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Title: Ion-kinetic simulations of D- 3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number

Abstract

Experiments designed to investigate the transition to non-collisional behavior in D 3He-gas inertial confinement fusion target implosions display increasingly large discrepancies with respect to simulations by standard hydrodynamics codes as the expected ion mean-free-paths λ c increase with respect to the target radius R (i.e., when the Knudsen number N K = λ c/R grows). To take properly into account large N K's, multi-ion-species Vlasov-Fokker-Planck computations of the inner gas in the capsules have been performed, for two different values of N K, one moderate and one large. The results, including nuclear yield, reactivity-weighted ion temperatures, nuclear emissivities, and surface brightness, have been compared with the experimental data and with the results of hydrodynamical simulations, some of which include an ad hocmodeling of kinetic effects. The experimental results are quite accurately rendered by the kinetic calculations in the smaller-N K case, much better than by the hydrodynamical calculations. The kinetic effects at play in this case are thus correctly understood. However, in the higher-N K case, the agreement is much worse. Furthermore, the remaining discrepancies are shown to arise from kinetic phenomena (e.g., inter-species diffusion) occurring at the gas-pusher interface, which should be investigated in the future work.

Authors:
 [1];  [2];  [3];  [4];  [5];  [6];  [2];  [6]
  1. CEA DIF, Arpajon Cedex (France)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Univ. of Rochester, Rochester, NY (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. Univ. di Roma "La Sapienza" and CNISM, Roma (Italy)
  6. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab., Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1281685
Report Number(s):
LLNL-JRNL-696097
Journal ID: ISSN 1070-664X
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 1; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION; hydrological modeling; interface diffusion; plasma temperature; helium-3; collision theories

Citation Formats

Larroche, O., Rinderknecht, H. G., Rosenberg, M. J., Hoffman, N. M., Atzeni, S., Petrasso, R. D., Amendt, P. A., and Seguin, F. H. Ion-kinetic simulations of D-3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number. United States: N. p., 2016. Web. doi:10.1063/1.4939025.
Larroche, O., Rinderknecht, H. G., Rosenberg, M. J., Hoffman, N. M., Atzeni, S., Petrasso, R. D., Amendt, P. A., & Seguin, F. H. Ion-kinetic simulations of D-3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number. United States. doi:10.1063/1.4939025.
Larroche, O., Rinderknecht, H. G., Rosenberg, M. J., Hoffman, N. M., Atzeni, S., Petrasso, R. D., Amendt, P. A., and Seguin, F. H. Wed . "Ion-kinetic simulations of D-3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number". United States. doi:10.1063/1.4939025. https://www.osti.gov/servlets/purl/1281685.
@article{osti_1281685,
title = {Ion-kinetic simulations of D-3He gas-filled inertial confinement fusion target implosions with moderate to large Knudsen number},
author = {Larroche, O. and Rinderknecht, H. G. and Rosenberg, M. J. and Hoffman, N. M. and Atzeni, S. and Petrasso, R. D. and Amendt, P. A. and Seguin, F. H.},
abstractNote = {Experiments designed to investigate the transition to non-collisional behavior in D3He-gas inertial confinement fusion target implosions display increasingly large discrepancies with respect to simulations by standard hydrodynamics codes as the expected ion mean-free-paths λc increase with respect to the target radius R (i.e., when the Knudsen number NK = λc/R grows). To take properly into account large NK's, multi-ion-species Vlasov-Fokker-Planck computations of the inner gas in the capsules have been performed, for two different values of NK, one moderate and one large. The results, including nuclear yield, reactivity-weighted ion temperatures, nuclear emissivities, and surface brightness, have been compared with the experimental data and with the results of hydrodynamical simulations, some of which include an ad hocmodeling of kinetic effects. The experimental results are quite accurately rendered by the kinetic calculations in the smaller-NK case, much better than by the hydrodynamical calculations. The kinetic effects at play in this case are thus correctly understood. However, in the higher-NK case, the agreement is much worse. Furthermore, the remaining discrepancies are shown to arise from kinetic phenomena (e.g., inter-species diffusion) occurring at the gas-pusher interface, which should be investigated in the future work.},
doi = {10.1063/1.4939025},
journal = {Physics of Plasmas},
number = 1,
volume = 23,
place = {United States},
year = {2016},
month = {1}
}

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