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Title: Using VISAR to assess the M-band isotropy in hohlraums

In laser based radiation flow experiments, drive variability can often overwhelm the physics sensitivity that one seeks to quantify. Hohlraums can help by providing a more symmetrized, Planckian-like source. However, at higher temperatures, the hohlraum’s actual emission can deviate significantly from a truly blackbody, Lambertian source. At the National Ignition Facility (NIF), Dante provides the best quantification of hohlraum output. Unfortunately, limited diagnostic access coupled with NIF’s natural symmetry does not allow for Dante measurements at more than two angles. As part of the CEPHEUS campaign on NIF, proof-of-principle experiments to better quantify the gold M-band isotropy were conducted. These experiments positioned beryllium/aluminum mirrors at differing angles, offset from the hohlraum. Filtering removes the thermal emission of the hohlraum and the remaining M-band radiation is preferentially absorbed in the aluminum layer. The subsequent hydrodynamic motion is measured via VISAR. Although indirect, this M-band measurement can be made at any angle.
Authors:
 [1] ; ORCiD logo [1] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. AWE Plc., Aldermaston, Reading (United Kingdom)
Publication Date:
Report Number(s):
LA-UR-16-24238; LA-UR-16-21349
Journal ID: ISSN 0034-6748
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 87; Journal Issue: 11; Conference: 2016 High Temperature Plasma Diagnostics Proceedings , Madison, WI (United States), 15 Jun 2016; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; VISAR; Cepheus; M-band; Aluminium; Hohlraum; Beryllium; Mirrors; Foams
OSTI Identifier:
1394969

Lanier, Nicholas Edward, Kline, John L., and Morton, John. Using VISAR to assess the M-band isotropy in hohlraums. United States: N. p., Web. doi:10.1063/1.4962869.
Lanier, Nicholas Edward, Kline, John L., & Morton, John. Using VISAR to assess the M-band isotropy in hohlraums. United States. doi:10.1063/1.4962869.
Lanier, Nicholas Edward, Kline, John L., and Morton, John. 2016. "Using VISAR to assess the M-band isotropy in hohlraums". United States. doi:10.1063/1.4962869. https://www.osti.gov/servlets/purl/1394969.
@article{osti_1394969,
title = {Using VISAR to assess the M-band isotropy in hohlraums},
author = {Lanier, Nicholas Edward and Kline, John L. and Morton, John},
abstractNote = {In laser based radiation flow experiments, drive variability can often overwhelm the physics sensitivity that one seeks to quantify. Hohlraums can help by providing a more symmetrized, Planckian-like source. However, at higher temperatures, the hohlraum’s actual emission can deviate significantly from a truly blackbody, Lambertian source. At the National Ignition Facility (NIF), Dante provides the best quantification of hohlraum output. Unfortunately, limited diagnostic access coupled with NIF’s natural symmetry does not allow for Dante measurements at more than two angles. As part of the CEPHEUS campaign on NIF, proof-of-principle experiments to better quantify the gold M-band isotropy were conducted. These experiments positioned beryllium/aluminum mirrors at differing angles, offset from the hohlraum. Filtering removes the thermal emission of the hohlraum and the remaining M-band radiation is preferentially absorbed in the aluminum layer. The subsequent hydrodynamic motion is measured via VISAR. Although indirect, this M-band measurement can be made at any angle.},
doi = {10.1063/1.4962869},
journal = {Review of Scientific Instruments},
number = 11,
volume = 87,
place = {United States},
year = {2016},
month = {9}
}