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Title: Diagnosing Dynamic Hohlraums With K-Shell Spectroscopy of Embedded Tracer Layers

Abstract

Diagnostic tracer layers of Al and/or Mg have been embedded in Dynamic Hohlraum targets which are imploded on Sandia National Laboratories' Z generator by surrounding them with nested arrays of tungsten wires. The K-shell lines of these elements are observed, usually in absorption, in both time-resolved and time-integrated spectra. The radiation physics of line formation in this environment is well understood and captured with a detailed model. A {chi}2 fit to the measured line intensities is used in conjunction with the model to determine the hohlraums' intrinsic properties. Among other features, our analyses find no evidence of intrinsic top-bottom asymmetry in the Dynamic Hohlraums.

Authors:
; ; ; ; ; ; ;  [1];  [2];  [2]
  1. Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20729275
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 808; Journal Issue: 1; Conference: 6. international conference on dense Z-pinches, Oxford (United Kingdom), 25-28 Jul 2005; Other Information: DOI: 10.1063/1.2159377; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION; ASYMMETRY; EXPLODING WIRES; K SHELL; LAYERS; LONGITUDINAL PINCH; PLASMA DIAGNOSTICS; SANDIA NATIONAL LABORATORIES; TIME RESOLUTION; TUNGSTEN; X RADIATION; X-RAY SPECTROSCOPY

Citation Formats

Apruzese, J.P., Clark, R.W., Kepple, P.C., Davis, J., Sanford, T.W.L., Nash, T.J., Mock, R.C., Peterson, D.L., Sandia National Laboratories, Albuquerque NM 87185, and Los Alamos National Laboratory, Los Alamos NM 87545. Diagnosing Dynamic Hohlraums With K-Shell Spectroscopy of Embedded Tracer Layers. United States: N. p., 2006. Web. doi:10.1063/1.2159377.
Apruzese, J.P., Clark, R.W., Kepple, P.C., Davis, J., Sanford, T.W.L., Nash, T.J., Mock, R.C., Peterson, D.L., Sandia National Laboratories, Albuquerque NM 87185, & Los Alamos National Laboratory, Los Alamos NM 87545. Diagnosing Dynamic Hohlraums With K-Shell Spectroscopy of Embedded Tracer Layers. United States. doi:10.1063/1.2159377.
Apruzese, J.P., Clark, R.W., Kepple, P.C., Davis, J., Sanford, T.W.L., Nash, T.J., Mock, R.C., Peterson, D.L., Sandia National Laboratories, Albuquerque NM 87185, and Los Alamos National Laboratory, Los Alamos NM 87545. Thu . "Diagnosing Dynamic Hohlraums With K-Shell Spectroscopy of Embedded Tracer Layers". United States. doi:10.1063/1.2159377.
@article{osti_20729275,
title = {Diagnosing Dynamic Hohlraums With K-Shell Spectroscopy of Embedded Tracer Layers},
author = {Apruzese, J.P. and Clark, R.W. and Kepple, P.C. and Davis, J. and Sanford, T.W.L. and Nash, T.J. and Mock, R.C. and Peterson, D.L. and Sandia National Laboratories, Albuquerque NM 87185 and Los Alamos National Laboratory, Los Alamos NM 87545},
abstractNote = {Diagnostic tracer layers of Al and/or Mg have been embedded in Dynamic Hohlraum targets which are imploded on Sandia National Laboratories' Z generator by surrounding them with nested arrays of tungsten wires. The K-shell lines of these elements are observed, usually in absorption, in both time-resolved and time-integrated spectra. The radiation physics of line formation in this environment is well understood and captured with a detailed model. A {chi}2 fit to the measured line intensities is used in conjunction with the model to determine the hohlraums' intrinsic properties. Among other features, our analyses find no evidence of intrinsic top-bottom asymmetry in the Dynamic Hohlraums.},
doi = {10.1063/1.2159377},
journal = {AIP Conference Proceedings},
number = 1,
volume = 808,
place = {United States},
year = {Thu Jan 05 00:00:00 EST 2006},
month = {Thu Jan 05 00:00:00 EST 2006}
}
  • Diagnostic tracer layers of Al and/or Mg have been embedded in Dynamic Hohlraum targets which are imploded on Sandia National Laboratories Z generator by surrounding them with nested arrays of tungsten wires. The K-shell lines of these elements are observed, usually in absorption, in both time-resolved and time-integrated spectra. The radiation physics of line formation in this environment is well understood and captured with a detailed model. A {chi}{sup 2} fit to the measured line intensities is used in conjunction with the model to determine the hohlraums intrinsic properties. Among other features, our analyses find no evidence of intrinsic top-bottommore » asymmetry in the Dynamic Hohlraums.« less
  • In recent dynamic hohlraum experiments on the Z facility, Al and MgF{sub 2} tracer layers were embedded in cylindrical CH{sub 2} foam targets to provide K-shell lines in the keV spectral region for diagnosing the conditions of the interior hohlraum plasma. The position of the tracers was varied: sometimes they were placed 2 mm from the ends of the foam cylinder and sometimes at the ends of the cylinder. Also varied was the composition of the tracers in the sense that pure Al layers, pure MgF{sub 2} layers, or mixtures of the elements were employed on various shots. Time-resolved K-shellmore » spectra of both Al and Mg show mostly absorption lines. These data can be analyzed with detailed configuration atomic models of carbon, aluminum, and magnesium in which spectra are calculated by solving the radiation transport equation for as many as 4100 frequencies. We report results from shot Z1022 to illustrate the basic radiation physics and the capabilities as well as limitations of this diagnostic method.« less
  • In recent dynamic hohlraum experiments on the Z facility, Al and MgF{sub 2} tracer layers were embedded in cylindrical CH{sub 2} foam targets to provide K-shell lines in the keV spectral region for diagnosing the conditions of the interior hohlraum plasma. The position of the tracers was varied: sometimes they were placed 2 mm from the ends of the foam cylinder and sometimes at the ends of the cylinder. Also varied was the composition of the tracers in the sense that pure Al layers, pure MgF{sub 2} layers, or mixtures of the elements were employed on various shots. Time-resolved K-shellmore » spectra of both Al and Mg show mostly absorption lines. These data can be analyzed with detailed configuration atomic models of carbon, aluminum, and magnesium in which spectra are calculated by solving the radiation transport equation for as many as 4100 frequencies. We report results from shot Z1022 to illustrate the basic radiation physics and the capabilities as well as limitations of this diagnostic method.« less
  • A dynamic Hohlraum (DH) is formed when arrays of tungsten wires driven by a high current pulse implode upon a cylindrical foam target. At impact, the wire plasma launches a radiating shock in the foam and confines the radiation. This sequence of events forms an intense, {approx}200-250 eV Planckian x-ray source which is a prime candidate for indirect drive inertial confinement fusion. In recent DH experiments on the 20 MA Z facility, Al and MgF{sub 2} tracer layers were embedded in the cylindrical foam targets to provide K-shell lines in the keV spectral region for diagnosing the conditions of themore » interior Hohlraum plasma. Time-resolved K-shell spectra of both Al and Mg show mostly absorption lines. These data can be understood and quantitatively analyzed with detailed atomic and radiation transport models. The analyses show no evidence of intrinsic differences in the properties of the tops and bottoms of the Hohlraums. The interiors of the cylindrical Hohlraums are found to be hotter than the ends.« less