Measurements of laser-plasma instability relevant to ignition hohlraums

Journal Article · Thu May 01 04:00:00 EDT 1997 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.872328· OSTI ID:560635

Fernandez, J C; Bauer, B S; Cobble, J A; DuBois, D F; Kyrala, G A; Montgomery, D S; Rose, H A; Vu, H X; Watt, R G; Wilde, B H; Wilke, M D; Wood, W M ^[1]; Failor, B H ^[2]; Kirkwood, R; MacGowan, B J ^[3]

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1. Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2. Physics International, San Leandro, California 94577 (United States)
3. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

The potential for laser-plasma instability is a serious concern for indirect-drive inertial confinement fusion (ICF), where laser beams illuminate the interior of a cavity (called a hohlraum) to produce x-rays for imploding a fusion capsule symmetrically. The speckled nature of laser beams used in ICF is an important factor in laser-plasma instability processes. For example, models which calculate the spatial growth of convective instability by properly accounting for the laser speckles successfully predict the observed onsets of backscattering due to stimulated Brillouin and Raman scattering instabilities (SBS and SRS). Assuming pump depletion as the only saturation mechanism in these models results in very large predicted levels of SBS and SRS backscattering from the long-scale plasmas expected in ignition hohlraums. However, in the long-scale plasmas studied in the Nova and Trident lasers [E. M. Campbell, Rev. Sci. Instrum. {bold 57}, 2101 (1986) and N. K. Moncur {ital et al.}, Appl. Opt. {bold 34}, 4274 (1995)], SRS and SBS are observed to saturate much below the levels expected from pump depletion. While the mechanism of SBS saturation is not understood at present, the observations of SRS saturation are qualitatively understood. {copyright} {ital 1997 American Institute of Physics.}

• OSTI ID: 560635
• Report Number(s): CONF-961102--
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 4; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BACKSCATTERING
BRILLOUIN EFFECT
IMAGES
INDIRECT DRIVE LASER IMPLOSION
INERTIAL CONFINEMENT
LASER TARGETS
LASER-PRODUCED PLASMA
LIGHT SCATTERING
PLASMA DIAGNOSTICS
PLASMA INSTABILITY
RAMAN EFFECT
THERMONUCLEAR IGNITION