title: Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility.
abstract: An accurate understanding of burn dynamics in implosions of cryogenically layered deuterium (D) and tritium (T) filled capsules, obtained partly through precision diagnosis of these experiments, is essential for assessing the impediments to achieving ignition at the National Ignition Facility. We present measurements of neutrons from such implosions. The apparent ion temperatures T_{ion} are inferred from the variance of the primary neutron spectrum. Consistently higher DT than DD T_{ion} are observed and the difference is seen to increase with increasing apparent DT T_{ion}. The line-of-sight rms variations of both DD and DT T_{ion} are small, ∼150eV, indicating an isotropic source. The DD neutron yields are consistently high relative to the DT neutron yields given the observed T_{ion}. Spatial and temporal variations of the DT temperature and density, DD-DT differential attenuation in the surrounding DT fuel, and fluid motion variations contribute to a DT T_{ion} greater than the DD T_{ion}, but are in a one-dimensional model insufficient to explain the data. We hypothesize that in a three-dimensional interpretation, these effects combined could explain the results.
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: M
authors.initials: M
authors.lastname: Gatu Johnson
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Knauer
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Cerjan
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Eckart
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: G P
authors.initials: GP
authors.lastname: Grim
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: E P
authors.initials: EP
authors.lastname: Hartouni
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: R
authors.initials: R
authors.lastname: Hatarik
authors.affiliation: General Atomics, San Diego, California 92186, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Kilkenny
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Munro
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: D B
authors.initials: DB
authors.lastname: Sayre
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: B K
authors.initials: BK
authors.lastname: Spears
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Bionta
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bond
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Caggiano
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: D
authors.initials: D
authors.lastname: Callahan
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Casey
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: T
authors.initials: T
authors.lastname: Döppner
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Frenje
authors.affiliation: Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA.
authors.forename: V Yu
authors.initials: VY
authors.lastname: Glebov
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: O
authors.initials: O
authors.lastname: Hurricane
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kritcher
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: S
authors.initials: S
authors.lastname: LePape
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: T
authors.initials: T
authors.lastname: Ma
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: A
authors.initials: A
authors.lastname: Mackinnon
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: N
authors.initials: N
authors.lastname: Meezan
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: P
authors.initials: P
authors.lastname: Patel
authors.affiliation: Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Petrasso
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Ralph
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: P T
authors.initials: PT
authors.lastname: Springer
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: C B
authors.initials: CB
authors.lastname: Yeamans