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Modeling turbulent mixing in inertial confinement fusion implosions

Published online by Cambridge University Press:  03 March 2004

YAIR SREBRO ,
DORON KUSHNIR ,
YONI ELBAZ  and
DOV SHVARTS
YAIR SREBRO
Affiliation:
Department of Physics, Ben-Gurion University, Beer-Sheva, Israel Department of Physics, Nuclear Research Center–Negev, Israel
DORON KUSHNIR
Affiliation:
Department of Physics, Nuclear Research Center–Negev, Israel Department of Physics, Hebrew University, Jerusalem, Israel
YONI ELBAZ
Affiliation:
Department of Physics, Ben-Gurion University, Beer-Sheva, Israel Department of Physics, Nuclear Research Center–Negev, Israel
DOV SHVARTS
Affiliation:
Department of Physics, Ben-Gurion University, Beer-Sheva, Israel Department of Physics, Nuclear Research Center–Negev, Israel Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva, Israel
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Abstract

Recent direct drive implosion experiments, performed on the OMEGA laser, have been analyzed by comparing full two-dimensional (2D) and one-dimensional (1D) numerical simulations. The 2D simulations result in a fusion yield higher than experimental results. A simple full-mixing model, leaving only the clean region, overestimates yield degradation. Fully turbulent mixing is expected to develop in most of the mixing region; however regions slightly beyond the radius of the most penetrating spike are expected to remain clean and to contribute to fusion yield. One can correct the mixing model by redefining the clean region. Accounting for this unmixed region results in improved agreement with experimental results. Differences in central pressure, density, temperature, and fusion rate in implosions dominated by low mode number perturbations imply that mix effects might not be limited to the mix region, and that 2D simulations are necessary to describe the large scale flow affecting the central region. The same analysis has been undertaken for implosions with different convergence ratios, but with similar initial perturbation spectra. These implosions should be compared to implosions dominated by high mode number perturbations, which might be described by models based on 1D simulations.

Keywords

Direct numerical simulationsHydrodynamic instabilitiesInertial confinement fusionSecondary instabilitiesTurbulent mixing
Type
Research Article
Information
Laser and Particle Beams , Volume 21 , Issue 3 , July 2003 , pp. 355 - 361
Copyright
© 2003 Cambridge University Press

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