenzer,
O L Landen
[show abstract]
[hide abstract]
ABSTRACT: We have fielded a hard x-ray (>100 keV) imager with high aspect ratio pinholes to measure the spatially resolved bremsstrahlung emission from energetic electrons slowing in a plastic ablator shell during indirectly driven implosions at the National Ignition Facility. These electrons are generated in laser plasma interactions and are a source of preheat to the deuterium-tritium fuel. First measurements show that hot electron preheat does not limit obtaining the fuel areal densities required for ignition and burn.
The Review of scientific instruments 10/2012; 83(10):10E508. · 1.52 Impact Factor
-
T Ma,
N Izumi,
R Tommasini,
D K Bradley,
P Bell,
C J Cerjan,
S Dixit,
T Döppner,
O Jones, J L Kline, [......],
P K Patel,
R R Prasad,
J Ralph,
S P Regan,
V A Smalyuk,
P T Springer,
L Suter,
R P J Town,
S V Weber,
S H Glenzer
[show abstract]
[hide abstract]
ABSTRACT: Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.
The Review of scientific instruments 10/2012; 83(10):10E115. · 1.52 Impact Factor
-
Sebastien Hamel,
Lorin X. Benedict,
Peter M. Celliers,
M. A. Barrios,
T. R. Boehly,
G. W. Collins,
Tilo Döppner,
J. H. Eggert,
D. R. Farley,
D. G. Hicks, J. L. Kline,
A. Lazicki,
S. LePape,
A. J. Mackinnon,
J. D. Moody,
H. F. Robey,
Eric Schwegler,
Philip A. Sterne
[show abstract]
[hide abstract]
ABSTRACT: We report the computation and measurement of the equation of state of a plastic with composition CH1.36. The computational scheme employed is density functional theory based molecular dynamics, at the conditions: 1.8 g/cm3 <ρ<10 g/cm3, and 4000 K <T< 100 000 K. Experimental measurements are of the shock speeds in a geometry in which the plastic is directly abutting a different material, liquid deuterium, from which release wave behavior in the plastic can be deduced. After fitting our computed pressure and internal energy with a Mie-Grüneisen free energy model, we predict the principal shock Hugoniot and various shock-and-release paths and show that they agree with both recently published laser-shock data and our new data regarding the shock speeds on release. We also establish that, at least in the particular (ρ,T) range considered, the equation of state of this complex two-component material is well described by an equal pressure and temperature mixture of pure C and H equations of state with a composition-weighted additive-volume assumption. This observation, together with our fit to the limited-range simulation data, can form the basis for the construction of an accurate wide-range equation of state model for this plastic. Implications for its use as an ablator in inertial confinement fusion capsules are discussed.
Phys. Rev. B. 09/2012; 86(9).
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D A Callahan,
N B Meezan,
S H Glenzer,
A J MacKinnon,
L R Benedetti,
D K Bradley,
J R Celeste,
P M Celliers,
S N Dixit,
T Doumlppner, [......],
L J Atherton,
G A Kyrala, J L Kline,
R E Olson,
D Edgell,
S P Regan,
A Nikroo,
H Wilkins,
J D Kilkenny,
A S Moore
[show abstract]
[hide abstract]
ABSTRACT: Achieving inertial confinement fusion ignition requires a symmetric, high velocity implosion. Experiments show that we can reach 95 plusmn 5% of the required velocity by using a 420 TW, 1.6 MJ laser pulse. In addition, experiments with a depleted uranium hohlraum show an increase in capsule performance which suggests an additional 18 plusmn 5 mum/ns of velocity with uranium hohlraums over gold hohlraums. Combining these two would give 99 plusmn 5% of the ignition velocity. Experiments show that we have the ability to tune symmetry using crossbeam transfer. We can control the second Legendre mode (P2) by changing the wavelength separation between the inner and outer cones of laser beams. We can control the azimuthal m = 4 asymmetry by changing the wavelength separation between the 23.5 and 30 degree beams on NIF. This paper describes our ldquofirst passrdquo tuning the implosion velocity and shape on the National Ignition Facility laser [Moses et al., Phys. Plasmas, 16, 041006 (2009)].
Physics of Plasmas 05/2012; 19(5):056305 (9 pp.). · 2.15 Impact Factor
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L. Yin,
B.J. Albright,
H.A. Rose,
K.J. Bowers,
B. Bergen,
R.K. Kirkwood,
D.E. Hinkel,
A.B. Langdon,
P. Michel,
D.S. Montgomery, J.L. Kline
Physics of Plasmas 05/2012; 19(5):056304. · 2.15 Impact Factor
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S P Regan,
R Epstein,
B A Hammel,
L J Suter,
J Ralph,
H Scott,
M A Barrios,
D K Bradley,
D A Callahan,
C Cerjan, [......],
J J MacFarlane,
R C Mancini,
R L McCrory,
N B Meezan,
D D Meyerhofer,
A Nikroo,
K J Peterson,
T C Sangster,
P Springer,
R P J Town
[show abstract]
[hide abstract]
ABSTRACT: Ignition of an inertial confinement fusion (ICF) target depends on the formation of a central hot spot with sufficient temperature and areal density. Radiative and conductive losses from the hot spot can be enhanced by hydrodynamic instabilities. The concentric spherical layers of current National Ignition Facility (NIF) ignition targets consist of a plastic ablator surrounding a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. The Rev. 5 ablator is doped with Ge to minimize preheat of the ablator closest to the DT ice caused by Au M-band emission from the hohlraum x-ray drive [D. S. Clark et al., Phys. Plasmas 17, 052703 (2010)]. Richtmyer-Meshkov and Rayleigh-Taylor hydrodynamic instabilities seeded by high-mode (50 < l < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase [B. A. Hammel et al., Phys. Plasmas 18, 056310 (2011)]. As the shell decelerates, it compresses the fuel vapor, forming a hot spot. K-shell line emission from the ionized Ge that has penetrated into the hot spot provides an experimental signature of hot-spot mix. The Ge emission from tritium-hydrogen-deuterium (THD) and deuterium-tritium (DT) cryogenic targets and gas-filled plastic-shell capsules, which replace the THD layer with a mass-equivalent CH layer, was examined. The inferred amount of hot-spot-mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code [J. J. MacFarlane et al., High Energy Density Phys. 3, 181 (2006)], is typically below the 75-ng allowance for hot-spot mix [S. W. Haan et al., Phys. Plasmas 18, 051001 (2011)]. Predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3694057]
Physics of Plasmas 05/2012; 19(5). · 2.15 Impact Factor
-
C. C. Kuranz,
H.-S. Park,
B. A. Remington,
R. P. Drake,
A. R. Miles,
H. F. Robey,
J. D. Kilkenny,
C. J. Keane,
D. H. Kalantar,
C. M. Huntington, [......],
B. Maddox,
B. Young, J. L. Kline,
G. Kyrala,
T. Plewa,
J. C. Wheeler,
W. D. Arnett,
R. J. Wallace,
E. Giraldez,
A. Nikroo
[show abstract]
[hide abstract]
ABSTRACT: The National Ignition Facility (NIF) is capable of creating new and novel high-energy-density (HED) systems relevant to astrophysics.
Specifically, a system could be created that studies the effects of a radiative shock on a hydrodynamically unstable interface.
These dynamics would be relevant to the early evolution after a core-collapse supernova of a red supergiant star. Prior to
NIF, no HED facility had enough energy to perform this kind of experiment. The experimental target will include a 340 μm predominantly
plastic ablator followed by a low-density SiO2 foam. The interface will have a specific, machined pattern that will seed hydrodynamic instabilities. The growth of the instabilities
in a radiation-dominated environment will be observed. This experiment requires a ≥300eV hohlraum drive and will be diagnosed
using point projection pinhole radiography, which have both been recently demonstrated on NIF.
KeywordsLaboratory astrophysics–National Ignition Facility–Radiation hydrodynamics–Hydrodynamic instability–Radiative shocks
Astrophysics and Space Science 04/2012; 336(1):207-211. · 1.69 Impact Factor
-
J D Moody,
P Michel,
L Divol,
R L Berger,
E Bond,
D K Bradley,
D A Callahan,
E L Dewald,
S Dixit,
M J Edwards, [......],
M B Schneider,
D J Strozzi,
L J Suter,
C A Thomas,
R P J Town,
K Widmann,
E A Williams,
L J Atherton,
S H Glenzer,
E I Moses
[show abstract]
[hide abstract]
ABSTRACT: Laser redirection by cross-beam power transfer in a plasma is an important example of a nonlinear optics process which uses laser-plasma instabilities to one's advantage. We have demonstrated this in a hohlraum plasma at the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. A four-wave mixing process causes laser power in multiple beams to change direction and add to the laser power of a selected beam. The process is controlled by setting the wavelength separation of the interacting laser beams. This technique provides a method to remotely re-point or combine high-powered laser beams without the need of local optical apparatus.
Nature Physics 04/2012; 8(4):344-349. · 18.97 Impact Factor
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A J Mackinnon, J L Kline,
S N Dixit,
S H Glenzer,
M J Edwards,
D A Callahan,
N B Meezan,
S W Haan,
J D Kilkenny,
T Doumlppner, [......],
B Vanwonterghem,
R L Kauffman,
S Batha,
D W Larson,
R J Fortner,
D H Schneider,
J D Lindl,
R W Patterson,
L J Atherton,
E I Moses
[show abstract]
[hide abstract]
ABSTRACT: The National Ignition Facility has been used to compress deuterium-tritium to an average areal density of ~1.0plusmn0.1 g cm -2, which is 67% of the ignition requirement. These conditions were obtained using 192 laser beams with total energy of 1-1.6 MJ and peak power up to 420 TW to create a hohlraum drive with a shaped power profile, peaking at a soft x-ray radiation temperature of 275-300 eV. This pulse delivered a series of shocks that compressed a capsule containing cryogenic deuterium-tritium to a radius of 25-35 mum. Neutron images of the implosion were used to estimate a fuel density of 500-800 g cm -3.
Physical Review Letters 01/2012; 108(21):215005 (5 pp.). · 7.37 Impact Factor
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P M Celliers,
H F Robey,
T R Boehly,
E Alger,
S Azevedo,
L V Berzins,
S D Bhandarkar,
M W Bowers,
S J Brereton,
D Callahan, [......],
K Widmann,
C Widmayer,
B K Young,
L J Atherton,
G W Collins,
O L Landen,
J D Lindl,
B J MacGowan,
D D Meyerhofer,
E I Moses
[show abstract]
[hide abstract]
ABSTRACT: An experimental campaign to tune the initial shock compression sequence of capsule implosions on the National Ignition Facility (NIF) was initiated in late 2010. The experiments use a NIF ignition-scale hohlraum and capsule that employs a reentrant cone to provide optical access to the shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of the shock sequence is diagnosed with velocity interferometry that provides target performance data used to set the pulse shape for ignition capsule implosions that follow. From the start, these measurements yielded significant new information on target performance, leading to improvements in the target design. We describe the results and interpretation of the initial tuning experiments.
10/2011
-
J.D. Lindl,
L.J. Atherton,
P.A. Amednt,
S. Batha,
P. Bell,
R.L. Berger,
R. Betti,
D.L. Bleuel,
T.R. Boehly,
D.K. Bradley, [......],
R. Vesey,
S.V. Weber,
P.J. Wegner,
K. Widman,
C.C. Widmayer,
M. Wilke,
H.L. Wilkens,
E.A. Williams,
D.C. Wilson,
B.K. Young
[show abstract]
[hide abstract]
ABSTRACT: The National Ignition Facility at Lawrence Livermore National Laboratory was formally dedicated in May 2009. The hohlraum energetics campaign with all 192 beams began shortly thereafter and ran until early December 2009. These experiments explored hohlraum-operating regimes in preparation for experiments with layered cryogenic targets. The hohlraum energetic series culminated with an experiment that irradiated an ignition scale hohlraum with 1 MJ. The results demonstrated the ability to produce a 285 eV radiation environment in an ignition scale hohlraum while meeting ignition requirements for symmetry, backscatter and hot electron production. Complementary scaling experiments indicate that with ~1.3 MJ, the capsule drive temperature will reach 300 eV, the point design temperature for the first ignition campaign. Preparation for cryo-layered implosions included installation of a variety of nuclear diagnostics, cryogenic layering target positioner, advanced optics and facility modifications needed for tritium operations and for routine operation at laser energy greater than 1.3 MJ. The first cyro-layered experiment was carried out on 29 September 2010. The main purpose of this shot was to demonstrate the ability to integrate all of the laser, target and diagnostic capability needed for a successful cryo-layered experiment. This paper discusses the ignition point design as well as findings and conclusions from the hohlraum energetics campaign carried out in 2009. It also provides a brief summary of the initial cryo-layered implosion.
Nuclear Fusion 08/2011; 51(9):094024. · 4.09 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We demonstrate indirect-drive implosion symmetry tuning in a vacuum hohlraum 6.6 mm in length and 3.56 mm in diameter with a CH capsule 6.38 μm in thickness and 1414 μm in diameter, scaled roughly 0.7 × from a National ignition facility (NIF) [E. Moses and C. R. Wuest, Fusion Sci. Technol. 47, 314 (2005)] The hohlraums have radiation drives of 117 ± 4 eV relevant to conditions for the first ∼1 ns of ignition experiments. By varying the relative ratio of the energy between inner and outer beam cones illuminating the hohlraum at OMEGA [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. the shape of the x-ray self-emission, and hence the shape of the emitting object, can be tuned from prolate to oblate. The second-order Legendre coefficient, used to characterize the shape, changes from a negative to a positive value at the time of peak x-ray emission during the implosion through the variation of the cone power balance. With the appropriate selection of the cone power balance, the implosion can be tuned to produce a spherical implosion. Using capsules with thicker walls, this technique can be extended to measure the drive symmetry at later times as the length of the drive pulse is increased [N. M. Hoffman et al., J. Phys.: Conf. Ser. 112, 022075 (2008); N. M. Hoffman et al., Phys. Plasmas 3, 2022 (1996)].
Physics of Plasmas 07/2011; 18(7):072703-072703-6. · 2.15 Impact Factor
-
R. P. J. Town,
M. D. Rosen,
P. A. Michel,
L. Divol,
J. D. Moody,
G. A. Kyrala,
M. B. Schneider, J. L. Kline,
C. A. Thomas,
J. L. Milovich, [......],
S. W. Haan,
J. D. Lindl,
E. L. Dewald,
S. Dixit,
S. H. Glenzer,
O. L. Landen,
E. I. Moses,
H. A. Scott,
J. A. Harte,
G. B. Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: A series of 40 experiments on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)] to study energy balance and implosion symmetry in reduced- and full-scale ignition hohlraums was shot at energies up to 1.3 MJ. This paper reports the findings of the analysis of the ensemble of experimental data obtained that has produced an improved model for simulating ignition hohlraums. Last year the first observation in a NIF hohlraum of energy transfer between cones of beams as a function of wavelength shift between those cones was reported [P. Michel et al., Phys. Plasmas 17, 056305 (2010)]. Detailed analysis of hohlraum wall emission as measured through the laser entrance hole (LEH) has allowed the amount of energy transferred versus wavelength shift to be quantified. The change in outer beam brightness is found to be quantitatively consistent with LASNEX [G. B. Zimmerman and W. L. Kruer, Comments Plasma Phys. Controlled Fusion 2, 51 (1975)] simulations using the predicted energy transfer when possible saturation of the plasma wave mediating the transfer is included. The effect of the predicted energy transfer on implosion symmetry is also found to be in good agreement with gated x-ray framing camera images. Hohlraum energy balance, as measured by x-ray power escaping the LEH, is quantitatively consistent with revised estimates of backscatter and incident laser energy combined with a more rigorous non-local-thermodynamic-equilibrium atomic physics model with greater emissivity than the simpler average-atom model used in the original design of NIF targets.
Physics of Plasmas 04/2011; 18(5):056302-056302-8. · 2.15 Impact Factor
-
P Michel,
L Divol,
R P J Town,
M D Rosen,
D A Callahan,
N B Meezan,
M B Schneider,
G A Kyrala,
J D Moody,
E L Dewald, [......],
D E Hinkel,
R L Berger,
O L Landen,
M J Edwards,
B J MacGowan,
J D Lindl,
C Haynam,
L J Suter,
S H Glenzer,
E Moses
[show abstract]
[hide abstract]
ABSTRACT: By using three tunable wavelengths on different cones of laser beams on the National Ignition Facility, numerical simulations show that the energy transfer between beams can be tuned to redistribute the energy within the cones of beams most prone to backscatter instabilities. These radiative hydrodynamics and laser-plasma interaction simulations have been tested against large-scale hohlraum experiments with two tunable wavelengths and reproduce the hohlraum energetics and symmetry. Using a third wavelength provides a greater level of control of the laser energy distribution and coupling in the hohlraum, and could significantly reduce stimulated Raman scattering losses and increase the hohlraum radiation drive while maintaining a good implosion symmetry.
Physical Review E 04/2011; 83(4 Pt 2):046409. · 2.26 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The influence of binary Coulomb collisions on trapped particle nonlinearities related to stimulated Raman scatter (SRS) in a single laser speckle is examined using one-dimensional particle-in-cell simulations. Binary Coulomb collisions are incorporated using a numerical particle-pairing algorithm that reproduces a collision integral of the Landau form. The onset of nonlinearly enhanced levels of SRS reflectivity is shown to coincide with electron trapping in the daughter plasma wave and is sensitive to the collisional scattering rate. Relaxation of trapping-induced perturbations to the electron velocity distribution via collisional velocity space diffusion is predicted to have the largest effect on the onset of SRS when the amplitude of the daughter plasma wave is smallest, and trapping-induced perturbations to the electron velocity distribution function are also small. In the absence of higher dimensional detrapping mechanisms (e.g., electron side-loss), it is shown that the onset threshold for enhanced SRS reflectivity is determined predominantly by the parallel diffusion of trapped electrons scattering from bulk thermal electrons, and that for the conditions studied here, the contribution to detrapping from perpendicular diffusion is non-negligible. Additionally, inverse bremsstrahlung heating of the bulk electrons is shown to shift the daughter plasma wave spectrum upward along the Stoke’s resonance to larger wave frequency and smaller wave number, changing the linear parametric coupling conditions to SRS backscatter as a function of time. The reduction in SRS reflectivity from binary Coulomb collisions is greatest for laser intensities near the collisionless onset threshold, ulimately leading to an increase in the onset threshold laser intensity for enhanced SRS reflectivity in the kinetic regime.
Physics of Plasmas 03/2011; 18(3):032707-032707-12. · 2.15 Impact Factor
-
J L Kline,
S H Glenzer,
R E Olson,
L J Suter,
K Widmann,
D A Callahan,
S N Dixit,
C A Thomas,
D E Hinkel,
E A Williams, [......],
N B Meezan,
P Michel,
J Moody,
M D Rosen,
M B Schneider,
B Van Wonterghem,
R J Wallace,
B K Young,
O L Landen,
B J MacGowan
[show abstract]
[hide abstract]
ABSTRACT: The first soft x-ray radiation flux measurements from hohlraums using both a 96 and a 192 beam configuration at the National Ignition Facility have shown high x-ray conversion efficiencies of ∼85%-90%. These experiments employed gold vacuum hohlraums, 6.4 mm long and 3.55 mm in diameter, heated with laser energies between 150-635 kJ. The hohlraums reached radiation temperatures of up to 340 eV. These hohlraums for the first time reached coronal plasma conditions sufficient for two-electron processes and coronal heat conduction to be important for determining the radiation drive.
Physical Review Letters 02/2011; 106(8):085003. · 7.37 Impact Factor
-
S H Glenzer,
B J MacGowan,
N B Meezan,
P A Adams,
J B Alfonso,
E T Alger,
Z Alherz,
L F Alvarez,
S S Alvarez,
P V Amick, [......],
H Zhang,
J S Zielinski, J L Kline,
G A Kyrala,
C Niemann,
J D Kilkenny,
A Nikroo,
B M Van Wonterghem,
L J Atherton,
E I Moses
[show abstract]
[hide abstract]
ABSTRACT: We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.
Physical Review Letters 02/2011; 106(8):085004. · 7.37 Impact Factor
