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

This content will become publicly available on June 5, 2020

Title: Determining acceptable limits of fast-electron preheat in direct-drive-ignition–scale target designs

Abstract

In direct-drive–ignition designs, preheat by fast electrons created by the two-plasmon–decay or stimulated Raman instabilities can increase the adiabat in the fuel layer and reduce compression and neutron yield. Since eliminating the preheat entirely is a major challenge, it is necessary to understand the levels of preheat that preclude ignition in a direct-drive target. Two 1-D ignition-scale target designs serve as the basis for examining the effects of synthetically increasing the levels of fast electrons using the 1-D radiation–hydrodynamic code LILAC, which includes two models of fast-electron transport. The first is an ignition design adapted from a 2-D polar-direct-drive (PDD) design for the National Ignition Facility (NIF). The second is derived from the first but uses a laser pulse that generates stronger shocks and a higher fuel adiabat. This more stable “alpha-burner” design approaches ignition and achieves yield multiplication as a result of alpha heating. The designs are then re optimized to recover performance. The igniting design, when fast-electron transport was modeled with diffusion, was found to tolerate 50% more fast-electron preheat of the cold (sub-50 eV) DT ice layer when the laser pulse was optimized using the optimizer Telios. When a straight-line fast-electron transport model was used, the effectsmore » of optimization were negligible. For the alpha-burner design, an increase of over a factor of at least 3 in the tolerable level of fast-electron preheat was obtained for both transport models.« less

Authors:
 [1];  [1];  [2]
  1. Univ. of Rochester, Rochester, NY (United States). Lab. for Laser Energetics
  2. Webster Schroeder High School, Webster, NY (United States); Harvey Mudd College, Claremont, CA (United States)
Publication Date:
Research Org.:
Univ. of Rochester, Rochester, NY (United States). Lab. for Laser Energetics
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
Contributing Org.:
Laboratory for Laser Energetics, University of Rochester
OSTI Identifier:
1526436
Report Number(s):
2018-90; 1501
Journal ID: ISSN 1070-664X; 2018-90, 2460, 1501
Grant/Contract Number:  
NA0003856
Resource Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 26; Journal Issue: 6; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English

Citation Formats

Delettrez, J. A., Collins, T. J. B., and Ye, C. Determining acceptable limits of fast-electron preheat in direct-drive-ignition–scale target designs. United States: N. p., 2019. Web. doi:10.1063/1.5089890.
Delettrez, J. A., Collins, T. J. B., & Ye, C. Determining acceptable limits of fast-electron preheat in direct-drive-ignition–scale target designs. United States. doi:10.1063/1.5089890.
Delettrez, J. A., Collins, T. J. B., and Ye, C. Wed . "Determining acceptable limits of fast-electron preheat in direct-drive-ignition–scale target designs". United States. doi:10.1063/1.5089890.
@article{osti_1526436,
title = {Determining acceptable limits of fast-electron preheat in direct-drive-ignition–scale target designs},
author = {Delettrez, J. A. and Collins, T. J. B. and Ye, C.},
abstractNote = {In direct-drive–ignition designs, preheat by fast electrons created by the two-plasmon–decay or stimulated Raman instabilities can increase the adiabat in the fuel layer and reduce compression and neutron yield. Since eliminating the preheat entirely is a major challenge, it is necessary to understand the levels of preheat that preclude ignition in a direct-drive target. Two 1-D ignition-scale target designs serve as the basis for examining the effects of synthetically increasing the levels of fast electrons using the 1-D radiation–hydrodynamic code LILAC, which includes two models of fast-electron transport. The first is an ignition design adapted from a 2-D polar-direct-drive (PDD) design for the National Ignition Facility (NIF). The second is derived from the first but uses a laser pulse that generates stronger shocks and a higher fuel adiabat. This more stable “alpha-burner” design approaches ignition and achieves yield multiplication as a result of alpha heating. The designs are then re optimized to recover performance. The igniting design, when fast-electron transport was modeled with diffusion, was found to tolerate 50% more fast-electron preheat of the cold (sub-50 eV) DT ice layer when the laser pulse was optimized using the optimizer Telios. When a straight-line fast-electron transport model was used, the effects of optimization were negligible. For the alpha-burner design, an increase of over a factor of at least 3 in the tolerable level of fast-electron preheat was obtained for both transport models.},
doi = {10.1063/1.5089890},
journal = {Physics of Plasmas},
number = 6,
volume = 26,
place = {United States},
year = {2019},
month = {6}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 5, 2020
Publisher's Version of Record

Save / Share:

Works referenced in this record:

Polar direct drive on the National Ignition Facility
journal, May 2004

  • Skupsky, S.; Marozas, J. A.; Craxton, R. S.
  • Physics of Plasmas, Vol. 11, Issue 5, p. 2763-2770
  • DOI: 10.1063/1.1689665