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Title: Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility

Journal Article · · Physical Review E

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 Tion are inferred from the variance of the primary neutron spectrum. Consistently higher DT than DD Tion are observed and the difference is seen to increase with increasing apparent DT Tion. The line-of-sight rms variations of both DD and DT Tion are small, ~150 eV, indicating an isotropic source. The DD neutron yields are consistently high relative to the DT neutron yields given the observed Tion. 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 Tion > DD Tion, but are in a one-dimensional model insufficient to explain the data. Lastly, we hypothesize that in a three-dimensional interpretation, these effects combined could explain the results.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC52-07NA27344; NA0001857; NA0002949
OSTI ID:
1313547
Alternate ID(s):
OSTI ID: 1294718; OSTI ID: 1324684
Report Number(s):
LLNL-JRNL-682118; PLEEE8
Journal Information:
Physical Review E, Vol. 94, Issue 2; ISSN 2470-0045
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 46 works
Citation information provided by
Web of Science

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Cited By (22)

Observation of persistent species temperature separation in inertial confinement fusion mixtures journal January 2020
Impact of temperature-velocity distribution on fusion neutron peak shape journal May 2017
The role of hot spot mix in the low-foot and high-foot implosions on the NIF journal May 2017
Variable convergence liquid layer implosions on the National Ignition Facility journal May 2018
In-flight neutron spectra as an ICF diagnostic for implosion asymmetries journal February 2018
Bulk hydrodynamic stability and turbulent saturation in compressing hot spots journal April 2018
Effects of residual kinetic energy on yield degradation and ion temperature asymmetries in inertial confinement fusion implosions journal May 2018
Synthetic nuclear diagnostics for inferring plasma properties of inertial confinement fusion implosions journal December 2018
Measurement of apparent ion temperature using the magnetic recoil spectrometer at the OMEGA laser facility journal October 2018
Absolute calibration of a time-resolved high resolution x-ray spectrometer for the National Ignition Facility (invited) journal October 2018
The effect of scattered neutrons on the ion temperature measurement with different line-of-sight on the SGIII laser facility journal January 2019
Impact of imposed mode 2 laser drive asymmetry on inertial confinement fusion implosions journal January 2019
Approaching a burning plasma on the NIF journal May 2019
Three-dimensional modeling and hydrodynamic scaling of National Ignition Facility implosions journal May 2019
Interpreting the electron temperature inferred from x-ray continuum emission for direct-drive inertial confinement fusion implosions on OMEGA journal August 2019
Neutron backscatter edge: A measure of the hydrodynamic properties of the dense DT fuel at stagnation in ICF experiments journal January 2020
Dynamic high energy density plasma environments at the National Ignition Facility for nuclear science research journal February 2018
Capsule modeling of high foot implosion experiments on the National Ignition Facility journal March 2017
Kinetic physics in ICF: present understanding and future directions journal April 2018
Spectral composition of thermonuclear particle and recoil nuclear emissions from laser fusion targets intended for modern ignition experiments journal June 2018
Compression and burning of a direct-driven thermonuclear target under the conditions of inhomogeneous heating by a multi-beam megajoule laser journal January 2019
Progress of indirect drive inertial confinement fusion in the United States journal July 2019