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Title: Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)]

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 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. 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. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. 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 DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent CH layer, was examined. The inferred amountmore » of hot-spot mix mass, estimated from the Ge K-shell line brightness using a detailed atomic physics code, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.« less

Authors:
 [1];  [1];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [3];  [2];  [2] more »;  [2];  [2];  [4];  [5];  [5];  [2];  [2];  [3];  [6];  [1];  [2];  [1];  [7];  [8];  [9];  [2];  [2] « less
  1. Univ. of Rochester, Rochester, NY (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Prism Computational Sciences, Madison, WI (United States)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); General Atomics, San Diego, CA (United States)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  6. Univ. of Nevada, Reno, NV (United States)
  7. General Atomics, San Diego, CA (United States)
  8. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  9. Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1343041
Report Number(s):
LLNL-JRNL-520491
Journal ID: ISSN 1070-664X
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 19; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION

Citation Formats

Regan, S. P., Epstein, R., Hammel, B. A., Suter, L. J., Ralph, J., Scott, H., Barrios, M. A., Bradley, D. K., Callahan, D. A., Cerjan, C., Collins, G. W., Dixit, S. N., Doeppner, T., Edwards, M. J., Farley, D. R., Glenn, S., Glenzer, S. H., Golovkin, I. E., Haan, S. W., Hamza, A., Hicks, D. G., Izumi, N., Kilkenny, J. D., Kline, J. L., Kyrala, G. A., Landen, O. L., Ma, T., MacFarlane, J. J., Mancini, R. C., McCrory, R. L., Meezan, N. B., Meyerhofer, D. D., Nikroo, A., Peterson, K. J., Sangster, T. C., Springer, P., and Town, R. P. J. Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)]. United States: N. p., 2012. Web. doi:10.1063/1.3694057.
Regan, S. P., Epstein, R., Hammel, B. A., Suter, L. J., Ralph, J., Scott, H., Barrios, M. A., Bradley, D. K., Callahan, D. A., Cerjan, C., Collins, G. W., Dixit, S. N., Doeppner, T., Edwards, M. J., Farley, D. R., Glenn, S., Glenzer, S. H., Golovkin, I. E., Haan, S. W., Hamza, A., Hicks, D. G., Izumi, N., Kilkenny, J. D., Kline, J. L., Kyrala, G. A., Landen, O. L., Ma, T., MacFarlane, J. J., Mancini, R. C., McCrory, R. L., Meezan, N. B., Meyerhofer, D. D., Nikroo, A., Peterson, K. J., Sangster, T. C., Springer, P., & Town, R. P. J. Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)]. United States. doi:10.1063/1.3694057.
Regan, S. P., Epstein, R., Hammel, B. A., Suter, L. J., Ralph, J., Scott, H., Barrios, M. A., Bradley, D. K., Callahan, D. A., Cerjan, C., Collins, G. W., Dixit, S. N., Doeppner, T., Edwards, M. J., Farley, D. R., Glenn, S., Glenzer, S. H., Golovkin, I. E., Haan, S. W., Hamza, A., Hicks, D. G., Izumi, N., Kilkenny, J. D., Kline, J. L., Kyrala, G. A., Landen, O. L., Ma, T., MacFarlane, J. J., Mancini, R. C., McCrory, R. L., Meezan, N. B., Meyerhofer, D. D., Nikroo, A., Peterson, K. J., Sangster, T. C., Springer, P., and Town, R. P. J. Fri . "Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)]". United States. doi:10.1063/1.3694057. https://www.osti.gov/servlets/purl/1343041.
@article{osti_1343041,
title = {Hot-spot mix in ignition-scale implosions on the NIF [Hot-spot mix in ignition-scale implosions on the National Ignition Facility (NIF)]},
author = {Regan, S. P. and Epstein, R. and Hammel, B. A. and Suter, L. J. and Ralph, J. and Scott, H. and Barrios, M. A. and Bradley, D. K. and Callahan, D. A. and Cerjan, C. and Collins, G. W. and Dixit, S. N. and Doeppner, T. and Edwards, M. J. and Farley, D. R. and Glenn, S. and Glenzer, S. H. and Golovkin, I. E. and Haan, S. W. and Hamza, A. and Hicks, D. G. and Izumi, N. and Kilkenny, J. D. and Kline, J. L. and Kyrala, G. A. and Landen, O. L. and Ma, T. and MacFarlane, J. J. and Mancini, R. C. and McCrory, R. L. and Meezan, N. B. and Meyerhofer, D. D. and Nikroo, A. and Peterson, K. J. and Sangster, T. C. and Springer, P. and Town, R. P. J.},
abstractNote = {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 2 a thin shell of cryogenic thermonuclear fuel (i.e., hydrogen isotopes), with fuel vapor filling the interior volume. 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. Richtmyer–Meshkov and Rayleigh–Taylor hydrodynamic instabilities seeded by high-mode (50 < t < 200) ablator-surface perturbations can cause Ge-doped ablator to mix into the interior of the shell at the end of the acceleration phase. 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 DT cryogenic targets and gas-filled plastic shell capsules, which replace the THD layer with a massequivalent 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, is typically below the 75 ng allowance for hot-spot mix. Furthermore, predictions of a simple mix model, based on linear growth of the measured surface-mass modulations, are consistent with the experimental results.},
doi = {10.1063/1.3694057},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 19,
place = {United States},
year = {2012},
month = {3}
}

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