title: Novel characterization of capsule x-ray drive at the National Ignition Facility.
abstract: Indirect drive experiments at the National Ignition Facility are designed to achieve fusion by imploding a fuel capsule with x rays from a laser-driven hohlraum. Previous experiments have been unable to determine whether a deficit in measured ablator implosion velocity relative to simulations is due to inadequate models of the hohlraum or ablator physics. ViewFactor experiments allow for the first time a direct measure of the x-ray drive from the capsule point of view. The experiments show a 15%-25% deficit relative to simulations and thus explain nearly all of the disagreement with the velocity data. In addition, the data from this open geometry provide much greater constraints on a predictive model of laser-driven hohlraum performance than the nominal ignition target.
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: MacLaren
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Schneider
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: K
authors.initials: K
authors.lastname: Widmann
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Hammer
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: B E
authors.initials: BE
authors.lastname: Yoxall
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Moody
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Bell
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Benedetti
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Bradley
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Edwards
authors.affiliation: Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, United Kingdom.
authors.forename: T M
authors.initials: TM
authors.lastname: Guymer
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Hinkel
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: W W
authors.initials: WW
authors.lastname: Hsing
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: M L
authors.initials: ML
authors.lastname: Kervin
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: N B
authors.initials: NB
authors.lastname: Meezan
authors.affiliation: Atomic Weapons Establishment, Aldermaston, Reading RG7 4PR, United Kingdom.
authors.forename: A S
authors.initials: AS
authors.lastname: Moore
authors.affiliation: Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Ralph