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Title: Validation of DIrect-Drive Ignition Target Design on OMEGA

Abstract

Under the right conditions, the fusion energy released by imploding a spherical capsule filled with a relatively thin layer of DT ice is predicted to be greater than the energy of the laser pulses used to drive the implosion. The gain of the target implosion is defined to be unity when the energy released from the DT fusion is the same as the energy of the laser light on the target. High target gains are therefore required to produce net energy because of the relatively low energy efficiency of large laser systems. This article will detail the hydrodynamic scaling of the target and explain the criteria that will be used to establish ignition scaling.

Authors:
;
Publication Date:
Research Org.:
Laboratory for Laser Energetics, University of Rochester
Sponsoring Org.:
USDOE
OSTI Identifier:
898577
Report Number(s):
DOE/SF/19460-722
1685; 2006-43; TRN: US0703511
DOE Contract Number:
FC52-92SF19460
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Nuclear Society Newsletter, Fusion Energy Division; Journal Issue: June
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ENERGY EFFICIENCY; HYDRODYNAMICS; IGNITION; IMPLOSIONS; LASERS; NET ENERGY; TARGETS; THERMONUCLEAR REACTORS; DIRECT DRIVE LASER IMPLOSION

Citation Formats

Sangster, T.C., and Soures, J.M. Validation of DIrect-Drive Ignition Target Design on OMEGA. United States: N. p., 2007. Web.
Sangster, T.C., & Soures, J.M. Validation of DIrect-Drive Ignition Target Design on OMEGA. United States.
Sangster, T.C., and Soures, J.M. Thu . "Validation of DIrect-Drive Ignition Target Design on OMEGA". United States. doi:.
@article{osti_898577,
title = {Validation of DIrect-Drive Ignition Target Design on OMEGA},
author = {Sangster, T.C. and Soures, J.M.},
abstractNote = {Under the right conditions, the fusion energy released by imploding a spherical capsule filled with a relatively thin layer of DT ice is predicted to be greater than the energy of the laser pulses used to drive the implosion. The gain of the target implosion is defined to be unity when the energy released from the DT fusion is the same as the energy of the laser light on the target. High target gains are therefore required to produce net energy because of the relatively low energy efficiency of large laser systems. This article will detail the hydrodynamic scaling of the target and explain the criteria that will be used to establish ignition scaling.},
doi = {},
journal = {American Nuclear Society Newsletter, Fusion Energy Division},
number = June,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}
  • The National Ignition Facility (NIF) will be configured in its baseline design to achieve ignition and gain using the indirect drive approach. However, the NIF primary criteria and functional requirements require the NIF design `to not preclude` the ability to conduct inertial confinement fusion experiments using the direct drive approach. The target for direct drive emits fewer cold x-rays than the indirect drive case. This paper describes possible design features of the NIF Target Area to allow conversion to a direct drive capability, and discusses some of the differences in post-shot conditions created compared to indirect drive. 13 refs., 2more » figs., 3 tabs.« less
  • Polar direct drive (PDD) shows promise for achieving direct-drive ignition while the National Ignition Facility (NIF) is initially configured for indirect drive. Experiments have been carried out using 40 repointed beams of the 60-beam OMEGA laser system to approximate the NIF PDD configuration.
  • Polar direct drive (PDD) [S. Skupsky et al., Phys. Plasmas 11 2763 (2004)] shows promise for achieving direct-drive ignition while the National Ignition Facility (NIF) [E. M. Campbell and W. J. Hogan, Plasma Phys. Control. Fusion 41 B39 (1999)] is initially configured for indirect drive. Experiments have been carried out using 40 repointed beams of the 60-beam OMEGA laser system [T. R. Boehly et al., Rev. Sci. Instrum. 66 508 (1995)] to approximate the NIF PDD configuration. Backlit x-ray framing-camera images of D{sub 2}-filled spherical CH capsules show a characteristic nonuniformity pattern that is in close agreement with predictions. Saturnmore » targets (similar capsules surrounded by a plastic ring) increase the drive on the equator, suggesting that highly symmetric PDD implosions may be possible with appropriate tuning. Two-dimensional (2D) simulations reproduced the approximately threefold reduction in yield found for the non-Saturn PDD capsules. Preliminary simulations for a NIF Saturn design predict a high gain close to the 1D prediction. These results increase the prospects of obtaining direct-drive ignition with the initial NIF configuration.« less
  • We present for the first time the experimental validation of the nonlocal thermal-transport model for a National Ignition Facility relevant laser intensity of ~10^15 W/cm^2 on OMEGA. The measured thin target trajectories are in good agreement with predictions based on the nonlocal model over the full range of laser intensities from 2 x 10^14 to 10^15 W/cm^2. The standard local thermal-transport model with a constant flux limiter of 0.06 disagrees with experimental measurements at a high intensity of ~10^15 W/cm^2 but agrees at lower intensities. These results show the significance of nonlocal effects for direct-drive ignition designs.
  • Within the US ICF program the direct-drive method has been chosen using the OMEGA facility based on the Neodymium glass laser. Requirements for the future experiments are reviewed and the design is outlined. {copyright} {ital 1996 American Institute of Physics.}