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

Title: Robustness studies of ignition targets for the National Ignition Facility in two dimensions

Abstract

Inertial confinement fusion capsules are critically dependent on the integrity of their hot spots to ignite. At the time of ignition, only a certain fractional perturbation of the nominally spherical hot spot boundary can be tolerated and the capsule still achieve ignition. The degree to which the expected hot spot perturbation in any given capsule design is less than this maximum tolerable perturbation is a measure of the ignition margin or robustness of that design. Moreover, since there will inevitably be uncertainties in the initial character and implosion dynamics of any given capsule, all of which can contribute to the eventual hot spot perturbation, quantifying the robustness of that capsule against a range of parameter variations is an important consideration in the capsule design. Here, the robustness of the 300 eV indirect drive target design for the National Ignition Facility [Lindl et al., Phys. Plasmas 11, 339 (2004)] is studied in the parameter space of inner ice roughness, implosion velocity, and capsule scale. A suite of 2000 two-dimensional simulations, run with the radiation hydrodynamics code LASNEX, is used as the data base for the study. For each scale, an ignition region in the two remaining variables is identified and themore » ignition cliff is mapped. In accordance with the theoretical arguments of Levedahl and Lindl [Nucl. Fusion 37, 165 (1997)] and Kishony and Shvarts [Phys. Plasmas 8, 4925 (2001)], the location of this cliff is fitted to a power law of the capsule implosion velocity and scale. It is found that the cliff can be quite well represented in this power law form, and, using this scaling law, an assessment of the overall (one- and two-dimensional) ignition margin of the design can be made. The effect on the ignition margin of an increase or decrease in the density of the target fill gas is also assessed.« less

Authors:
; ;  [1]
  1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
21120382
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 15; Journal Issue: 5; Other Information: DOI: 10.1063/1.2890123; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CAPSULES; DESIGN; DISTURBANCES; HOT SPOTS; HYDRODYNAMICS; IMPLOSIONS; INERTIAL CONFINEMENT; PERTURBATION THEORY; PLASMA; PLASMA SIMULATION; SPHERICAL CONFIGURATION; THERMONUCLEAR IGNITION; THERMONUCLEAR REACTORS; TWO-DIMENSIONAL CALCULATIONS; US NATIONAL IGNITION FACILITY

Citation Formats

Clark, Daniel S, Haan, Steven W, and Salmonson, Jay D. Robustness studies of ignition targets for the National Ignition Facility in two dimensions. United States: N. p., 2008. Web. doi:10.1063/1.2890123.
Clark, Daniel S, Haan, Steven W, & Salmonson, Jay D. Robustness studies of ignition targets for the National Ignition Facility in two dimensions. United States. https://doi.org/10.1063/1.2890123
Clark, Daniel S, Haan, Steven W, and Salmonson, Jay D. 2008. "Robustness studies of ignition targets for the National Ignition Facility in two dimensions". United States. https://doi.org/10.1063/1.2890123.
@article{osti_21120382,
title = {Robustness studies of ignition targets for the National Ignition Facility in two dimensions},
author = {Clark, Daniel S and Haan, Steven W and Salmonson, Jay D},
abstractNote = {Inertial confinement fusion capsules are critically dependent on the integrity of their hot spots to ignite. At the time of ignition, only a certain fractional perturbation of the nominally spherical hot spot boundary can be tolerated and the capsule still achieve ignition. The degree to which the expected hot spot perturbation in any given capsule design is less than this maximum tolerable perturbation is a measure of the ignition margin or robustness of that design. Moreover, since there will inevitably be uncertainties in the initial character and implosion dynamics of any given capsule, all of which can contribute to the eventual hot spot perturbation, quantifying the robustness of that capsule against a range of parameter variations is an important consideration in the capsule design. Here, the robustness of the 300 eV indirect drive target design for the National Ignition Facility [Lindl et al., Phys. Plasmas 11, 339 (2004)] is studied in the parameter space of inner ice roughness, implosion velocity, and capsule scale. A suite of 2000 two-dimensional simulations, run with the radiation hydrodynamics code LASNEX, is used as the data base for the study. For each scale, an ignition region in the two remaining variables is identified and the ignition cliff is mapped. In accordance with the theoretical arguments of Levedahl and Lindl [Nucl. Fusion 37, 165 (1997)] and Kishony and Shvarts [Phys. Plasmas 8, 4925 (2001)], the location of this cliff is fitted to a power law of the capsule implosion velocity and scale. It is found that the cliff can be quite well represented in this power law form, and, using this scaling law, an assessment of the overall (one- and two-dimensional) ignition margin of the design can be made. The effect on the ignition margin of an increase or decrease in the density of the target fill gas is also assessed.},
doi = {10.1063/1.2890123},
url = {https://www.osti.gov/biblio/21120382}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 15,
place = {United States},
year = {Thu May 15 00:00:00 EDT 2008},
month = {Thu May 15 00:00:00 EDT 2008}
}