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Obenschain SP, Schmitt AJ, Bates JW, Wolford MF, Myers MC, McGeoch MW, Karasik M, Weaver JL. Direct drive with the argon fluoride laser as a path to high fusion gain with sub-megajoule laser energy. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20200031. [PMID: 33040651 PMCID: PMC7658751 DOI: 10.1098/rsta.2020.0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
Argon fluoride (ArF) is currently the shortest wavelength laser that can credibly scale to the energy and power required for high gain inertial fusion. ArF's deep ultraviolet light and capability to provide much wider bandwidth than other contemporary inertial confinement fusion (ICF) laser drivers would drastically improve the laser target coupling efficiency and enable substantially higher pressures to drive an implosion. Our radiation hydrodynamics simulations indicate gains greater than 100 are feasible with a sub-megajoule ArF driver. Our laser kinetics simulations indicate that the electron beam-pumped ArF laser can have intrinsic efficiencies of more than 16%, versus about 12% for the next most efficient krypton fluoride excimer laser. We expect at least 10% 'wall plug' efficiency for delivering ArF light to target should be achievable using solid-state pulsed power and efficient electron beam transport to the laser gas that was demonstrated with the U.S. Naval Research Laboratory's Electra facility. These advantages could enable the development of modest size and lower cost fusion power plant modules. This would drastically change the present view on inertial fusion energy as being too expensive and the power plant size too large. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 1)'.
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Affiliation(s)
- S. P. Obenschain
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | - A. J. Schmitt
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | - J. W. Bates
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | - M. F. Wolford
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | - M. C. Myers
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | | | - M. Karasik
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
| | - J. L. Weaver
- Laser Plasma Branch, Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375USA
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Dorrer C, Hill EM, Zuegel JD. High-energy parametric amplification of spectrally incoherent broadband pulses. OPTICS EXPRESS 2020; 28:451-471. [PMID: 32118971 DOI: 10.1364/oe.28.000451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 11/27/2019] [Indexed: 06/10/2023]
Abstract
We study and demonstrate the efficient parametric amplification of spectrally incoherent broadband nanosecond pulses to high energies. Signals composed of mutually incoherent monochromatic lines or amplified spontaneous emission are amplified in a sequence of optical parametric amplifiers pumped at 526.5 nm, with the last amplifier set in a collinear geometry. This configuration results in 70% conversion efficiency from the pump to the combined signal and idler, with a combined energy reaching 400 mJ and an optical spectrum extending over 60 nm around 1053 nm. The spatial, spectral, and temporal properties of the amplified waves are investigated. The demonstrated high conversion efficiency, spectral incoherence, and large bandwidth open the way to a new generation of high-energy, solid-state laser drivers that mitigate laser-plasma instabilities and laser-beam imprint via enhanced spectral bandwidth.
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Bates JW, Myatt JF, Shaw JG, Follett RK, Weaver JL, Lehmberg RH, Obenschain SP. Mitigation of cross-beam energy transfer in inertial-confinement-fusion plasmas with enhanced laser bandwidth. Phys Rev E 2018; 97:061202. [PMID: 30011586 DOI: 10.1103/physreve.97.061202] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Indexed: 11/07/2022]
Abstract
Cross-beam energy transfer (CBET) is a significant energy-loss mechanism in directly driven inertial-confinement-fusion (ICF) targets. One strategy for mitigating CBET is to increase the bandwidth of the laser light, thereby disrupting the resonant three-wave interactions that underlie this nonlinear scattering process. Here, we report on numerical simulations performed with the wave-based code lpse that show a significant reduction in CBET for bandwidths of 2-5 THz (corresponding to a normalized bandwidth of 0.2%-0.6% at a laser wavelength of 351nm) under realistic plasma conditions. Such bandwidths are beyond those available with current high-energy lasers used for ICF, but could be achieved using stimulated rotation Raman scattering in diatomic gases like nitrogen.
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Affiliation(s)
- J W Bates
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - J F Myatt
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada T6G1H9
| | - J G Shaw
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - R K Follett
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J L Weaver
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - R H Lehmberg
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - S P Obenschain
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
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Weaver J, Lehmberg R, Obenschain S, Kehne D, Wolford M. Spectral and far-field broadening due to stimulated rotational Raman scattering driven by the Nike krypton fluoride laser. APPLIED OPTICS 2017; 56:8618-8631. [PMID: 29091672 DOI: 10.1364/ao.56.008618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/25/2017] [Indexed: 06/07/2023]
Abstract
Stimulated rotational Raman scattering (SRRS) in the ultraviolet region (λ=248 nm) has been observed at the Nike laser over extended propagation paths in air during high power operation. Although this phenomenon is not significant for standard operating configurations at Nike, broadening of the laser spectrum and far-field focal profiles has been observed once the intensity-path length product exceeds a threshold of approximately 1 TW/cm. This paper presents experimental results and a new theoretical evaluation of these effects. The observations suggest that significantly broader spectra can be achieved with modest degradation of the final focal distribution. These results point to a possible path for enhanced laser-target coupling with the reduction of laser-plasma instabilities due to broad laser bandwidth produced by the SRRS.
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Eimerl D, Campbell EM, Krupke WF, Zweiback J, Kruer WL, Marozas J, Zuegel J, Myatt J, Kelly J, Froula D, McCrory RL. StarDriver: A Flexible Laser Driver for Inertial Confinement Fusion and High Energy Density Physics. JOURNAL OF FUSION ENERGY 2014. [DOI: 10.1007/s10894-014-9697-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Yavuz DD, Sokolov AV, Harris SE. Eigenvectors of a raman medium. PHYSICAL REVIEW LETTERS 2000; 84:75-78. [PMID: 11015838 DOI: 10.1103/physrevlett.84.75] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/1999] [Indexed: 05/23/2023]
Abstract
We show the existence of discrete sets of Raman sidebands which self-consistently establish a Raman coherence and propagate without change in amplitude and relative phase. Equivalently, there exist periodic femtosecond-time-scale, temporal pulse shapes which propagate without change in shape.
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Affiliation(s)
- DD Yavuz
- Edward L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA
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McDonald GS. Ultrabroad-bandwidth multifrequency Raman soliton pulse trains. OPTICS LETTERS 1995; 20:822-824. [PMID: 19859341 DOI: 10.1364/ol.20.000822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
I have discovered that in the coherent regime of ultrabroad-bandwidth Raman generation, a large number of long-lived soliton pulse trains are spontaneously generated. This novel solution of the dispersionless and highly transient regime, involving more than 40 distinct Raman lines of comparable amplitude, is found to be a strong attractor in the nonlinear dynamics, even when the system is initially far from this limit.
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McDonald GS, New GH, Losev LL, Lutsenko AP, Shaw M. Ultrabroad-bandwidth multifrequency Raman generation. OPTICS LETTERS 1994; 19:1400-1402. [PMID: 19855532 DOI: 10.1364/ol.19.001400] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on the modeling of transient stimulated rotational Raman scattering in H(2) gas. We predict a multifrequency output, spanning a bandwidth greater than the pump frequency, that may be generated without any significant delay with respect to the pump pulses. The roles of dispersion and transiency are quantified.
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