Implosion shape control of high-velocity, large case-to-capsule ratio beryllium ablators at the National Ignition Facility
Abstract
Experiments at the National Ignition Facility (NIF) show that the implosion shape of inertial confinement fusion ablators is a key factor limiting performance. To achieve more predictable, shape tunable implosions, we have designed and fielded a large 4.2 case-to-capsule ratio target at the NIF using 6.72 mm diameter Au hohlraums and 1.6 mm diameter Cu-doped Be capsules. Simulations show that at these dimensions during a 10 ns 3-shock laser pulse reaching 275 eV hohlraum temperatures, the plasma flow from the hohlraum wall and ablator is not significant enough to impede beam propagation. Experiments measuring the shock symmetry and in-flight shell symmetry closely matched the simulations. Most notably, in two experiments, we demonstrated symmetry control from negative to positive Legendre P2 space by varying the inner to total laser power cone fraction by 5% below and above the predicted symmetric value. In conclusion, some discrepancies found in 1st shock arrival times that could affect agreement in late time implosion symmetry suggest hohlraum and capsule modeling uncertainties do remain, but this target design reduces sensitivities to them.
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- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Rochester, NY (United States). Lab. for Laser Energetics
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- General Atomics, San Diego, CA (United States)
- Publication Date:
- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1463550
- Alternate Identifier(s):
- OSTI ID: 1461928
- Report Number(s):
- LA-UR-17-29075
Journal ID: ISSN 1070-664X; TRN: US1902315
- Grant/Contract Number:
- AC52-06NA25396
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Physics of Plasmas
- Additional Journal Information:
- Journal Volume: 25; Journal Issue: 7; 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
Citation Formats
Loomis, E. N., Yi, Sunghwan A., Kyrala, George Amine, Kline, John L., Simakov, Andrei N., Ralph, Joseph, Millot, Marius, Dewald, Edouard, Zylstra, Alex, Rygg, J. R., Celliers, P., Goyon, C., Lahmann, B., Sio, H., MacLaren, Stephen, Masse, Laurent, Callahan, Debra, Hurricane, Omar, Wilson, Douglas Carl, Rice, Neal, Huang, Haibo, Kong, C., Bae, J., Nikroo, Abbas, and Batha, Steven H. Implosion shape control of high-velocity, large case-to-capsule ratio beryllium ablators at the National Ignition Facility. United States: N. p., 2018.
Web. doi:10.1063/1.5040995.
Loomis, E. N., Yi, Sunghwan A., Kyrala, George Amine, Kline, John L., Simakov, Andrei N., Ralph, Joseph, Millot, Marius, Dewald, Edouard, Zylstra, Alex, Rygg, J. R., Celliers, P., Goyon, C., Lahmann, B., Sio, H., MacLaren, Stephen, Masse, Laurent, Callahan, Debra, Hurricane, Omar, Wilson, Douglas Carl, Rice, Neal, Huang, Haibo, Kong, C., Bae, J., Nikroo, Abbas, & Batha, Steven H. Implosion shape control of high-velocity, large case-to-capsule ratio beryllium ablators at the National Ignition Facility. United States. doi:10.1063/1.5040995.
Loomis, E. N., Yi, Sunghwan A., Kyrala, George Amine, Kline, John L., Simakov, Andrei N., Ralph, Joseph, Millot, Marius, Dewald, Edouard, Zylstra, Alex, Rygg, J. R., Celliers, P., Goyon, C., Lahmann, B., Sio, H., MacLaren, Stephen, Masse, Laurent, Callahan, Debra, Hurricane, Omar, Wilson, Douglas Carl, Rice, Neal, Huang, Haibo, Kong, C., Bae, J., Nikroo, Abbas, and Batha, Steven H. Sun .
"Implosion shape control of high-velocity, large case-to-capsule ratio beryllium ablators at the National Ignition Facility". United States. doi:10.1063/1.5040995. https://www.osti.gov/servlets/purl/1463550.
@article{osti_1463550,
title = {Implosion shape control of high-velocity, large case-to-capsule ratio beryllium ablators at the National Ignition Facility},
author = {Loomis, E. N. and Yi, Sunghwan A. and Kyrala, George Amine and Kline, John L. and Simakov, Andrei N. and Ralph, Joseph and Millot, Marius and Dewald, Edouard and Zylstra, Alex and Rygg, J. R. and Celliers, P. and Goyon, C. and Lahmann, B. and Sio, H. and MacLaren, Stephen and Masse, Laurent and Callahan, Debra and Hurricane, Omar and Wilson, Douglas Carl and Rice, Neal and Huang, Haibo and Kong, C. and Bae, J. and Nikroo, Abbas and Batha, Steven H.},
abstractNote = {Experiments at the National Ignition Facility (NIF) show that the implosion shape of inertial confinement fusion ablators is a key factor limiting performance. To achieve more predictable, shape tunable implosions, we have designed and fielded a large 4.2 case-to-capsule ratio target at the NIF using 6.72 mm diameter Au hohlraums and 1.6 mm diameter Cu-doped Be capsules. Simulations show that at these dimensions during a 10 ns 3-shock laser pulse reaching 275 eV hohlraum temperatures, the plasma flow from the hohlraum wall and ablator is not significant enough to impede beam propagation. Experiments measuring the shock symmetry and in-flight shell symmetry closely matched the simulations. Most notably, in two experiments, we demonstrated symmetry control from negative to positive Legendre P2 space by varying the inner to total laser power cone fraction by 5% below and above the predicted symmetric value. In conclusion, some discrepancies found in 1st shock arrival times that could affect agreement in late time implosion symmetry suggest hohlraum and capsule modeling uncertainties do remain, but this target design reduces sensitivities to them.},
doi = {10.1063/1.5040995},
journal = {Physics of Plasmas},
number = 7,
volume = 25,
place = {United States},
year = {2018},
month = {7}
}
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