The effects of early time laser drive on hydrodynamic instability growth in National Ignition Facility implosions

Journal Article · Mon Sep 15 04:00:00 EDT 2014 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4896708· OSTI ID:22303441

Peterson, J. L.; Clark, D. S.; Suter, L. J. ^[1]; Masse, L. P. ^[2]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
2. CEA, DAM, DIF, 91297 Arpajon (France)

Defects on inertial confinement fusion capsule surfaces can seed hydrodynamic instability growth and adversely affect capsule performance. The dynamics of shocks launched during the early period of x-ray driven National Ignition Facility (NIF) implosions determine whether perturbations will grow inward or outward at peak implosion velocity and final compression. In particular, the strength of the first shock, launched at the beginning of the laser pulse, plays an important role in determining Richtmyer-Meshkov (RM) oscillations on the ablation front. These surface oscillations can couple to the capsule interior through subsequent shocks before experiencing Rayleigh-Taylor (RT) growth. We compare radiation hydrodynamic simulations of NIF implosions to analytic theories of the ablative RM and RT instabilities to illustrate how early time laser strength can alter peak velocity growth. We develop a model that couples the RM and RT implosion phases and captures key features of full simulations. We also show how three key parameters can control the modal demarcation between outward and inward growth.

• OSTI ID: 22303441
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 9 Vol. 21; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPARATIVE EVALUATIONS
IMPLOSIONS
INERTIAL CONFINEMENT
LASERS
OSCILLATIONS
PEAKS
PERFORMANCE
PLASMA INSTABILITY
SIMULATION
US NATIONAL IGNITION FACILITY
X RADIATION