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Ceurvorst L, Theobald W, Rosenberg MJ, Radha PB, Stoeckl C, Betti R, Anderson KS, Marozas JA, Goncharov VN, Campbell EM, Shuldberg CM, Luo RW, Sweet W, Aghaian L, Carlson L, Bachmann B, Döppner T, Hohenberger M, Glize K, Scott RHH, Colaïtis A, Regan SP. Development of an x-ray radiography platform to study laser-direct-drive energy coupling at the National Ignition Facility. Rev Sci Instrum 2022; 93:105102. [PMID: 36319381 DOI: 10.1063/5.0098982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/14/2022] [Indexed: 06/16/2023]
Abstract
A platform has been developed to study laser-direct-drive energy coupling at the National Ignition Facility (NIF) using a plastic sphere target irradiated in a polar-direct-drive geometry to launch a spherically converging shock wave. To diagnose this system evolution, eight NIF laser beams are directed onto a curved Cu foil to generate Heα line emission at a photon energy of 8.4 keV. These x rays are collected by a 100-ps gated x-ray imager in the opposing port to produce temporally gated radiographs. The platform is capable of acquiring images during and after the laser drive launches the shock wave. A backlighter profile is fit to the radiographs, and the resulting transmission images are Abel inverted to infer radial density profiles of the shock front and to track its temporal evolution. The measurements provide experimental shock trajectories and radial density profiles that are compared to 2D radiation-hydrodynamic simulations using cross-beam energy transfer and nonlocal heat-transport models.
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Affiliation(s)
- L Ceurvorst
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - W Theobald
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - M J Rosenberg
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - P B Radha
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - R Betti
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - K S Anderson
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - J A Marozas
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - V N Goncharov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - E M Campbell
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | | | - R W Luo
- General Atomics, San Diego, California 92121, USA
| | - W Sweet
- General Atomics, San Diego, California 92121, USA
| | - L Aghaian
- General Atomics, San Diego, California 92121, USA
| | - L Carlson
- General Atomics, San Diego, California 92121, USA
| | - B Bachmann
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - T Döppner
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M Hohenberger
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - K Glize
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX, United Kingdom
| | - R H H Scott
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Oxfordshire, OX11 0QX, United Kingdom
| | - A Colaïtis
- Centre Lasers Intenses et Applications, CELIA, Université de Bordeaux-CNRS-CEA, UMR 5107, Talence F-33405, France
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
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Hohenberger M, Meezan NB, Riedel WM, Kabadi N, Forrest CJ, Aghaian L, Cappelli MA, Farrell M, Glenzer SH, Heeter B, Heredia R, Landen OL, Mackinnon AJ, Petrasso R, Shuldberg CM, Treffert F, Hsing WW. Developing "inverted-corona" fusion targets as high-fluence neutron sources. Rev Sci Instrum 2021; 92:033544. [PMID: 33819995 DOI: 10.1063/5.0040877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/06/2021] [Indexed: 06/12/2023]
Abstract
We present experimental studies of inverted-corona targets as neutron sources at the OMEGA Laser Facility and the National Ignition Facility (NIF). Laser beams are directed onto the inner walls of a capsule via laser-entrance holes (LEHs), heating the target interior to fusion conditions. The fusion fuel is provided either as a wall liner, e.g., deuterated plastic (CD), or as a gas fill, e.g., D2 gas. Such targets are robust to low-mode drive asymmetries, allowing for single-sided laser drive. On OMEGA, 1.8-mm-diameter targets with either a 10-μm CD liner or up to 2 atm of D2-gas fill were driven with up to 18 kJ of laser energy in a 1-ns square pulse. Neutron yields of up to 1.5 × 1010 generally followed expected trends with fill pressure or laser energy, although the data imply some mix of the CH wall into the fusion fuel for either design. Comparable performance was observed with single-sided (1x LEH) or double-sided (2x LEH) drive. NIF experiments tested the platform at scaled up dimensions and energies, combining a 15-μm CD liner and a 3-atm D2-gas fill in a 4.5-mm diameter target, laser-driven with up to 330 kJ. Neutron yields up to 2.6 × 1012 were measured, exceeding the scaled yield expectation from the OMEGA data. The observed energy scaling on the NIF implies that the neutron production is gas dominated, suggesting a performance boost from using deuterium-tritium (DT) gas. We estimate that neutron yields exceeding 1014 should be readily achievable using a modest laser drive of ∼300 kJ with a DT fill.
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Affiliation(s)
- M Hohenberger
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - N B Meezan
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - W M Riedel
- Stanford University, Stanford, California 94305, USA
| | - N Kabadi
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C J Forrest
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - L Aghaian
- General Atomics, 3550 General Atomics Court, San Diego, California 92121, USA
| | - M A Cappelli
- Stanford University, Stanford, California 94305, USA
| | - M Farrell
- General Atomics, 3550 General Atomics Court, San Diego, California 92121, USA
| | - S H Glenzer
- SLAC National Accelerator Laboratory, Menlo Park, California 94309, USA
| | - B Heeter
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Heredia
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - O L Landen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A J Mackinnon
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Petrasso
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C M Shuldberg
- General Atomics, 3550 General Atomics Court, San Diego, California 92121, USA
| | - F Treffert
- SLAC National Accelerator Laboratory, Menlo Park, California 94309, USA
| | - W W Hsing
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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