title: 2D X-ray radiography of imploding capsules at the national ignition facility.
abstract: First measurements of the in-flight shape of imploding inertial confinement fusion (ICF) capsules at the National Ignition Facility (NIF) were obtained by using two-dimensional x-ray radiography. The sequence of area-backlit, time-gated pinhole images is analyzed for implosion velocity, low-mode shape and density asymmetries, and the absolute offset and center-of-mass velocity of the capsule shell. The in-flight shell is often observed to be asymmetric even when the concomitant core self-emission is round. A ∼ 15 μm shell asymmetry amplitude of the Y(40) spherical harmonic mode was observed for standard NIF ICF hohlraums at a shell radius of ∼ 200 μm (capsule at ∼ 5× radial compression). This asymmetry is mitigated by a ∼ 10% increase in the hohlraum length.
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Rygg
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: O S
authors.initials: OS
authors.lastname: Jones
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Field
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Barrios
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: L R
authors.initials: LR
authors.lastname: Benedetti
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: Collins
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Eder
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Edwards
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Kline
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Kroll
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: O L
authors.initials: OL
authors.lastname: Landen
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: T
authors.initials: T
authors.lastname: Ma
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: A
authors.initials: A
authors.lastname: Pak
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Peterson
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: K
authors.initials: K
authors.lastname: Raman
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: R P J
authors.initials: RP
authors.lastname: Town
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94551, USA.
authors.forename: D K
authors.initials: DK
authors.lastname: Bradley
mesh_terms: D003198:Computer Simulation; D005857:Germanium / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008962:Models, Theoretical; D011859:Radiography / Q000379:methods*; D013816:Thermodynamics; D014965:X-Rays
chemical_list: D005857:Germanium; D006046:Gold