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Title: A plasma amplifier to combine multiple beams at NIF

Combining laser beams in a plasma is enabled by seeded stimulated Brillouin scattering which allows cross-beam energy transfer (CBET) to occur and re-distributes the energy between beams that cross with different incident angles and small differences in wavelength [Kirkwood et al. Phys. Plasmas 4, 1800 (1997)]. Indirect-drive implosions at the National Ignition Facility (NIF) [Haynam et al. Appl. Opt. 46, 3276–3303 (2007)] have controlled drive symmetry by using plasma amplifiers to transfer energy between beams [Kirkwood et al., Plasma Phys. Controlled Fusion 55, 103001 (2013); Lindl et al., Phys. Plasmas 21, 020501 (2014); and Hurricane et al. Nature 506, 343–348 (2014)]. Here, we show that the existing models are well enough validated by experiments to allow a design of a plasma beam combiner that, once optimized, is expected to produce a pulse of light in a single beam with the energy greatly enhanced over existing sources. The scheme combines up to 61 NIF beams with 120 kJ of available energy into a single f/20 beam with a 1 ns pulse duration and a 351 nm wavelength by both resonant and off-resonance CBET. Initial experiments are also described that have already succeeded in producing a 4 kJ, 1 ns pulse inmore » a single beam by combination of up to eight incident pump beams containing <1.1 kJ/beam, which are maintained near resonance for CBET in a plasma that is formed by 60 pre-heating beams [Kirkwood et al., Nat. Phys. 14, 80 (2018)].« less
Authors:
 [1] ; ORCiD logo [2] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Publication Date:
Report Number(s):
LLNL-JRNL-741662
Journal ID: ISSN 1070-664X; 895784
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; phase transitions; intense particle beams; plasma confinement; plasma instabilities; hurricanes; x-rays; stimulated scattering; plasma density; electromagnetic radiation
OSTI Identifier:
1458628
Alternate Identifier(s):
OSTI ID: 1425537