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Title: Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning

Abstract

The effects of frequency detuning laser beams in direct-drive symmetric implosions were investigated with a 3-D cross-beam energy transfer (CBET) model. Our model shows that interactions between beams with relative angles between 45° and 90° are most significant for CBET in OMEGA direct-drive implosions. There is no net exchange in power between beams but there is significant redistribution of power from the ingoing central portion of the beam profile to the outgoing edge as it is exiting the plasma, reducing the total absorbed power. Furthermore, redistribution of laser power because of CBET increases the root-mean-square (rms) absorption nonuniformity by an order of magnitude. CBET mitigation by shifting relative wavelengths of three groups of laser beams fed by each of the different beamlines was modeled. At an on-target wavelength shift of Δλ ~ 10 Å, the total laser absorption was maximized, and the rms absorption nonuniformity was near minimum. In order to completely decouple the three groups of beams from each other requires wavelength shifts Δλ > 30 Å.

Authors:
 [1];  [1];  [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Publication Date:
Research Org.:
Univ. of Rochester, NY (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1366441
Alternate Identifier(s):
OSTI ID: 1372508
Report Number(s):
2017-11, 1342
Journal ID: ISSN 1070-664X; 2017-11, 1342, 2296
Grant/Contract Number:  
NA0001944
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 24; Journal Issue: 6; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Edgell, D. H., Follett, R. K., Igumenshchev, I. V., Myatt, J. F., Shaw, J. G., and Froula, D. H. Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning. United States: N. p., 2017. Web. doi:10.1063/1.4985315.
Edgell, D. H., Follett, R. K., Igumenshchev, I. V., Myatt, J. F., Shaw, J. G., & Froula, D. H. Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning. United States. doi:10.1063/1.4985315.
Edgell, D. H., Follett, R. K., Igumenshchev, I. V., Myatt, J. F., Shaw, J. G., and Froula, D. H. Tue . "Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning". United States. doi:10.1063/1.4985315. https://www.osti.gov/servlets/purl/1366441.
@article{osti_1366441,
title = {Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning},
author = {Edgell, D. H. and Follett, R. K. and Igumenshchev, I. V. and Myatt, J. F. and Shaw, J. G. and Froula, D. H.},
abstractNote = {The effects of frequency detuning laser beams in direct-drive symmetric implosions were investigated with a 3-D cross-beam energy transfer (CBET) model. Our model shows that interactions between beams with relative angles between 45° and 90° are most significant for CBET in OMEGA direct-drive implosions. There is no net exchange in power between beams but there is significant redistribution of power from the ingoing central portion of the beam profile to the outgoing edge as it is exiting the plasma, reducing the total absorbed power. Furthermore, redistribution of laser power because of CBET increases the root-mean-square (rms) absorption nonuniformity by an order of magnitude. CBET mitigation by shifting relative wavelengths of three groups of laser beams fed by each of the different beamlines was modeled. At an on-target wavelength shift of Δλ ~ 10 Å, the total laser absorption was maximized, and the rms absorption nonuniformity was near minimum. In order to completely decouple the three groups of beams from each other requires wavelength shifts Δλ > 30 Å.},
doi = {10.1063/1.4985315},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 6,
volume = 24,
place = {United States},
year = {2017},
month = {6}
}

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Cited by: 2 works
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Works referenced in this record:

Crossed-beam energy transfer in direct-drive implosions
journal, May 2012

  • Igumenshchev, I. V.; Seka, W.; Edgell, D. H.
  • Physics of Plasmas, Vol. 19, Issue 5, Article No. 056314
  • DOI: 10.1063/1.4718594

Direct-drive laser fusion: Status and prospects
journal, May 1998

  • Bodner, Stephen E.; Colombant, Denis G.; Gardner, John H.
  • Physics of Plasmas, Vol. 5, Issue 5, p. 1901-1918
  • DOI: 10.1063/1.872861