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Title: Neutron production and implosion characteristics of a deuterium gas-puff Z pinch

Abstract

Experiments on the Z accelerator with deuterium gas puff implosions have produced up to 3.9x10{sup 13} ({+-}20%) neutrons at 2.34 MeV ({+-}0.10 MeV). Experimentally, the mechanism for generating these neutrons has not been definitively identified through isotropy measurements, but activation diagnostics suggest multiple mechanisms may be responsible. One-, two-, and three-dimensional magnetohydrodynamic (MHD) calculations have indicated that thermonuclear outputs from Z could be expected to be in the (0.3-1.0)x10{sup 14} range. X-ray diagnostics of plasma conditions, fielded to look at dopant materials in the deuterium, have shown that the stagnated deuterium plasma achieved electron temperatures of 2.2 keV and ion densities of 2x10{sup 20} cm{sup -3}, in agreement with the MHD calculations.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2];  [3];  [2];  [2] more »;  [2];  [2];  [2] « less
  1. Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)
  2. (United States)
  3. (United Kingdom)
Publication Date:
OSTI Identifier:
20974841
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 2; Other Information: DOI: 10.1063/1.2446177; (c) 2007 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; ACCELERATORS; DEUTERIUM; ELECTRON TEMPERATURE; IMPLOSIONS; ION DENSITY; ION TEMPERATURE; KEV RANGE; MAGNETOHYDRODYNAMICS; MEV RANGE 01-10; NEUTRONS; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA SIMULATION; THREE-DIMENSIONAL CALCULATIONS; X RADIATION

Citation Formats

Coverdale, C. A., Deeney, C., Velikovich, A. L., Clark, R. W., Chong, Y. K., Davis, J., Chittenden, J., Ruiz, C. L., Cooper, G. W., Nelson, A. J., Franklin, J., LePell, P. D., Apruzese, J. P., Levine, J., Banister, J., Qi, N., Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, Blackett Laboratories, Imperial College, London SW7 2BZ, Sandia National Laboratories, Albuquerque, New Mexico 87123, Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131, Ktech Corporation, Albuquerque, New Mexico 87123, Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, and L-3 Communications/Pulse Sciences Division, San Leandro, CA 94577. Neutron production and implosion characteristics of a deuterium gas-puff Z pinch. United States: N. p., 2007. Web. doi:10.1063/1.2446177.
Coverdale, C. A., Deeney, C., Velikovich, A. L., Clark, R. W., Chong, Y. K., Davis, J., Chittenden, J., Ruiz, C. L., Cooper, G. W., Nelson, A. J., Franklin, J., LePell, P. D., Apruzese, J. P., Levine, J., Banister, J., Qi, N., Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, Blackett Laboratories, Imperial College, London SW7 2BZ, Sandia National Laboratories, Albuquerque, New Mexico 87123, Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131, Ktech Corporation, Albuquerque, New Mexico 87123, Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, & L-3 Communications/Pulse Sciences Division, San Leandro, CA 94577. Neutron production and implosion characteristics of a deuterium gas-puff Z pinch. United States. doi:10.1063/1.2446177.
Coverdale, C. A., Deeney, C., Velikovich, A. L., Clark, R. W., Chong, Y. K., Davis, J., Chittenden, J., Ruiz, C. L., Cooper, G. W., Nelson, A. J., Franklin, J., LePell, P. D., Apruzese, J. P., Levine, J., Banister, J., Qi, N., Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, Blackett Laboratories, Imperial College, London SW7 2BZ, Sandia National Laboratories, Albuquerque, New Mexico 87123, Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131, Ktech Corporation, Albuquerque, New Mexico 87123, Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375, and L-3 Communications/Pulse Sciences Division, San Leandro, CA 94577. Thu . "Neutron production and implosion characteristics of a deuterium gas-puff Z pinch". United States. doi:10.1063/1.2446177.
@article{osti_20974841,
title = {Neutron production and implosion characteristics of a deuterium gas-puff Z pinch},
author = {Coverdale, C. A. and Deeney, C. and Velikovich, A. L. and Clark, R. W. and Chong, Y. K. and Davis, J. and Chittenden, J. and Ruiz, C. L. and Cooper, G. W. and Nelson, A. J. and Franklin, J. and LePell, P. D. and Apruzese, J. P. and Levine, J. and Banister, J. and Qi, N. and Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375 and Blackett Laboratories, Imperial College, London SW7 2BZ and Sandia National Laboratories, Albuquerque, New Mexico 87123 and Chemical and Nuclear Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131 and Ktech Corporation, Albuquerque, New Mexico 87123 and Plasma Physics Division, Naval Research Lab, Washington, D.C. 20375 and L-3 Communications/Pulse Sciences Division, San Leandro, CA 94577},
abstractNote = {Experiments on the Z accelerator with deuterium gas puff implosions have produced up to 3.9x10{sup 13} ({+-}20%) neutrons at 2.34 MeV ({+-}0.10 MeV). Experimentally, the mechanism for generating these neutrons has not been definitively identified through isotropy measurements, but activation diagnostics suggest multiple mechanisms may be responsible. One-, two-, and three-dimensional magnetohydrodynamic (MHD) calculations have indicated that thermonuclear outputs from Z could be expected to be in the (0.3-1.0)x10{sup 14} range. X-ray diagnostics of plasma conditions, fielded to look at dopant materials in the deuterium, have shown that the stagnated deuterium plasma achieved electron temperatures of 2.2 keV and ion densities of 2x10{sup 20} cm{sup -3}, in agreement with the MHD calculations.},
doi = {10.1063/1.2446177},
journal = {Physics of Plasmas},
number = 2,
volume = 14,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • This paper presents the physical characteristics of the z-pinch implosion plasma. Experiments were carried out on a small gas-puff z-pinch plasma device. A three-frame Mach-Zehnder interferometer was developed to measure implosion plasma. Some important physical parameters of plasma implosion process were obtained. At the same time, the soft x-ray energy spectra range from 0.2 {approx} 1.5 keV and the energy spectra of ion beam emitted from the z-pinch plasma were measured.
  • The four-frame high-speed electrooptical camera backed by an automatic image capturing and processing system has been used to investigate the evolution of the gas-puff Z-pinch. The sequence of four images of the pinch continuum radiation (the exposure of each frame was 1 ns, the time separation of frames was 10 or 20 ns) enabled the study of the pinch-forming phase (zipper effect, compression), the stagnation of plasma on the axis, as well as the pinch decay (disintegration, collapsing of the plasma column) and the determination of the velocities of individual processes.
  • An argon annular puff-gas z-pinch has been experimentally investigated during the early phase of the current pulse using a magnetic flux probe and streak interferometry. The current is seen to follow the flared outer edge of the gas jet and to be returned primarily at axial positions z<15 mm by six posts supporting the wire mesh anode. A theoretical estimate of the skin depth agrees with the measured approx.1-cm thickness of the current sheath. The electron to neutral density ratio is determined to be peaked both near the posts and near the cathode.
  • Experiments on the Z accelerator with deuterium gas-puff implosions have produced up to 3.7x10{sup 13} ({+-}20%) neutrons at 2.34 MeV ({+-}0.10 MeV). Although the mechanism for generating these neutrons was not definitively identified, this neutron output is 100 times more than previously observed from neutron-producing experiments at Z. Dopant gases in the deuterium (argon and chlorine) were used to study implosion characteristics and stagnated plasma conditions through x-ray yield measurements and spectroscopy. Magnetohydrodynamic (MHD) calculations have suggested that the dopants improved the neutron output through better plasma compression, which has been studied in experiments increasing the dopant fraction. Scaling thesemore » experiments, and additional MHD calculations, suggest that {approx}5x10{sup 14} deuterium-deuterium (DD) neutrons could be generated at the 26-MA refurbished Z facility.« less
  • We present the first fully kinetic, collisional, and electromagnetic simulations of the complete time evolution of a deuterium gas puff z pinch. Recent experiments with 15-MA current pinches have suggested that the dominant neutron-production mechanism is thermonuclear. We observe distinct differences between the kinetic and magnetohydrodynamic simulations in the pinch evolution with the kinetic simulations producing both thermonuclear and beam-target neutrons. The kinetic approach demonstrated in this Letter represents a viable alternative for performing future plasma physics calculations.