Experimental validation of a diagnostic technique for tuning the fourth shock timing on National Ignition Facility

Robey, H. F.; Boehly, T. R.; Olson, R. E.; Nikroo, A.; Celliers, P. M.; Landen, O. L.; Meyerhofer, D. D.

doi:10.1063/1.3276154

Cited by 26 publications

(17 citation statements)

References 14 publications

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“…Results from six previous beryllium shots gave a consistent set of time dependent drive multipliers that were used to tune the calculations. This forced consistent agreement with diagnostics in VISAR, 9 1DconA, 10 and 2DconA 11 implosions, including the time of peak yield rate or bangtime 12 and Dante 13 radiation flux. Other experiments have shown that the radiation flux within the hohlraum is actually depleted, 14 suggesting that erroneous hohlraum physics 15 is being compensated for.…”

Section: Calculated Activationsupporting

confidence: 57%

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

et al. 2017

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For the first time, 41Ar produced by the (n,ϒ) reaction from 40Ar in the beryllium shell of a DT filled Inertial Confinement Fusion capsule has been measured. Ar is co-deposited with beryllium in the sputter deposition of the capsule shell. Combined with a measurement of the neutron yield, the radioactive 41Ar then quantifies the areal density of beryllium during the DT neutron production. The measured 1.15 ± 0.17 × 10+8 atoms of 41Ar are 2.5 times that from the best post-shot calculation, suggesting that the Ar and Be areal densities are correspondingly higher than those calculated. Possible explanations are that (1) the beryllium shell is compressed more than calculated, (2) beryllium has mixed into the cold DT ice, or more likely (3) less beryllium is ablated than calculated. Since only one DT filled beryllium capsule has been fielded at NIF, these results can be confirmed and expanded in the future.

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Section: Calculated Activationsupporting

confidence: 57%

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

et al. 2017

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“…We have found that when we apply the model described above to the shock timing [3] and convergent ablation [4] experiments, it overestimates the shock speeds and shell velocity, and as a result predicts x-ray bangtimes ∼300-700 ps earlier than measured. Thus the simulations have a higher implosion a e-mail: jones96@llnl.gov This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.…”

Section: Introductionmentioning

confidence: 99%

“…The NIC strategy relies on a series of symmetry, shock timing, and ablator experiments to experimentally tune the implosion to the required velocity, symmetry, etc. [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Towards an integrated model of the NIC layered implosions

Jones

Callahan

Cerjan

et al. 2013

EPJ Web of Conferences

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Abstract.A detailed simulation-based model of the June 2011 National Ignition Campaign (NIC) cryogenic DT experiments is presented. The model is based on integrated hohlraum-capsule simulations that utilize the best available models for the hohlraum wall, ablator, and DT equations of state and opacities. The calculated radiation drive was adjusted by changing the input laser power to match the experimentally measured shock speeds, shock merger times, peak implosion velocity, and bangtime. The crossbeam energy transfer model was tuned to match the measured time-dependent symmetry. Mid-mode mix was included by directly modeling the ablator and ice surface perturbations up to mode 60. Simulated experimental values were extracted from the simulation and compared against the experiment. The model adjustments brought much of the simulated data into closer agreement with the experiment, with the notable exception of the measured yields, which were 15-40% of the calculated yields.

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“…The viability of using the VISAR and SOP for this reentrant witness plate shock breakout measurement was successfully tested 21 at OMEGA using the experimental setup shown in Fig. 4͑a͒.…”

Section: Timing Of Fourth Shockmentioning

confidence: 99%

Capsule performance optimization in the National Ignition Campaign

et al. 2010

Self Cite

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A capsule performance optimization campaign will be conducted at the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, 228 (2004)] to substantially increase the probability of ignition by laser-driven hohlraums [J. D. Lindl et al., Phys. Plasmas 11, 339 (2004)]. The campaign will experimentally correct for residual uncertainties in the implosion and hohlraum physics used in our radiation-hydrodynamic computational models before proceeding to cryogenic-layered implosions and ignition attempts. The required tuning techniques using a variety of ignition capsule surrogates have been demonstrated at the OMEGA facility under scaled hohlraum and capsule conditions relevant to the ignition design and shown to meet the required sensitivity and accuracy. In addition, a roll-up of all expected random and systematic uncertainties in setting the key ignition laser and target parameters due to residual measurement, calibration, cross-coupling, surrogacy, and scale-up errors has been derived that meets the required budget.

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Experimental validation of a diagnostic technique for tuning the fourth shock timing on National Ignition Facility

Cited by 26 publications

References 14 publications

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

Use of 41Ar production to measure ablator areal density in NIF beryllium implosions

Towards an integrated model of the NIC layered implosions

Capsule performance optimization in the National Ignition Campaign

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