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Title: Comparative properties of the interior and blowoff plasmas in a dynamic hohlraum

Abstract

A Dynamic Hohlraum (DH) is formed when arrays of tungsten wires driven by a high-current pulse implode and compress a cylindrical foam target. The resulting radiation is confined by the wire plasma and forms an intense, ~200–250 eV Planckian x-ray source. The internal radiation can be used for indirect drive inertial confinement fusion. The radiation emitted from the ends can be employed for radiation flow and material interaction studies. This external radiation is accompanied by an expanding blowoff plasma. In this paper, we have diagnosed this blowoff plasma using K-shell spectra of Mg tracer layers placed at the ends of some of the Dynamic Hohlraum targets. A similar diagnosis of the interior hohlraum has been carried out using Al and Mg tracers placed at 2mm depth from the ends. It is found that the blowoff plasma is about 20–25% as dense as that of the interior hohlraum, and that its presence does not significantly affect the outward flow of the nearly Planckian radiation field generated in the hohlraum interior. Finally, however, the electron temperature of the blowoff region, at ~120 eV, is only about half that of the interior hohlraum plasma.

Authors:
 [1];  [1];  [1];  [2];  [2];  [2];  [3]
  1. Naval Research Lab. (NRL), Washington, DC (United States). Plasma Physics Division
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1427013
Report Number(s):
SAND2007-0240J
Journal ID: ISSN 1070-664X; 638691
Grant/Contract Number:
AC04-94AL85000
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 14; Journal Issue: 4; 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; materials; disperse systems; metals; alkaline earth metals; Hohlraum; metallurgy; pure metals; transition metals; ionospheric physics; carbon

Citation Formats

Apruzese, J. P., Clark, R. W., Davis, J., Sanford, T. W. L., Nash, T. J., Mock, R. C., and Peterson, D. L. Comparative properties of the interior and blowoff plasmas in a dynamic hohlraum. United States: N. p., 2007. Web. doi:10.1063/1.2718907.
Apruzese, J. P., Clark, R. W., Davis, J., Sanford, T. W. L., Nash, T. J., Mock, R. C., & Peterson, D. L. Comparative properties of the interior and blowoff plasmas in a dynamic hohlraum. United States. doi:10.1063/1.2718907.
Apruzese, J. P., Clark, R. W., Davis, J., Sanford, T. W. L., Nash, T. J., Mock, R. C., and Peterson, D. L. Fri . "Comparative properties of the interior and blowoff plasmas in a dynamic hohlraum". United States. doi:10.1063/1.2718907. https://www.osti.gov/servlets/purl/1427013.
@article{osti_1427013,
title = {Comparative properties of the interior and blowoff plasmas in a dynamic hohlraum},
author = {Apruzese, J. P. and Clark, R. W. and Davis, J. and Sanford, T. W. L. and Nash, T. J. and Mock, R. C. and Peterson, D. L.},
abstractNote = {A Dynamic Hohlraum (DH) is formed when arrays of tungsten wires driven by a high-current pulse implode and compress a cylindrical foam target. The resulting radiation is confined by the wire plasma and forms an intense, ~200–250 eV Planckian x-ray source. The internal radiation can be used for indirect drive inertial confinement fusion. The radiation emitted from the ends can be employed for radiation flow and material interaction studies. This external radiation is accompanied by an expanding blowoff plasma. In this paper, we have diagnosed this blowoff plasma using K-shell spectra of Mg tracer layers placed at the ends of some of the Dynamic Hohlraum targets. A similar diagnosis of the interior hohlraum has been carried out using Al and Mg tracers placed at 2mm depth from the ends. It is found that the blowoff plasma is about 20–25% as dense as that of the interior hohlraum, and that its presence does not significantly affect the outward flow of the nearly Planckian radiation field generated in the hohlraum interior. Finally, however, the electron temperature of the blowoff region, at ~120 eV, is only about half that of the interior hohlraum plasma.},
doi = {10.1063/1.2718907},
journal = {Physics of Plasmas},
number = 4,
volume = 14,
place = {United States},
year = {Fri Apr 20 00:00:00 EDT 2007},
month = {Fri Apr 20 00:00:00 EDT 2007}
}

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  • A Dynamic Hohlraum (DH) is formed when arrays of tungsten wires driven by a high-current pulse implode and compress a cylindrical foam target. The resulting radiation is confined by the wire plasma and forms an intense, {approx}200-250 eV Planckian x-ray source. The internal radiation can be used for indirect drive inertial confinement fusion. The radiation emitted from the ends can be employed for radiation flow and material interaction studies. This external radiation is accompanied by an expanding blowoff plasma. We have diagnosed this blowoff plasma using K-shell spectra of Mg tracer layers placed at the ends of some of themore » Dynamic Hohlraum targets. A similar diagnosis of the interior hohlraum has been carried out using Al and Mg tracers placed at 2 mm depth from the ends. It is found that the blowoff plasma is about 20-25% as dense as that of the interior hohlraum, and that its presence does not significantly affect the outward flow of the nearly Planckian radiation field generated in the hohlraum interior. However, the electron temperature of the blowoff region, at {approx}120 eV, is only about half that of the interior hohlraum plasma.« less
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  • A complete system is described for the measurement of the distribution of energy emanating from laser-produced plasmas in the form of (1) plasma blowoff (ions, electrons, neutral particles, and x rays), and (2) scattered laser light. The detectors consist of small modules containing two differential calorimeters in one package, one for each form of energy. Modular autozeroing amplifiers enable the slowly varying signals to be measured by computer with the aid of CAMAC analog to digital converters. The computer is also capable of absolutely calibrating the units in situ. The programs used to record and display the data, and tomore » calculate the fraction of laser energy absorbed, are described.« less