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Title: Symmetry control in subscale near-vacuum hohlraums

Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. In conclusion, specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.
Authors:
 [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ;  [5] ; ORCiD logo [5] ;  [1] ;  [1] ;  [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  5. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-687080
Journal ID: ISSN 1070-664X
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION
OSTI Identifier:
1377764
Alternate Identifier(s):
OSTI ID: 1377764