skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Performance of beryllium targets with full-scale capsules in low-fill 6.72-mm hohlraums on the National Ignition Facility

Abstract

When used with 1.06-mm beryllium (Be) capsules on the National Ignition Facility, gold hohlraums with the inner diameter of 5.75 mm and helium gas fill density of 1.6 mg/cm 3 exhibit significant drive degradation due to laser energy backscatter (of order 14%–17%) and “missing” X-ray drive energy (about 32% during the main pulse). Also, hard to simulate cross-beam energy transfer (CBET) must be used to control the implosion symmetry. Larger, 6.72-mm hohlraums with fill densities ≤0.6 mg/cm 3 generally offer improved drive efficiency, reduced hot-electron preheat, and better control of the implosion symmetry without CBET. Recently, we carried out an exploratory campaign to evaluate performance of 1.06-mm Be capsules in such hohlraums and determine optimal hohlraum parameters. Specifically, we performed in this paper a hohlraum fill-density scan with a three-shock, 9.5-ns laser pulse and found that an appropriate axial laser repointing and azimuthal outer-quad splitting resulted in significantly improved hohlraum energetics at fill densities ≤0.3 mg/cm 3 (with backscattered and “missing” energies being of about 5% and 23% of the total laser energy, respectively). The capsule shape at stagnation was slightly oblate and improved with lowering the fill density. We also performed an implosion with a lower-picket, 12.6-ns pulse atmore » the hohlraum fill density of 0.15 mg/cm 3 to observe comparable hohlraum energetics (about 3% of backscattered and 27% of “missing” energy) but an even more oblate implosion shape. Finally, achieving symmetric implosions of 1.06-mm Be capsules in low-fill, 6.72-mm gold hohlraums with reasonably low-adiabat pulses may not be feasible. However, symmetric implosions have recently been successfully demonstrated in such hohlraums with 0.8-mm Be capsules.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1];  [1];  [1];  [1]; ORCiD logo [1];  [2];  [2];  [2]; ORCiD logo [2]; ORCiD logo [2];  [2];  [2];  [2];  [2]; ORCiD logo [2]; ORCiD logo [2];  [2];  [2] more »; ORCiD logo [2];  [2];  [2];  [2];  [2];  [2];  [2];  [2];  [3];  [3];  [3];  [3]; ORCiD logo [3];  [3];  [3];  [4] « less
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. General Atomics, San Diego, CA (United States)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
Contributing Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
OSTI Identifier:
1357132
Alternate Identifier(s):
OSTI ID: 1361879; OSTI ID: 1374518
Report Number(s):
LA-UR-17-20756; LLNL-JRNL-734711
Journal ID: ISSN 1070-664X
Grant/Contract Number:  
AC52-06NA25396; AC52-07NA27344; NA0001808
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Hohlraum; X-ray imaging; Radiosurgery; Stimulated Brillouin scattering; Implosion symmetry

Citation Formats

Simakov, A. N., Wilson, D. C., Yi, S. A., Loomis, E. N., Kline, J. L., Kyrala, G. A., Zylstra, A. B., Dewald, E. L., Tommasini, R., Ralph, J. E., Strozzi, D. J., MacPhee, A. G., Milovich, J. L., Rygg, J. R., Khan, S. F., Ma, T., Jarrott, L. C., Haan, S. W., Celliers, P. M., Marinak, M. M., Rinderknecht, H. G., Robey, H. F., Salmonson, J. D., Stadermann, M., Baxamusa, S., Alford, C., Wang, Y., Nikroo, A., Rice, N., Kong, C., Jaquez, J., Mauldin, M., Youngblood, K. P., Xu, H., Huang, H., and Sio, H.. Performance of beryllium targets with full-scale capsules in low-fill 6.72-mm hohlraums on the National Ignition Facility. United States: N. p., 2017. Web. doi:10.1063/1.4983141.
Simakov, A. N., Wilson, D. C., Yi, S. A., Loomis, E. N., Kline, J. L., Kyrala, G. A., Zylstra, A. B., Dewald, E. L., Tommasini, R., Ralph, J. E., Strozzi, D. J., MacPhee, A. G., Milovich, J. L., Rygg, J. R., Khan, S. F., Ma, T., Jarrott, L. C., Haan, S. W., Celliers, P. M., Marinak, M. M., Rinderknecht, H. G., Robey, H. F., Salmonson, J. D., Stadermann, M., Baxamusa, S., Alford, C., Wang, Y., Nikroo, A., Rice, N., Kong, C., Jaquez, J., Mauldin, M., Youngblood, K. P., Xu, H., Huang, H., & Sio, H.. Performance of beryllium targets with full-scale capsules in low-fill 6.72-mm hohlraums on the National Ignition Facility. United States. doi:10.1063/1.4983141.
Simakov, A. N., Wilson, D. C., Yi, S. A., Loomis, E. N., Kline, J. L., Kyrala, G. A., Zylstra, A. B., Dewald, E. L., Tommasini, R., Ralph, J. E., Strozzi, D. J., MacPhee, A. G., Milovich, J. L., Rygg, J. R., Khan, S. F., Ma, T., Jarrott, L. C., Haan, S. W., Celliers, P. M., Marinak, M. M., Rinderknecht, H. G., Robey, H. F., Salmonson, J. D., Stadermann, M., Baxamusa, S., Alford, C., Wang, Y., Nikroo, A., Rice, N., Kong, C., Jaquez, J., Mauldin, M., Youngblood, K. P., Xu, H., Huang, H., and Sio, H.. Wed . "Performance of beryllium targets with full-scale capsules in low-fill 6.72-mm hohlraums on the National Ignition Facility". United States. doi:10.1063/1.4983141. https://www.osti.gov/servlets/purl/1357132.
@article{osti_1357132,
title = {Performance of beryllium targets with full-scale capsules in low-fill 6.72-mm hohlraums on the National Ignition Facility},
author = {Simakov, A. N. and Wilson, D. C. and Yi, S. A. and Loomis, E. N. and Kline, J. L. and Kyrala, G. A. and Zylstra, A. B. and Dewald, E. L. and Tommasini, R. and Ralph, J. E. and Strozzi, D. J. and MacPhee, A. G. and Milovich, J. L. and Rygg, J. R. and Khan, S. F. and Ma, T. and Jarrott, L. C. and Haan, S. W. and Celliers, P. M. and Marinak, M. M. and Rinderknecht, H. G. and Robey, H. F. and Salmonson, J. D. and Stadermann, M. and Baxamusa, S. and Alford, C. and Wang, Y. and Nikroo, A. and Rice, N. and Kong, C. and Jaquez, J. and Mauldin, M. and Youngblood, K. P. and Xu, H. and Huang, H. and Sio, H.},
abstractNote = {When used with 1.06-mm beryllium (Be) capsules on the National Ignition Facility, gold hohlraums with the inner diameter of 5.75 mm and helium gas fill density of 1.6 mg/cm3 exhibit significant drive degradation due to laser energy backscatter (of order 14%–17%) and “missing” X-ray drive energy (about 32% during the main pulse). Also, hard to simulate cross-beam energy transfer (CBET) must be used to control the implosion symmetry. Larger, 6.72-mm hohlraums with fill densities ≤0.6 mg/cm3 generally offer improved drive efficiency, reduced hot-electron preheat, and better control of the implosion symmetry without CBET. Recently, we carried out an exploratory campaign to evaluate performance of 1.06-mm Be capsules in such hohlraums and determine optimal hohlraum parameters. Specifically, we performed in this paper a hohlraum fill-density scan with a three-shock, 9.5-ns laser pulse and found that an appropriate axial laser repointing and azimuthal outer-quad splitting resulted in significantly improved hohlraum energetics at fill densities ≤0.3 mg/cm3 (with backscattered and “missing” energies being of about 5% and 23% of the total laser energy, respectively). The capsule shape at stagnation was slightly oblate and improved with lowering the fill density. We also performed an implosion with a lower-picket, 12.6-ns pulse at the hohlraum fill density of 0.15 mg/cm3 to observe comparable hohlraum energetics (about 3% of backscattered and 27% of “missing” energy) but an even more oblate implosion shape. Finally, achieving symmetric implosions of 1.06-mm Be capsules in low-fill, 6.72-mm gold hohlraums with reasonably low-adiabat pulses may not be feasible. However, symmetric implosions have recently been successfully demonstrated in such hohlraums with 0.8-mm Be capsules.},
doi = {10.1063/1.4983141},
journal = {Physics of Plasmas},
number = 5,
volume = 24,
place = {United States},
year = {Wed May 10 00:00:00 EDT 2017},
month = {Wed May 10 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 1 work
Citation information provided by
Web of Science

Save / Share: