title: First Measurements of Fuel-Ablator Interface Instability Growth in Inertial Confinement Fusion Implosions on the National Ignition Facility.
abstract: Direct measurements of hydrodynamic instability growth at the fuel-ablator interface in inertial confinement fusion (ICF) implosions are reported for the first time. These experiments investigate one of the degradation mechanisms behind the lower-than-expected performance of early ICF implosions on the National Ignition Facility. Face-on x-ray radiography is used to measure instability growth occurring between the deuterium-tritium fuel and the plastic ablator from well-characterized perturbations. This growth starts in two ways through separate experiments-either from a preimposed interface modulation or from ablation front feedthrough. These experiments are consistent with analytic modeling and radiation-hydrodynamic simulations, which say that a moderately unstable Atwood number and convergence effects are causing in-flight perturbation growth at the interface. The analysis suggests that feedthrough from outersurface perturbations dominates the interface perturbation growth at mode 60.
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: C R
authors: CR
authors: Weber
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: T
authors: T
authors: Döppner
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: D T
authors: DT
authors: Casey
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: T L
authors: TL
authors: Bunn
authors: General Atomics, San Diego, California 92121, USA.
authors: L C
authors: LC
authors: Carlson
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: R J
authors: RJ
authors: Dylla-Spears
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: B J
authors: BJ
authors: Kozioziemski
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: A G
authors: AG
authors: MacPhee
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.|General Atomics, San Diego, California 92121, USA.
authors: A
authors: A
authors: Nikroo
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: H F
authors: HF
authors: Robey
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: J D
authors: JD
authors: Sater
authors: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors: V A
authors: VA
authors: Smalyuk