Effects of the P2 M-band flux asymmetry of laser-driven gold Hohlraums on the implosion of ICF ignition capsule

Journal Article · Fri Jul 15 04:00:00 EDT 2016 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4958811· OSTI ID:22599998

Li, Yongsheng ^[1]; Gu, Jianfa; Wu, Changshu; Song, Peng; Dai, Zhensheng; Li, Shuanggui; Li, Xin; Kang, Dongguo; Gu, Peijun; Zheng, Wudi; Zou, Shiyang ^[1]; Ding, Yongkun ^[2]; Lan, Ke; Ye, Wenhua ^[1]; Zhang, Weiyan ^[3]

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1. Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)
2. Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)
3. China Academy of Engineering Physics, Mianyang 621900 (China)

Low-mode asymmetries in the laser-indirect-drive inertial confinement fusion implosion experiments conducted on the National Ignition Facility [G. H. Miller et al., Nucl. Fusion 44, S228 (2004)] are deemed the main obstacles hindering further improvement of the nuclear performance of deuterium-tritium-layered capsules. The dominant seeds of these asymmetries include the P2 and P4 asymmetries of x-ray drives and P2 asymmetry introduced by the supporting “tent.” Here, we explore the effects of another possible seed that can lead to low-mode asymmetric implosions, i.e., the M-band flux asymmetry (MFA) in laser-driven cylindrical gold Hohlraums. It is shown that the M-band flux facilitates the ablation and acceleration of the shell, and that positive P2 MFAs can result in negative P2 asymmetries of hot spots and positive P2 asymmetries of shell's ρR. An oblate or toroidal hot spot, depending on the P2 amplitude of MFA, forms at stagnation. The energy loss of such a hot spot via electron thermal conduction is seriously aggravated not only due to the enlarged hot spot surface but also due to the vortices that develop and help transferring thermal energy from the hotter center to the colder margin of such a hot spot. The cliffs of nuclear performance for the two methodologies of applying MFA (i.e., symmetric flux in the presence of MFA and MFA added for symmetric soft x-ray flux) are obtained locating at 9.5% and 5.0% of P2/P0 amplitudes, respectively.

• OSTI ID: 22599998
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 7 Vol. 23; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABLATION
AMPLITUDES
ASYMMETRY
CAPSULES
CYLINDRICAL CONFIGURATION
DEUTERIUM
ELECTRONS
ENERGY LOSSES
GOLD
HOT SPOTS
IMPLOSIONS
INERTIAL CONFINEMENT
LASERS
SOFT X RADIATION
THERMAL CONDUCTION
THERMONUCLEAR IGNITION
TRITIUM
US NATIONAL IGNITION FACILITY