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

Title: Yield degradation in inertial-confinement-fusion implosions due to shock-driven kinetic fuel-species stratification and viscous heating

Abstract

Anomalous thermonuclear yield degradation (i.e., that not describable by single-fluid radiation hydrodynamics) in Inertial Confinement Fusion (ICF) implosions is ubiquitously observed in both Omega and National Ignition experiments. Multiple experimental and theoretical studies have been carried out to investigate the origin of such a degradation. Relative concentration changes of fuel-ion species, as well as kinetically enhanced viscous heating, have been among possible explanations proposed for certain classes of ICF experiments. In this study, we investigate the role of such kinetic plasma effects in detail. To this end, we use the iFP code to perform multi-species ion Vlasov-Fokker-Planck simulations of ICF capsule implosions with the fuel comprising various hydrodynamically equivalent mixtures of deuterium (D) and helium-3 (3He), as in the original. We employ the same computational setup as in O. Larroche, which was the first to simulate the experiments kinetically. However, unlike the Larroche study, and in partial agreement with experimental data, we find a systematic yield degradation in multi-species simulations versus averaged-ion simulations when the D-fuel fraction is decreased. This yield degradation originates in the fuel-ion species stratification induced by plasma shocks, which imprints the imploding system and results in the relocation of the D ions from the core ofmore » the capsule to its periphery, thereby reducing the yield relative to a non-separable averaged-ion case. By comparing yields from the averaged-ion kinetic simulations and from the hydrodynamic scaling, we also observe yield variations associated with ion kinetic effects other than fuel-ion stratification, such as ion viscous heating, which is typically neglected in hydrodynamic implosions' simulations. Since our kinetic simulations are driven by hydrodynamic boundary conditions at the fuel-ablator interface, they cannot capture the effects of ion viscosity on the capsule compression, or effects associated with the interface, which are expected to be important. As a result, studies of such effects are left for future work.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1435538
Alternate Identifier(s):
OSTI ID: 1432413
Report Number(s):
LA-UR-18-20952
Journal ID: ISSN 1070-664X; TRN: US1900068
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 25; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; iFP, Rygg effect, species separation, viscous heating

Citation Formats

Taitano, William T., Simakov, Andrei N., Chacon, Luis, and Keenan, Brett. Yield degradation in inertial-confinement-fusion implosions due to shock-driven kinetic fuel-species stratification and viscous heating. United States: N. p., 2018. Web. doi:10.1063/1.5024402.
Taitano, William T., Simakov, Andrei N., Chacon, Luis, & Keenan, Brett. Yield degradation in inertial-confinement-fusion implosions due to shock-driven kinetic fuel-species stratification and viscous heating. United States. doi:10.1063/1.5024402.
Taitano, William T., Simakov, Andrei N., Chacon, Luis, and Keenan, Brett. Mon . "Yield degradation in inertial-confinement-fusion implosions due to shock-driven kinetic fuel-species stratification and viscous heating". United States. doi:10.1063/1.5024402. https://www.osti.gov/servlets/purl/1435538.
@article{osti_1435538,
title = {Yield degradation in inertial-confinement-fusion implosions due to shock-driven kinetic fuel-species stratification and viscous heating},
author = {Taitano, William T. and Simakov, Andrei N. and Chacon, Luis and Keenan, Brett},
abstractNote = {Anomalous thermonuclear yield degradation (i.e., that not describable by single-fluid radiation hydrodynamics) in Inertial Confinement Fusion (ICF) implosions is ubiquitously observed in both Omega and National Ignition experiments. Multiple experimental and theoretical studies have been carried out to investigate the origin of such a degradation. Relative concentration changes of fuel-ion species, as well as kinetically enhanced viscous heating, have been among possible explanations proposed for certain classes of ICF experiments. In this study, we investigate the role of such kinetic plasma effects in detail. To this end, we use the iFP code to perform multi-species ion Vlasov-Fokker-Planck simulations of ICF capsule implosions with the fuel comprising various hydrodynamically equivalent mixtures of deuterium (D) and helium-3 (3He), as in the original. We employ the same computational setup as in O. Larroche, which was the first to simulate the experiments kinetically. However, unlike the Larroche study, and in partial agreement with experimental data, we find a systematic yield degradation in multi-species simulations versus averaged-ion simulations when the D-fuel fraction is decreased. This yield degradation originates in the fuel-ion species stratification induced by plasma shocks, which imprints the imploding system and results in the relocation of the D ions from the core of the capsule to its periphery, thereby reducing the yield relative to a non-separable averaged-ion case. By comparing yields from the averaged-ion kinetic simulations and from the hydrodynamic scaling, we also observe yield variations associated with ion kinetic effects other than fuel-ion stratification, such as ion viscous heating, which is typically neglected in hydrodynamic implosions' simulations. Since our kinetic simulations are driven by hydrodynamic boundary conditions at the fuel-ablator interface, they cannot capture the effects of ion viscosity on the capsule compression, or effects associated with the interface, which are expected to be important. As a result, studies of such effects are left for future work.},
doi = {10.1063/1.5024402},
journal = {Physics of Plasmas},
number = 5,
volume = 25,
place = {United States},
year = {2018},
month = {4}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Deciphering the kinetic structure of multi-ion plasma shocks
journal, November 2017


Ion species stratification within strong shocks in two-ion plasmas
journal, March 2018

  • Keenan, Brett D.; Simakov, Andrei N.; Taitano, William T.
  • Physics of Plasmas, Vol. 25, Issue 3
  • DOI: 10.1063/1.5020156

Inhibition of turbulence in inertial-confinement-fusion hot spots by viscous dissipation
journal, May 2014


An equilibrium-preserving discretization for the nonlinear Rosenbluth–Fokker–Planck operator in arbitrary multi-dimensional geometry
journal, June 2017


Plasma kinetic effects on interfacial mix
journal, November 2016

  • Yin, L.; Albright, B. J.; Taitano, W.
  • Physics of Plasmas, Vol. 23, Issue 11
  • DOI: 10.1063/1.4966562

Tests of the hydrodynamic equivalence of direct-drive implosions with different D2 and He3 mixtures
journal, May 2006

  • Rygg, J. R.; Frenje, J. A.; Li, C. K.
  • Physics of Plasmas, Vol. 13, Issue 5
  • DOI: 10.1063/1.2192759

Influence of high-energy ion loss on DT reaction rate in laser fusion pellets
journal, December 1979


Plasma Adiabatic Lapse Rate
journal, August 2012


The potential role of electric fields and plasma barodiffusion on the inertial confinement fusion database
journal, May 2011

  • Amendt, Peter; Wilks, S. C.; Bellei, C.
  • Physics of Plasmas, Vol. 18, Issue 5
  • DOI: 10.1063/1.3577577

Plasma ion stratification by weak planar shocks
journal, September 2017

  • Simakov, Andrei N.; Keenan, Brett D.; Taitano, William T.
  • Physics of Plasmas, Vol. 24, Issue 9
  • DOI: 10.1063/1.4995427

An adaptive, conservative 0D-2V multispecies Rosenbluth–Fokker–Planck solver for arbitrarily disparate mass and temperature regimes
journal, August 2016


Kinetic simulations of fuel ion transport in ICF target implosions
journal, November 2003

  • Larroche, O.
  • The European Physical Journal D - Atomic, Molecular and Optical Physics, Vol. 27, Issue 2
  • DOI: 10.1140/epjd/e2003-00251-1

A mass, momentum, and energy conserving, fully implicit, scalable algorithm for the multi-dimensional, multi-species Rosenbluth–Fokker–Planck equation
journal, September 2015


Onset of Hydrodynamic Mix in High-Velocity, Highly Compressed Inertial Confinement Fusion Implosions
journal, August 2013


Observation of early shell-dopant mix in OMEGA direct-drive implosions and comparisons with radiation-hydrodynamic simulations
journal, May 2014

  • Baumgaertel, J. A.; Bradley, P. A.; Hsu, S. C.
  • Physics of Plasmas, Vol. 21, Issue 5
  • DOI: 10.1063/1.4881463

Fokker–Planck kinetic modeling of suprathermal α -particles in a fusion plasma
journal, December 2014


Hydrodynamic description of an unmagnetized plasma with multiple ion species. II. Two and three ion species plasmas
journal, March 2016

  • Simakov, Andrei N.; Molvig, Kim
  • Physics of Plasmas, Vol. 23, Issue 3
  • DOI: 10.1063/1.4943895

Species separation in inertial confinement fusion fuels
journal, January 2013

  • Bellei, C.; Amendt, P. A.; Wilks, S. C.
  • Physics of Plasmas, Vol. 20, Issue 1
  • DOI: 10.1063/1.4773291

Kinetic simulation of a plasma collision experiment
journal, August 1993

  • Larroche, Olivier
  • Physics of Fluids B: Plasma Physics, Vol. 5, Issue 8
  • DOI: 10.1063/1.860670

Shock-induced mix across an ideal interface
journal, April 2017

  • Bellei, C.; Amendt, P. A.
  • Physics of Plasmas, Vol. 24, Issue 4
  • DOI: 10.1063/1.4979904

Real viscosity effects in inertial confinement fusion target deuterium–tritium micro-implosions
journal, February 2014

  • Mason, R. J.; Kirkpatrick, R. C.; Faehl, R. J.
  • Physics of Plasmas, Vol. 21, Issue 2
  • DOI: 10.1063/1.4864641

Improved formulas for fusion cross-sections and thermal reactivities
journal, April 1992


Burn Characteristics of Marginal Deuterium-Tritium Microspheres
journal, November 1974


Classical transport equations for burning gas-metal plasmas
journal, September 2014

  • Molvig, Kim; Simakov, Andrei N.; Vold, Erik L.
  • Physics of Plasmas, Vol. 21, Issue 9
  • DOI: 10.1063/1.4895666

Species separation and modification of neutron diagnostics in inertial-confinement fusion
journal, September 2014


Anomalous yield reduction in direct-drive deuterium/tritium implosions due to H3e addition
journal, May 2009

  • Herrmann, H. W.; Langenbrunner, J. R.; Mack, J. M.
  • Physics of Plasmas, Vol. 16, Issue 5
  • DOI: 10.1063/1.3141062

Knudsen Layer Reduction of Fusion Reactivity
journal, August 2012


Revised Knudsen-layer reduction of fusion reactivity
journal, December 2013

  • Albright, B. J.; Molvig, Kim; Huang, C. -K.
  • Physics of Plasmas, Vol. 20, Issue 12
  • DOI: 10.1063/1.4833639

Long Ion Mean-Free Path and Nonequilibrium Radiation Effects on High-Aspect-Ratio Laser-Driven Implosions
journal, May 1989


Simulation and assessment of ion kinetic effects in a direct-drive capsule implosion experiment
journal, October 2016

  • Le, A.; Kwan, T. J. T.; Schmitt, M. J.
  • Physics of Plasmas, Vol. 23, Issue 10
  • DOI: 10.1063/1.4965913

Plasma Barodiffusion in Inertial-Confinement-Fusion Implosions: Application to Observed Yield Anomalies in Thermonuclear Fuel Mixtures
journal, September 2010


Inference of ICF implosion core mix using experimental dataand theoretical mix modeling
journal, December 2009


Ion Fokker-Planck simulation of D- 3 He gas target implosions
journal, December 2012


Plasma viscosity with mass transport in spherical inertial confinement fusion implosion simulations
journal, November 2015

  • Vold, E. L.; Joglekar, A. S.; Ortega, M. I.
  • Physics of Plasmas, Vol. 22, Issue 11
  • DOI: 10.1063/1.4935906

Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions
journal, May 2015

  • Hoffman, Nelson M.; Zimmerman, George B.; Molvig, Kim
  • Physics of Plasmas, Vol. 22, Issue 5
  • DOI: 10.1063/1.4921130

Electron transport in a collisional plasma with multiple ion species
journal, February 2014

  • Simakov, Andrei N.; Molvig, Kim
  • Physics of Plasmas, Vol. 21, Issue 2
  • DOI: 10.1063/1.4867183