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Ruyer C, Fusaro A, Debayle A, Capdessus R, Loiseau P, Masson-Laborde PE. Influence of a random phase plate on the growth of the backward stimulated Brillouin scatter. Phys Rev E 2023; 107:035208. [PMID: 37073038 DOI: 10.1103/physreve.107.035208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 03/01/2023] [Indexed: 04/20/2023]
Abstract
We derive the analytical dispersion relation of a high-energy laser beam's backward stimulated Brillouin scattering (BSBS) in a hot plasma, that accounts both for the random phase plate (RPP) induced spatial shaping and its associated phase randomness. Indeed, phase plates are mandatory in large laser facilities where a precise control of the focal spot size is required. While the focal spot size is well controlled, such techniques produce small scale intensity variations that can trigger laser-plasma instabilities such as BSBS. Quantifying the resulting instability variability is shown to be crucial for understanding accurately the backscattering temporal and spatial growth as well as the asymptotic reflectivity. Our model, validated by means of a large number of three-dimensional paraxial simulations and experimental data, offers three quantitative predictions. The first one addresses the temporal exponential growth of the reflectivity by deriving and solving the BSBS RPP dispersion relation. A large statistical variability of the temporal growth rate is shown to be directly related to the phase plate randomness. Then, we predict the portion of the beam's section that is absolutely unstable, thus helping to precisely assess the validity of the vastly used convective analysis. Finally, a simple analytical correction to the plane wave spatial gain is extracted from our theory giving a practical and effective asymptotic reflectivity prediction that includes the impact of phase plates smoothing techniques. Hence, our study sheds light on the long-time studied BSBS, deleterious to many high-energy experimental studies related to the physics of inertial confinement fusion.
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Affiliation(s)
- C Ruyer
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
| | - A Fusaro
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
| | - A Debayle
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
| | - R Capdessus
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
| | - P Loiseau
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
| | - P E Masson-Laborde
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel, France
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Turnbull D, Katz J, Hinkel DE, Michel P, Chapman T, Divol L, Kur E, MacLaren S, Milder AL, Rosen M, Shvydky A, Zimmerman GB, Froula DH. Beam Spray Thresholds in ICF-Relevant Plasmas. PHYSICAL REVIEW LETTERS 2022; 129:025001. [PMID: 35867466 DOI: 10.1103/physrevlett.129.025001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Beam spray measurements suggest thresholds that are a factor of ≈2 to 15× less than expected based on the filamentation figure of merit often quoted in the literature. In this moderate-intensity regime, the relevant mechanism is forward stimulated Brillouin scattering. Both weak ion acoustic wave damping and thermal enhancement of ion acoustic waves contribute to the low thresholds. Forward stimulated Brillouin scattering imparts a redshift to the transmitted beam. Regarding the specific possibility of beam spray occurring outside the laser entrance holes of an indirectly driven hohlraum, this shift may be the most concerning feature owing to the high sensitivity of crossed-beam energy transfer to the interacting beam wavelengths in the subsequent overlap region.
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Affiliation(s)
- David Turnbull
- University of Rochester Laboratory for Laser Energetics, 250 E River Road, Rochester, New York 14623, USA
| | - Joseph Katz
- University of Rochester Laboratory for Laser Energetics, 250 E River Road, Rochester, New York 14623, USA
| | - Denise E Hinkel
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Pierre Michel
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Thomas Chapman
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Laurent Divol
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Eugene Kur
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Steve MacLaren
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Avram L Milder
- University of Rochester Laboratory for Laser Energetics, 250 E River Road, Rochester, New York 14623, USA
| | - Mordecai Rosen
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Alex Shvydky
- University of Rochester Laboratory for Laser Energetics, 250 E River Road, Rochester, New York 14623, USA
| | - George B Zimmerman
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - Dustin H Froula
- University of Rochester Laboratory for Laser Energetics, 250 E River Road, Rochester, New York 14623, USA
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Hüller S, Raj G, Luo M, Rozmus W, Pesme D. Crossed beam energy transfer between optically smoothed laser beams in inhomogeneous plasmas. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20200038. [PMID: 33040659 PMCID: PMC7658752 DOI: 10.1098/rsta.2020.0038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
Crossed beam energy transfer, CBET, in high-intensity laser-plasma interaction is investigated for the case of optically smoothed laser beams. In the two approaches to laser-driven inertial confinement fusion experiments, the direct-drive and the indirect-drive, CBET is of great importance because it governs the coupling of laser energy to the plasma. We use the two-dimensional wave-coupling code Harmony to simulate the transfer between two laser beams with speckle structure that overlap in a plasma with an inhomogeneous flow profile. We compare the CBET dynamics for laser beams with spatial incoherence and with spatio-temporal incoherence; in particular we apply the smoothing techniques using random phase plates (RPPs) and smoothing by spectral dispersion (SSD), respectively. It is found that for laser beams (wavelength λ0) with intensities (IL) above IL ∼ 2 × 1015 W cm-2(λ0/0.35 µm)-2(Te/keV), both the so-called plasma-induced smoothing as well as self-focusing in intense laser speckles induce temporal incoherence; the latter affects the CBET and the angular distribution of the light transmitted behind the zone of beam overlap. For RPP-smoothed incident beams, the resulting band width of the transmitted light can already be of the same order as the effective band width of the SSD available at major laser facilities. We examine the conditions when spatio-temporal smoothing techniques become efficient for CBET. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 1)'.
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Affiliation(s)
- Stefan Hüller
- Centre de Physique Théorique (CPHT), CNRS, Ecole Polytechnique, IP Paris, 91128 Palaiseau, France
| | - Gaurav Raj
- Centre de Physique Théorique (CPHT), CNRS, Ecole Polytechnique, IP Paris, 91128 Palaiseau, France
| | - Mufei Luo
- Centre de Physique Théorique (CPHT), CNRS, Ecole Polytechnique, IP Paris, 91128 Palaiseau, France
- Key Laboratory for Laser Plasmas (MoE), Department of Physics and Astronomy, Jiao Tong University, Shanghai, China
| | - Wojciech Rozmus
- Theoretical Physics Institute, Department of Physics, University of Alberta, Edmonton, Alberta, Canada
| | - Denis Pesme
- Centre de Physique Théorique (CPHT), CNRS, Ecole Polytechnique, IP Paris, 91128 Palaiseau, France
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Kim J, Andrew P, Reichle R. Plasma-Wall-Interaction Diagnostics in ITER: Dust, Erosion, and Tritium Retention. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst12-a13386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Junghee Kim
- ITER Organization, Diagnostics Division, 13115 Saint-Paul-lez-Durance Cedex, France
| | - P. Andrew
- ITER Organization, Diagnostics Division, 13115 Saint-Paul-lez-Durance Cedex, France
| | - R. Reichle
- ITER Organization, Diagnostics Division, 13115 Saint-Paul-lez-Durance Cedex, France
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Raj G, Hüller S. Impact of Laser Beam Speckle Structure on Crossed Beam Energy Transfer via Beam Deflections and Ponderomotive Self-Focusing. PHYSICAL REVIEW LETTERS 2017; 118:055002. [PMID: 28211711 DOI: 10.1103/physrevlett.118.055002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Indexed: 05/16/2023]
Abstract
The role of laser speckle structure (hot spots) and its ponderomotive self-focusing (PSF), in crossed beam energy transfer (CBET), of smoothed laser beams is investigated in an inhomogeneous expanding plasma. Numerical simulations using the code harmony in two spatial dimensions, demonstrate how self-focusing of laser hot spots in crossed beams can significantly affect the transfer of energy from one beam to the other in addition to the stimulated Brillouin scattering (SBS) process. It is shown that for sufficiently intense laser beams, when the laser hot spots exceed the criterion for self-focusing in a plasma with flow, the angular spread of transmitted light beams increases considerably with the intensity, which arises in particular, in expanding plasma where significant beam deflection is observed. It is shown for the first time that besides SBS, the contribution of speckle structure, PSF, and deflections of the intense hot spots in multiple speckle beams to CBET, therefore matters.
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Affiliation(s)
- G Raj
- Centre de Physique Théorique (CPHT), Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
| | - S Hüller
- Centre de Physique Théorique (CPHT), Ecole Polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
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Hinkel DE, Schneider MB, Young BK, Langdon AB, Williams EA, Rosen MD, Suter LJ. Creation of hot radiation environments in laser-driven targets. PHYSICAL REVIEW LETTERS 2006; 96:195001. [PMID: 16803105 DOI: 10.1103/physrevlett.96.195001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Indexed: 05/10/2023]
Abstract
A hot radiation environment, produced by maximizing laser-energy deposition into a small, high- "can," is a platform being developed for investigations of material properties under extreme conditions. In such small targets, almost doubling the laser energy results in only an incremental increase in the x-radiation flux, and almost no increase in the maximum achieved radiation temperature. That most of this additional laser energy is not deposited within the target is a direct consequence of laser-plasma interactions (LPI) outside of the target, which result in high-angle beams never entering the target late in the laser pulse. Accounting for these processes in the modeling results in quantitative agreement for the first time with experiments using very small cans. These findings have provided the scientific foundation for modifying the target geometry to mitigate the LPI and to achieve higher radiation temperatures.
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Affiliation(s)
- D E Hinkel
- Lawrence Livermore National Laboratory, California 94550, USA
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Lin H. Structure stability of ultraintense laser pulse in transverse homogeneous cold plasma. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 62:5851-4. [PMID: 11089148 DOI: 10.1103/physreve.62.5851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/1999] [Revised: 05/18/2000] [Indexed: 11/07/2022]
Abstract
We study transverse structure symmetry of an ultraintense laser pulse through transverse homogeneous cold plasma. We derive a steady-structure equation of laser pulse and solve it under different on-axis conditions. We compare Hamiltonian values at solutions with different on-axis conditions to examine their relative stability. Numerical results show that for different ionic density, symmetric structure is not always stable relative to asymmetric one of same power. For a given ionic density, whether a symmetric structure is stable is determined by its power. This result agrees with the phenomenon of pulse "head bending", qualitatively. Our theory reveals that, in addition to the plasma's transverse inhomogeneity, there is another mechanism responsible for asymmetric structure.
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Affiliation(s)
- H Lin
- Graduate School, China Academy of Engineering Physics, P.O. Box 2101, Beijing 100088, China
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Montgomery DS, Johnson RP, Rose HA, Cobble JA, Fernandez JC. Flow-induced beam steering in a single laser hot spot. PHYSICAL REVIEW LETTERS 2000; 84:678-681. [PMID: 11017345 DOI: 10.1103/physrevlett.84.678] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/1999] [Indexed: 05/23/2023]
Abstract
The transmitted angular distribution of a 527 nm nearly diffraction-limited laser is measured after it propagates through a plasma with supersonic transverse flow. The laser beam is deflected by as much as 10 degrees and exhibits bowlike features in the flow direction, which is attributed to flow-induced beam steering. The finite interaction volume allows for direct comparison with a 3D hydrodynamic simulation, which is in good agreement with details of the experiment.
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Affiliation(s)
- DS Montgomery
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Moody JD, MacGowan BJ, Hinkel DE, Kruer WL, Williams EA, Estabrook K, Berger RL, Kirkwood RK, Montgomery DS, Shepard TD. First Optical Observation of Intensity Dependent Laser Beam Deflection in a Flowing Plasma. PHYSICAL REVIEW LETTERS 1996; 77:1294-1297. [PMID: 10063040 DOI: 10.1103/physrevlett.77.1294] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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