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Title: Symmetry control in subscale near-vacuum hohlraums

Abstract

Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [1];  [2];  [2]; ;  [2]
  1. National Ignition Facility, LLNL, Livermore, California 94550 (United States)
  2. Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139 (United States)
Publication Date:
OSTI Identifier:
22600198
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 23; Journal Issue: 5; Other Information: (c) 2016 Author(s); 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; BALANCES; BEAMS; CAPSULES; COMPUTERIZED SIMULATION; CONES; CONTROL; DIAGNOSIS; HOT SPOTS; HYDRODYNAMIC MODEL; IMPLOSIONS; INERTIAL CONFINEMENT; LASERS; LENGTH; PULSES; REFLECTION; SYMMETRY; THERMONUCLEAR IGNITION; US NATIONAL IGNITION FACILITY

Citation Formats

Turnbull, D., E-mail: turnbull2@llnl.gov, Berzak Hopkins, L. F., Le Pape, S., Divol, L., Meezan, N., Landen, O. L., Ho, D. D., Ross, J. S., Khan, S., Pak, A., Dewald, E. L., Callahan, D. A., Hurricane, O., Hsing, W. W., Edwards, M. J., Mackinnon, A., Linac Coherent Light Source, SLAC, Menlo Park, California 94025, Zylstra, A. B., Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Rinderknecht, H. G., National Ignition Facility, LLNL, Livermore, California 94550, Sio, H., and Petrasso, R. D. Symmetry control in subscale near-vacuum hohlraums. United States: N. p., 2016. Web. doi:10.1063/1.4950825.
Turnbull, D., E-mail: turnbull2@llnl.gov, Berzak Hopkins, L. F., Le Pape, S., Divol, L., Meezan, N., Landen, O. L., Ho, D. D., Ross, J. S., Khan, S., Pak, A., Dewald, E. L., Callahan, D. A., Hurricane, O., Hsing, W. W., Edwards, M. J., Mackinnon, A., Linac Coherent Light Source, SLAC, Menlo Park, California 94025, Zylstra, A. B., Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Rinderknecht, H. G., National Ignition Facility, LLNL, Livermore, California 94550, Sio, H., & Petrasso, R. D. Symmetry control in subscale near-vacuum hohlraums. United States. doi:10.1063/1.4950825.
Turnbull, D., E-mail: turnbull2@llnl.gov, Berzak Hopkins, L. F., Le Pape, S., Divol, L., Meezan, N., Landen, O. L., Ho, D. D., Ross, J. S., Khan, S., Pak, A., Dewald, E. L., Callahan, D. A., Hurricane, O., Hsing, W. W., Edwards, M. J., Mackinnon, A., Linac Coherent Light Source, SLAC, Menlo Park, California 94025, Zylstra, A. B., Los Alamos National Laboratory, Los Alamos, New Mexico 87545, Rinderknecht, H. G., National Ignition Facility, LLNL, Livermore, California 94550, Sio, H., and Petrasso, R. D. Sun . "Symmetry control in subscale near-vacuum hohlraums". United States. doi:10.1063/1.4950825.
@article{osti_22600198,
title = {Symmetry control in subscale near-vacuum hohlraums},
author = {Turnbull, D., E-mail: turnbull2@llnl.gov and Berzak Hopkins, L. F. and Le Pape, S. and Divol, L. and Meezan, N. and Landen, O. L. and Ho, D. D. and Ross, J. S. and Khan, S. and Pak, A. and Dewald, E. L. and Callahan, D. A. and Hurricane, O. and Hsing, W. W. and Edwards, M. J. and Mackinnon, A. and Linac Coherent Light Source, SLAC, Menlo Park, California 94025 and Zylstra, A. B. and Los Alamos National Laboratory, Los Alamos, New Mexico 87545 and Rinderknecht, H. G. and National Ignition Facility, LLNL, Livermore, California 94550 and Sio, H. and Petrasso, R. D.},
abstractNote = {Controlling the symmetry of indirect-drive inertial confinement fusion implosions remains a key challenge. Increasing the ratio of the hohlraum diameter to the capsule diameter (case-to-capsule ratio, or CCR) facilitates symmetry tuning. By varying the balance of energy between the inner and outer cones as well as the incident laser pulse length, we demonstrate the ability to tune from oblate, through round, to prolate at a CCR of 3.2 in near-vacuum hohlraums at the National Ignition Facility, developing empirical playbooks along the way for cone fraction sensitivity of various laser pulse epochs. Radiation-hydrodynamic simulations with enhanced inner beam propagation reproduce most experimental observables, including hot spot shape, for a majority of implosions. Specular reflections are used to diagnose the limits of inner beam propagation as a function of pulse length.},
doi = {10.1063/1.4950825},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 23,
place = {United States},
year = {2016},
month = {5}
}