skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Inferring thermal ion temperature and residual kinetic energy from nuclear measurements in inertial confinement fusion implosions

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.5144460· OSTI ID:1634008

In inertial con finement fusion implosion experiments, the presence of residual anisotropic fluid motion within the stagnating hot spot leads to signifi cant variations in ion-temperature measurements using neutron time- of-flight detectors along different lines of sight. The minimum ion-temperature measurement is typically used as representative of the thermal temperature. In the presence of isotropic flows, however, even the minimum DT neutron-inferred ion temperature can be well above the plasma thermal temperature. Using both DD and DT neutron-inferred ion-temperature measurements, we show that it is possible to determine the contribution of isotropic flows and infer the DT burn-averaged thermal ion temperature. The contribution of large isotropic flows on driving the ratio of DD to DT neutron-inferred ion temperatures well below unity and approaching the lower bound of 0.8 is demonstrated in multimode simulations. The minimum DD neutron- inferred ion temperature is determined from the velocity variance analysis, accounting for the presence of isotropic flows. Being close to the DT burn-averaged thermal ion temperature, the inferred DD minimum ion temperatures demonstrate a strong correlation with the experimental yields in the OMEGA implosion database. An analytical expression is also derived to explain the effect of mode ℓ = 1 ion-temperature measurement asymmetry on yield degradations caused by the anisotropic flows.

Research Organization:
Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
NA0003856
OSTI ID:
1634008
Alternate ID(s):
OSTI ID: 1631390
Report Number(s):
2019-218, 2524, 1568; 2019-218, 2524, 1568; TRN: US2201285
Journal Information:
Physics of Plasmas, Vol. 27, Issue 6; Conference: 61. Annual Meeting of the APS Division of Plasma Physics, Fort Lauderdale, FL (United states), 21-25 Oct 2019; ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 10 works
Citation information provided by
Web of Science

References (21)

Impact of temperature-velocity distribution on fusion neutron peak shape journal May 2017
The effect of turbulent kinetic energy on inferred ion temperature from neutron spectra journal July 2014
Metrics for long wavelength asymmetries in inertial confinement fusion implosions on the National Ignition Facility journal April 2014
Impact of three-dimensional hot-spot flow asymmetry on ion-temperature measurements in inertial confinement fusion experiments journal October 2018
Improved formulas for fusion cross-sections and thermal reactivities journal April 1992
Performance metrics for inertial confinement fusion implosions: Aspects of the technical framework for measuring progress in the National Ignition Campaign journal May 2012
Effect of laser illumination nonuniformity on the analysis of time-resolved x-ray measurements in uv spherical transport experiments journal October 1987
Integrated modeling of cryogenic layered highfoot experiments at the NIF journal May 2016
Interpreting inertial fusion neutron spectra journal February 2016
Neutron spectrometry—An essential tool for diagnosing implosions at the National Ignition Facility (invited) journal October 2012
Knudsen Layer Reduction of Fusion Reactivity journal August 2012
Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility journal August 2016
Mode 1 drive asymmetry in inertial confinement fusion implosions on the National Ignition Facility journal April 2014
Relativistic calculation of fusion product spectra for thermonuclear plasmas journal November 1998
A suite of neutron time-of-flight detectors to measure hot-spot motion in direct-drive inertial confinement fusion experiments on OMEGA
  • Mannion, O. M.; Knauer, J. P.; Glebov, V. Yu.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 964 https://doi.org/10.1016/j.nima.2020.163774
journal June 2020
Three-dimensional modeling of the neutron spectrum to infer plasma conditions in cryogenic inertial confinement fusion implosions journal April 2018
Improving the hot-spot pressure and demonstrating ignition hydrodynamic equivalence in cryogenic deuterium–tritium implosions on OMEGA journal May 2014
Effects of residual kinetic energy on yield degradation and ion temperature asymmetries in inertial confinement fusion implosions journal May 2018
Signatures of asymmetry in neutron spectra and images predicted by three-dimensional radiation hydrodynamics simulations of indirect drive implosions journal May 2016
Fusion neutron energies and spectra journal July 1973
The production spectrum in fusion plasmas journal February 2011