Neutron yield study of direct-drive, low-adiabat cryogenic D2 implosions on OMEGA laser system

S. X. Hu; P. B. Radha; J. A. Marozas; R. Betti; T. J.B. Collins; R. S. Craxton; J. A. Delettrez; D. H. Edgell; R. Epstein; V. N. Goncharov; I. V. Igumenshchev; F. J. Marshall; R. L. McCrory; D. D. Meyerhofer; S. P. Regan; T. C. Sangster; S. Skupsky; V. A. Smalyuk; Y. Elbaz; D. Shvarts

doi:10.1063/1.3259355

Neutron yield study of direct-drive, low-adiabat cryogenic D₂ implosions on OMEGA laser system

S. X. Hu, P. B. Radha, J. A. Marozas, R. Betti, T. J.B. Collins, R. S. Craxton, J. A. Delettrez, D. H. Edgell, R. Epstein, V. N. Goncharov, I. V. Igumenshchev, F. J. Marshall, R. L. McCrory, D. D. Meyerhofer, S. P. Regan, T. C. Sangster, S. Skupsky, V. A. Smalyuk, Y. Elbaz, D. Shvarts

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Abstract

Neutron yields of direct-drive, low-adiabat (α≈2 to 3) cryogenic D² target implosions on the OMEGA laser system [T. R. Boehly, Opt. Commun. 133, 495 (1997)] have been systematically investigated using the two-dimensional (2D) radiation hydrodynamics code DRACO [P. B. Radha, Phys. Plasmas 12, 056307 (2005)]. Low-mode (ℓ≤12) perturbations, including initial target offset, ice-layer roughness, and laser-beam power imbalance, were found to be the primary source of yield reduction for thin-shell (5 μm), low-α, cryogenic targets. The 2D simulations of thin-shell implosions track experimental measurements for different target conditions and peak laser intensities ranging from 2.5 × 10¹⁴ -6 × 10¹⁴ W/cm². Simulations indicate that the fusion yield is sensitive to the relative phases between the target offset and the ice-layer perturbations. The results provide a reasonable good guide to understanding the yield degradation in direct-drive, low-adiabat, cryogenic, thin-shell-target implosions. Thick-shell (10 μm) implosions generally give lower yield over clean than low-ℓ-mode DRACO simulation predictions. Simulations including the effect of laser-beam nonuniformities indicate that high-ℓ-mode perturbations caused by laser imprinting further degrade the neutron yield of thick-shell implosions. To study ICF compression physics, these results suggest a target specification with a ≤30 μm offset and ice-roughness of σ_rms <3 μm are required.

Original language	English
Article number	112706
Pages (from-to)	112706
Number of pages	1
Journal	Physics of Plasmas
Volume	16
Issue number	11
DOIs	https://doi.org/10.1063/1.3259355
State	Published - 16 Dec 2009
Externally published	Yes

ASJC Scopus subject areas

Condensed Matter Physics

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10.1063/1.3259355

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Hu, S. X., Radha, P. B., Marozas, J. A., Betti, R., Collins, T. J. B., Craxton, R. S., Delettrez, J. A., Edgell, D. H., Epstein, R., Goncharov, V. N., Igumenshchev, I. V., Marshall, F. J., McCrory, R. L., Meyerhofer, D. D., Regan, S. P., Sangster, T. C., Skupsky, S., Smalyuk, V. A., Elbaz, Y., & Shvarts, D. (2009). Neutron yield study of direct-drive, low-adiabat cryogenic D₂ implosions on OMEGA laser system. Physics of Plasmas, 16(11), 112706. Article 112706. https://doi.org/10.1063/1.3259355

@article{ee4b11f3638741ed94b30325974d0e40,

title = "Neutron yield study of direct-drive, low-adiabat cryogenic D2 implosions on OMEGA laser system",

abstract = "Neutron yields of direct-drive, low-adiabat (α≈2 to 3) cryogenic D2 target implosions on the OMEGA laser system [T. R. Boehly, Opt. Commun. 133, 495 (1997)] have been systematically investigated using the two-dimensional (2D) radiation hydrodynamics code DRACO [P. B. Radha, Phys. Plasmas 12, 056307 (2005)]. Low-mode (ℓ≤12) perturbations, including initial target offset, ice-layer roughness, and laser-beam power imbalance, were found to be the primary source of yield reduction for thin-shell (5 μm), low-α, cryogenic targets. The 2D simulations of thin-shell implosions track experimental measurements for different target conditions and peak laser intensities ranging from 2.5 × 1014 -6 × 1014 W/cm2. Simulations indicate that the fusion yield is sensitive to the relative phases between the target offset and the ice-layer perturbations. The results provide a reasonable good guide to understanding the yield degradation in direct-drive, low-adiabat, cryogenic, thin-shell-target implosions. Thick-shell (10 μm) implosions generally give lower yield over clean than low-ℓ-mode DRACO simulation predictions. Simulations including the effect of laser-beam nonuniformities indicate that high-ℓ-mode perturbations caused by laser imprinting further degrade the neutron yield of thick-shell implosions. To study ICF compression physics, these results suggest a target specification with a ≤30 μm offset and ice-roughness of σrms <3 μm are required.",

author = "Hu, {S. X.} and Radha, {P. B.} and Marozas, {J. A.} and R. Betti and Collins, {T. J.B.} and Craxton, {R. S.} and Delettrez, {J. A.} and Edgell, {D. H.} and R. Epstein and Goncharov, {V. N.} and Igumenshchev, {I. V.} and Marshall, {F. J.} and McCrory, {R. L.} and Meyerhofer, {D. D.} and Regan, {S. P.} and Sangster, {T. C.} and S. Skupsky and Smalyuk, {V. A.} and Y. Elbaz and D. Shvarts",

note = "Funding Information: This work was supported by the U.S. Department of Energy (DOE) Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302, the University of Rochester, and the New York State Energy Research and Development Authority.",

year = "2009",

month = dec,

day = "16",

doi = "10.1063/1.3259355",

language = "English",

volume = "16",

pages = "112706",

journal = "Physics of Plasmas",

issn = "1070-664X",

publisher = "American Institute of Physics",

number = "11",

}

Hu, SX, Radha, PB, Marozas, JA, Betti, R, Collins, TJB, Craxton, RS, Delettrez, JA, Edgell, DH, Epstein, R, Goncharov, VN, Igumenshchev, IV, Marshall, FJ, McCrory, RL, Meyerhofer, DD, Regan, SP, Sangster, TC, Skupsky, S, Smalyuk, VA, Elbaz, Y & Shvarts, D 2009, 'Neutron yield study of direct-drive, low-adiabat cryogenic D₂ implosions on OMEGA laser system', Physics of Plasmas, vol. 16, no. 11, 112706, pp. 112706. https://doi.org/10.1063/1.3259355

TY - JOUR

T1 - Neutron yield study of direct-drive, low-adiabat cryogenic D2 implosions on OMEGA laser system

AU - Hu, S. X.

AU - Radha, P. B.

AU - Marozas, J. A.

AU - Betti, R.

AU - Collins, T. J.B.

AU - Craxton, R. S.

AU - Delettrez, J. A.

AU - Edgell, D. H.

AU - Epstein, R.

AU - Goncharov, V. N.

AU - Igumenshchev, I. V.

AU - Marshall, F. J.

AU - McCrory, R. L.

AU - Meyerhofer, D. D.

AU - Regan, S. P.

AU - Sangster, T. C.

AU - Skupsky, S.

AU - Smalyuk, V. A.

AU - Elbaz, Y.

AU - Shvarts, D.

N1 - Funding Information: This work was supported by the U.S. Department of Energy (DOE) Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302, the University of Rochester, and the New York State Energy Research and Development Authority.

PY - 2009/12/16

Y1 - 2009/12/16

N2 - Neutron yields of direct-drive, low-adiabat (α≈2 to 3) cryogenic D2 target implosions on the OMEGA laser system [T. R. Boehly, Opt. Commun. 133, 495 (1997)] have been systematically investigated using the two-dimensional (2D) radiation hydrodynamics code DRACO [P. B. Radha, Phys. Plasmas 12, 056307 (2005)]. Low-mode (ℓ≤12) perturbations, including initial target offset, ice-layer roughness, and laser-beam power imbalance, were found to be the primary source of yield reduction for thin-shell (5 μm), low-α, cryogenic targets. The 2D simulations of thin-shell implosions track experimental measurements for different target conditions and peak laser intensities ranging from 2.5 × 1014 -6 × 1014 W/cm2. Simulations indicate that the fusion yield is sensitive to the relative phases between the target offset and the ice-layer perturbations. The results provide a reasonable good guide to understanding the yield degradation in direct-drive, low-adiabat, cryogenic, thin-shell-target implosions. Thick-shell (10 μm) implosions generally give lower yield over clean than low-ℓ-mode DRACO simulation predictions. Simulations including the effect of laser-beam nonuniformities indicate that high-ℓ-mode perturbations caused by laser imprinting further degrade the neutron yield of thick-shell implosions. To study ICF compression physics, these results suggest a target specification with a ≤30 μm offset and ice-roughness of σrms <3 μm are required.

AB - Neutron yields of direct-drive, low-adiabat (α≈2 to 3) cryogenic D2 target implosions on the OMEGA laser system [T. R. Boehly, Opt. Commun. 133, 495 (1997)] have been systematically investigated using the two-dimensional (2D) radiation hydrodynamics code DRACO [P. B. Radha, Phys. Plasmas 12, 056307 (2005)]. Low-mode (ℓ≤12) perturbations, including initial target offset, ice-layer roughness, and laser-beam power imbalance, were found to be the primary source of yield reduction for thin-shell (5 μm), low-α, cryogenic targets. The 2D simulations of thin-shell implosions track experimental measurements for different target conditions and peak laser intensities ranging from 2.5 × 1014 -6 × 1014 W/cm2. Simulations indicate that the fusion yield is sensitive to the relative phases between the target offset and the ice-layer perturbations. The results provide a reasonable good guide to understanding the yield degradation in direct-drive, low-adiabat, cryogenic, thin-shell-target implosions. Thick-shell (10 μm) implosions generally give lower yield over clean than low-ℓ-mode DRACO simulation predictions. Simulations including the effect of laser-beam nonuniformities indicate that high-ℓ-mode perturbations caused by laser imprinting further degrade the neutron yield of thick-shell implosions. To study ICF compression physics, these results suggest a target specification with a ≤30 μm offset and ice-roughness of σrms <3 μm are required.

UR - http://www.scopus.com/inward/record.url?scp=71749113409&partnerID=8YFLogxK

U2 - 10.1063/1.3259355

DO - 10.1063/1.3259355

M3 - Article

AN - SCOPUS:71749113409

SN - 1070-664X

VL - 16

SP - 112706

JO - Physics of Plasmas

JF - Physics of Plasmas

IS - 11

M1 - 112706

ER -

Neutron yield study of direct-drive, low-adiabat cryogenic D₂ implosions on OMEGA laser system

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