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

Title: Dynamic symmetry of indirectly driven inertial confinement fusion capsules on the National Ignition Facility

Abstract

In order to achieve ignition using inertial confinement fusion it is important to control the growth of low-mode asymmetries as the capsule is compressed. Understanding the time-dependent evolution of the shape of the hot spot and surrounding fuel layer is crucial to optimizing implosion performance. A design and experimental campaign to examine sources of asymmetry and to quantify symmetry throughout the implosion has been developed and executed on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)]. We have constructed a large simulation database of asymmetries applied during different time intervals. Analysis of the database has shown the need to measure and control the hot-spot shape, areal density distribution, and symmetry swings during the implosion. The shape of the hot spot during final stagnation is measured using time-resolved imaging of the self-emission, and information on the shape of the fuel at stagnation can be obtained from Compton radiography [R. Tommasini et al., Phys. Plasmas 18, 056309 (2011)]. For the first time on NIF, two-dimensional inflight radiographs of gas-filled and cryogenic fuel layered capsules have been measured to infer the symmetry of the radiation drive on the capsule. These results have been used to modifymore » the hohlraum geometry and the wavelength tuning to improve the inflight implosion symmetry. We have also expanded our shock timing capabilities by the addition of extra mirrors inside the re-entrant cone to allow the simultaneous measurement of shock symmetry in three locations on a single shot, providing asymmetry information up to Legendre mode 4. By diagnosing the shape at nearly every step of the implosion, we estimate that shape has typically reduced fusion yield by about 50% in ignition experiments.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1] more »; « less
  1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)
Publication Date:
OSTI Identifier:
22300227
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 21; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; 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; ASYMMETRY; CAPSULES; FUSION YIELD; HOT SPOTS; IMPLOSIONS; INERTIAL CONFINEMENT; PLASMA; SHAPE; SIMULATION; STAGNATION; SYMMETRY; TIME DEPENDENCE; TIME RESOLUTION; TWO-DIMENSIONAL CALCULATIONS; US NATIONAL IGNITION FACILITY; WAVELENGTHS

Citation Formats

Town, R. P. J.,, Bradley, D. K., Kritcher, A., Jones, O. S., Rygg, J. R., Tommasini, R., Barrios, M., Benedetti, L. R., Berzak Hopkins, L. F., Celliers, P. M., Döppner, T., Dewald, E. L., Eder, D. C., Field, J. E., Glenn, S. M., Izumi, N., Haan, S. W., Khan, S. F., Ma, T., Milovich, J. L., and others, and. Dynamic symmetry of indirectly driven inertial confinement fusion capsules on the National Ignition Facility. United States: N. p., 2014. Web. doi:10.1063/1.4876609.
Town, R. P. J.,, Bradley, D. K., Kritcher, A., Jones, O. S., Rygg, J. R., Tommasini, R., Barrios, M., Benedetti, L. R., Berzak Hopkins, L. F., Celliers, P. M., Döppner, T., Dewald, E. L., Eder, D. C., Field, J. E., Glenn, S. M., Izumi, N., Haan, S. W., Khan, S. F., Ma, T., Milovich, J. L., & others, and. Dynamic symmetry of indirectly driven inertial confinement fusion capsules on the National Ignition Facility. United States. https://doi.org/10.1063/1.4876609
Town, R. P. J.,, Bradley, D. K., Kritcher, A., Jones, O. S., Rygg, J. R., Tommasini, R., Barrios, M., Benedetti, L. R., Berzak Hopkins, L. F., Celliers, P. M., Döppner, T., Dewald, E. L., Eder, D. C., Field, J. E., Glenn, S. M., Izumi, N., Haan, S. W., Khan, S. F., Ma, T., Milovich, J. L., and others, and. Thu . "Dynamic symmetry of indirectly driven inertial confinement fusion capsules on the National Ignition Facility". United States. https://doi.org/10.1063/1.4876609.
@article{osti_22300227,
title = {Dynamic symmetry of indirectly driven inertial confinement fusion capsules on the National Ignition Facility},
author = {Town, R. P. J., and Bradley, D. K. and Kritcher, A. and Jones, O. S. and Rygg, J. R. and Tommasini, R. and Barrios, M. and Benedetti, L. R. and Berzak Hopkins, L. F. and Celliers, P. M. and Döppner, T. and Dewald, E. L. and Eder, D. C. and Field, J. E. and Glenn, S. M. and Izumi, N. and Haan, S. W. and Khan, S. F. and Ma, T. and Milovich, J. L. and others, and},
abstractNote = {In order to achieve ignition using inertial confinement fusion it is important to control the growth of low-mode asymmetries as the capsule is compressed. Understanding the time-dependent evolution of the shape of the hot spot and surrounding fuel layer is crucial to optimizing implosion performance. A design and experimental campaign to examine sources of asymmetry and to quantify symmetry throughout the implosion has been developed and executed on the National Ignition Facility (NIF) [E. I. Moses et al., Phys. Plasmas 16, 041006 (2009)]. We have constructed a large simulation database of asymmetries applied during different time intervals. Analysis of the database has shown the need to measure and control the hot-spot shape, areal density distribution, and symmetry swings during the implosion. The shape of the hot spot during final stagnation is measured using time-resolved imaging of the self-emission, and information on the shape of the fuel at stagnation can be obtained from Compton radiography [R. Tommasini et al., Phys. Plasmas 18, 056309 (2011)]. For the first time on NIF, two-dimensional inflight radiographs of gas-filled and cryogenic fuel layered capsules have been measured to infer the symmetry of the radiation drive on the capsule. These results have been used to modify the hohlraum geometry and the wavelength tuning to improve the inflight implosion symmetry. We have also expanded our shock timing capabilities by the addition of extra mirrors inside the re-entrant cone to allow the simultaneous measurement of shock symmetry in three locations on a single shot, providing asymmetry information up to Legendre mode 4. By diagnosing the shape at nearly every step of the implosion, we estimate that shape has typically reduced fusion yield by about 50% in ignition experiments.},
doi = {10.1063/1.4876609},
url = {https://www.osti.gov/biblio/22300227}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 21,
place = {United States},
year = {2014},
month = {5}
}