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Title: Alternative irradiation schemes for NIF and LMJ hohlraums

Abstract

Here, we explore two alternative irradiation schemes for the large ('outer') and small ('inner') angle beams that currently illuminate National Ignition Facility (NIF) and Laser Mégajoule cavities. In the first, while the outer laser beams enter through the usual end laser entrance holes (LEH), the inner beams enter through slots along the cavity axis wall, illuminating the back wall of the cavity. This avoids the current interaction of the inner laser beams with the gold wall bubbles generated by the outer beams, which leads to large time-dependent changes in drive symmetry. Another scheme potentially useful for NIF uses only the outer beams. The radiative losses through the slots or from the use of outer beams only are compensated by using a smaller cavity and LEH.

Authors:
 [1]; ORCiD logo [1];  [1];  [2]
  1. Alternative Energies and Atomic Energy Commission (CEA), Arpajon (France)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1438782
Report Number(s):
LLNL-JRNL-730863
Journal ID: ISSN 0741-3335; TRN: US1900526
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 2; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 70 PLASMA PHYSICS AND FUSION; implosion symmetry; NIF; LMJ; ICF; Laser light absorption

Citation Formats

Bourgade, Jean-Luc, Bowen, Christopher, Gauthier, Pascal, and Landen, Otto. Alternative irradiation schemes for NIF and LMJ hohlraums. United States: N. p., 2017. Web. doi:10.1088/1361-6587/aa9c57.
Bourgade, Jean-Luc, Bowen, Christopher, Gauthier, Pascal, & Landen, Otto. Alternative irradiation schemes for NIF and LMJ hohlraums. United States. doi:10.1088/1361-6587/aa9c57.
Bourgade, Jean-Luc, Bowen, Christopher, Gauthier, Pascal, and Landen, Otto. Wed . "Alternative irradiation schemes for NIF and LMJ hohlraums". United States. doi:10.1088/1361-6587/aa9c57. https://www.osti.gov/servlets/purl/1438782.
@article{osti_1438782,
title = {Alternative irradiation schemes for NIF and LMJ hohlraums},
author = {Bourgade, Jean-Luc and Bowen, Christopher and Gauthier, Pascal and Landen, Otto},
abstractNote = {Here, we explore two alternative irradiation schemes for the large ('outer') and small ('inner') angle beams that currently illuminate National Ignition Facility (NIF) and Laser Mégajoule cavities. In the first, while the outer laser beams enter through the usual end laser entrance holes (LEH), the inner beams enter through slots along the cavity axis wall, illuminating the back wall of the cavity. This avoids the current interaction of the inner laser beams with the gold wall bubbles generated by the outer beams, which leads to large time-dependent changes in drive symmetry. Another scheme potentially useful for NIF uses only the outer beams. The radiative losses through the slots or from the use of outer beams only are compensated by using a smaller cavity and LEH.},
doi = {10.1088/1361-6587/aa9c57},
journal = {Plasma Physics and Controlled Fusion},
number = 2,
volume = 60,
place = {United States},
year = {2017},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Figures / Tables:

Figure 1 Figure 1: Illustrative CAD views of slotraum irradiation scheme. (a) laser beams (inner: dark blue, outer: light blue), axial slots and spots originating from the LEH, (b) specific designs for LMJ (5 slots/side, left) and NIF (4 slots/side, right). The slots are equally spaced in azimuth each serving 2 innermore » quads, with top and bottom slots out of phase to accommodate the specific facility geometry.« less

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