Symmetry control in subscale near-vacuum hohlraums
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
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.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344
- OSTI ID:
- 1377764
- Alternate ID(s):
- OSTI ID: 1253821
- Report Number(s):
- LLNL-JRNL-687080
- Journal Information:
- Physics of Plasmas, Vol. 23, Issue 5; ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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