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Progress towards a more predictive model for hohlraum radiation drive and symmetry

For several years, we have been calculating the radiation drive in laser-heated gold hohlraums using flux-limited heat transport with a limiter of 0.15, tabulated values of local thermodynamic equilibrium gold opacity, and an approximate model for not in a local thermodynamic equilibrium (NLTE) gold...

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Autores principales: Jones, O. S., Suter, L. J., Scott, H. A., Barrios, M. A., Farmer, W. A., Hansen, S. B., Liedahl, D. A., Mauche, C. W., Moore, A. S., Rosen, M. D., Salmonson, J. D., Strozzi, D. J., Thomas, C. A., Turnbull, D. P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438280/
https://www.ncbi.nlm.nih.gov/pubmed/28611532
http://dx.doi.org/10.1063/1.4982693
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author Jones, O. S.
Suter, L. J.
Scott, H. A.
Barrios, M. A.
Farmer, W. A.
Hansen, S. B.
Liedahl, D. A.
Mauche, C. W.
Moore, A. S.
Rosen, M. D.
Salmonson, J. D.
Strozzi, D. J.
Thomas, C. A.
Turnbull, D. P.
author_facet Jones, O. S.
Suter, L. J.
Scott, H. A.
Barrios, M. A.
Farmer, W. A.
Hansen, S. B.
Liedahl, D. A.
Mauche, C. W.
Moore, A. S.
Rosen, M. D.
Salmonson, J. D.
Strozzi, D. J.
Thomas, C. A.
Turnbull, D. P.
author_sort Jones, O. S.
collection PubMed
description For several years, we have been calculating the radiation drive in laser-heated gold hohlraums using flux-limited heat transport with a limiter of 0.15, tabulated values of local thermodynamic equilibrium gold opacity, and an approximate model for not in a local thermodynamic equilibrium (NLTE) gold emissivity (DCA_2010). This model has been successful in predicting the radiation drive in vacuum hohlraums, but for gas-filled hohlraums used to drive capsule implosions, the model consistently predicts too much drive and capsule bang times earlier than measured. In this work, we introduce a new model that brings the calculated bang time into better agreement with the measured bang time. The new model employs (1) a numerical grid that is fully converged in space, energy, and time, (2) a modified approximate NLTE model that includes more physics and is in better agreement with more detailed offline emissivity models, and (3) a reduced flux limiter value of 0.03. We applied this model to gas-filled hohlraum experiments using high density carbon and plastic ablator capsules that had hohlraum He fill gas densities ranging from 0.06 to 1.6 mg/cc and hohlraum diameters of 5.75 or 6.72 mm. The new model predicts bang times to within ±100 ps for most experiments with low to intermediate fill densities (up to 0.85 mg/cc). This model predicts higher temperatures in the plasma than the old model and also predicts that at higher gas fill densities, a significant amount of inner beam laser energy escapes the hohlraum through the opposite laser entrance hole.
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spelling pubmed-54382802017-06-13 Progress towards a more predictive model for hohlraum radiation drive and symmetry Jones, O. S. Suter, L. J. Scott, H. A. Barrios, M. A. Farmer, W. A. Hansen, S. B. Liedahl, D. A. Mauche, C. W. Moore, A. S. Rosen, M. D. Salmonson, J. D. Strozzi, D. J. Thomas, C. A. Turnbull, D. P. Phys Plasmas INVITED PAPERS For several years, we have been calculating the radiation drive in laser-heated gold hohlraums using flux-limited heat transport with a limiter of 0.15, tabulated values of local thermodynamic equilibrium gold opacity, and an approximate model for not in a local thermodynamic equilibrium (NLTE) gold emissivity (DCA_2010). This model has been successful in predicting the radiation drive in vacuum hohlraums, but for gas-filled hohlraums used to drive capsule implosions, the model consistently predicts too much drive and capsule bang times earlier than measured. In this work, we introduce a new model that brings the calculated bang time into better agreement with the measured bang time. The new model employs (1) a numerical grid that is fully converged in space, energy, and time, (2) a modified approximate NLTE model that includes more physics and is in better agreement with more detailed offline emissivity models, and (3) a reduced flux limiter value of 0.03. We applied this model to gas-filled hohlraum experiments using high density carbon and plastic ablator capsules that had hohlraum He fill gas densities ranging from 0.06 to 1.6 mg/cc and hohlraum diameters of 5.75 or 6.72 mm. The new model predicts bang times to within ±100 ps for most experiments with low to intermediate fill densities (up to 0.85 mg/cc). This model predicts higher temperatures in the plasma than the old model and also predicts that at higher gas fill densities, a significant amount of inner beam laser energy escapes the hohlraum through the opposite laser entrance hole. AIP Publishing LLC 2017-05 2017-05-19 /pmc/articles/PMC5438280/ /pubmed/28611532 http://dx.doi.org/10.1063/1.4982693 Text en © 2017 Author(s). 1070-664X/2017/24(5)/056312/9 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle INVITED PAPERS
Jones, O. S.
Suter, L. J.
Scott, H. A.
Barrios, M. A.
Farmer, W. A.
Hansen, S. B.
Liedahl, D. A.
Mauche, C. W.
Moore, A. S.
Rosen, M. D.
Salmonson, J. D.
Strozzi, D. J.
Thomas, C. A.
Turnbull, D. P.
Progress towards a more predictive model for hohlraum radiation drive and symmetry
title Progress towards a more predictive model for hohlraum radiation drive and symmetry
title_full Progress towards a more predictive model for hohlraum radiation drive and symmetry
title_fullStr Progress towards a more predictive model for hohlraum radiation drive and symmetry
title_full_unstemmed Progress towards a more predictive model for hohlraum radiation drive and symmetry
title_short Progress towards a more predictive model for hohlraum radiation drive and symmetry
title_sort progress towards a more predictive model for hohlraum radiation drive and symmetry
topic INVITED PAPERS
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5438280/
https://www.ncbi.nlm.nih.gov/pubmed/28611532
http://dx.doi.org/10.1063/1.4982693
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