Probing the deep nonlinear stage of the ablative Rayleigh-Taylor instability in indirect drive experiments on the National Ignition Facility

Journal Article · Fri May 15 00:00:00 EDT 2015 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.4918356· OSTI ID:22410398

Masse, L.; Liberatore, S.; Loiseau, P.; Masson-Laborde, P. E.; Jacquet, L. ^[1]; Martinez, D.; Moore, A. S.; Seugling, R.; Felker, S.; Haan, S. W.; Remington, B. A.; Smalyuk, V. A. ^[2]; Farrell, M.; Giraldez, E.; Nikroo, A. ^[3]

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1. CEA, DAM, DIF, F-91297 Arpajon (France)
2. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
3. General Atomics, San Diego, California 92121 (United States)

Academic tests in physical regimes not encountered in Inertial Confinement Fusion will help to build a better understanding of hydrodynamic instabilities and constitute the scientifically grounded validation complementary to fully integrated experiments. Under the National Ignition Facility (NIF) Discovery Science program, recent indirect drive experiments have been carried out to study the ablative Rayleigh-Taylor Instability (RTI) in transition from weakly nonlinear to highly nonlinear regime [A. Casner et al., Phys. Plasmas 19, 082708 (2012)]. In these experiments, a modulated package is accelerated by a 175 eV radiative temperature plateau created by a room temperature gas-filled platform irradiated by 60 NIF laser beams. The unique capabilities of the NIF are harnessed to accelerate this planar sample over much larger distances (≃1.4 mm) and longer time periods (≃12 ns) than previously achieved. This extended acceleration could eventually allow entering into a turbulent-like regime not precluded by the theory for the RTI at the ablation front. Simultaneous measurements of the foil trajectory and the subsequent RTI growth are performed and compared with radiative hydrodynamics simulations. We present RTI growth measurements for two-dimensional single-mode and broadband multimode modulations. The dependence of RTI growth on initial conditions and ablative stabilization is emphasized, and we demonstrate for the first time in indirect-drive a bubble-competition, bubble-merger regime for the RTI at ablation front.

• OSTI ID: 22410398
• Journal Information: Physics of Plasmas, Vol. 22, Issue 5; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABLATION
BUBBLES
COMPUTERIZED SIMULATION
EXPERIMENTAL DATA
HYDRODYNAMICS
INERTIAL CONFINEMENT
LASERS
MODULATION
NONLINEAR PROBLEMS
PHOTON BEAMS
PROBES
RAYLEIGH-TAYLOR INSTABILITY
STABILIZATION
TEMPERATURE RANGE 0273-0400 K
TWO-DIMENSIONAL CALCULATIONS
US NATIONAL IGNITION FACILITY