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R. Davis,
B.V. Weber,
J.P. Apruzese,
J.W. Thornhill,
A. Velikovich,
M. Krishnan, P. Coleman,
H. Sze,
J. Levine,
Y. Maron,
I. Vitkovitsky
[show abstract]
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ABSTRACT: The Decade half X-ray radiation simulator will combine the outputs of eight synchronized modules to produce a current of up to 13 MA delivered to a short circuit load in /spl sim/300 ns. Decade is located within the Decade Radiation Test Facility (DRTF) at the Arnold Engineering Development Center, Tullahoma, TN. Decade's output will be used for nuclear weapons effects testing; the DRTF will reach initial operational capability (IOC) in 2007. DoD's X-ray radiation simulator R&D program is focused on maximizing 3.1 keV X-ray fluence from Decade's argon z-pinch. Electric current risetime will be approximately a factor of 3 longer than typically used to drive plasma radiation source (PRS) loads. Scaling to longer current risetime is advantageous in terms of reduced driver cost and complexity. The use of longer pulse drivers, however, requires an increase in the initial diameter of the z-pinch gas puff. The unique challenge is to extend the success with 100 ns current risetime simulators into the realm of the 300 ns current risetime of Decade. As the diameter is increased, increased asymmetry and instability can limit the ability of the load to produce K-shell radiation efficiently. These effects were largely un-quantified until technical investigations were conducted under the auspices of the simulator R&D program. This paper discusses progress, activities and issues in developing the large diameter z-pinch for Decade.
Pulsed Power Conference, 2003. Digest of Technical Papers. PPC-2003. 14th IEEE International; 07/2003
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D. MOSHER ,
B.V. WEBER ,
B. MOOSMAN ,
R.J. COMMISSO , P. COLEMAN ,
E. WAISMAN ,
H. SZE ,
Y. SONG ,
D. PARKS ,
P. STEEN ,
J. LEVINE ,
B. FAILOR ,
A. FISHER
[show abstract]
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ABSTRACT: High-sensitivity interferometry measurements of initial density
distributions are reviewed for a wide range of gas-puff nozzles
used in plasma radiation source (PRS) z-pinch experiments.
Accurate gas distributions are required for determining
experimental load parameters, modeling implosion dynamics,
understanding the radiation properties of the stagnated pinch,
and for predicting PRS performance in future experiments. For
a number of these nozzles, a simple ballistic-gas-flow model
(BFM) has been used to provide good physics-based analytic fits
to the measured r, z density distributions.
These BFM fits provide a convenient means to smoothly interpolate
radial density distributions between discrete axial measurement
locations for finer-zoned two-dimensional MHD calculations, and
can be used to determine how changes in nozzle parameters and
load geometry might alter implosion dynamics and radiation
performance. These measurement and analysis techniques are
demonstrated for a nested-shell nozzle used in Double Eagle
and Saturn experiments. For this nozzle, the analysis suggests
load modifications that may increase the K-shell yield.
Laser and Particle Beams 09/2001; 19(04):579 - 595. · 1.62 Impact Factor
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ABSTRACT: Summary form only given, as follows. The advent of nested wire arrays has enabled far higher quality and high power Z-pinch implosions but questions have been raised on the exact mechanisms by which nested arrays improve the implosion dynamics. In a series of experiments on the Saturn generator, we have imploded high and low wire number nested arrays. By using either pure aluminum (Al 1100) or Al:Mg alloy (Al 5056) in the inner or outer arrays, we can perform tracer spectroscopy. Tracer spectroscopy has been an important diagnostic in laser-plasma interactions and there have been some very successful applications to Z-pinches including coated wires or doped gas puffs by Sze, et al.(2000). In these recent nested array experiments, we show that the wire number does effect the degree of mixing that occurs between the inner and outer. Analyses indicate that for low-wire number case (28 onto 14 wires) the mass of the outer forms the hot emitting region on the stagnated pinch. This is contrary to results from gas puffs. We present the comparison of the low- and high-wire number arrays
Pulsed Power Plasma Science, 2001. IEEE Conference Record - Abstracts; 02/2001
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Y. Song, P. Coleman,
B. H. Failor,
A. Fisher,
R. Ingermanson,
J. S. Levine,
H. Sze,
E. Waisman,
R. J. Commisso,
T. Cochran,
J. Davis,
B. Moosman,
A. L. Velikovich,
B. V. Weber,
D. Bell,
R. Schneider
[show abstract]
[hide abstract]
ABSTRACT: We have developed a dual-plenum gas valve coupled to a double shell nozzle for the generation of “shell-on-shell” gas loads in z-pinch plasma radiation source experiments. The gas density profiles of the nozzles have been characterized with laser interferometry. This valve/nozzle combination has been successfully fielded on the Double-EAGLE and Saturn pulsed-power generators. The design and characterization of the shell-on-shell valve/nozzle are presented in this article. © 2000 American Institute of Physics.
Review of Scientific Instruments 07/2000; 71(8):3080-3084. · 1.37 Impact Factor
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C. Deeney,
C.A. Coverdale,
M.R. Douglas,
J.P. Apruzese,
J.W. Thornhill,
K.G. Whitney,
J Davis,
H. Sze,
B. Failor, P. Coleman,
R Schneider
[show abstract]
[hide abstract]
ABSTRACT: Summary form only given. The optimization and dynamics of aluminum wire arrays, using Al 5056 alloys that contain 5% Mg, have been studied at implosion times from 130 to 200 ns on the Saturn pulsed power generator. In this paper, we will present the spectral analyses and compare them with the measured trends in yield
Plasma Science, 2000. ICOPS 2000. IEEE Conference Record - Abstracts. The 27th IEEE International Conference on; 02/2000
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C.A. Coverdale,
C. Deeney,
M.R. Douglas,
P.D. LePell,
H. Sze,
B. Failor, P. Coleman,
K.G. Whitney,
J.W. Thornhill,
J.P. Apruzese,
J Davis,
R Schneider
[show abstract]
[hide abstract]
ABSTRACT: Summary form only given, as follows. Experiments to study aluminum K-shell emissions from long implosion time Z-pinches have been performed on the 8-MA Saturn accelerator. The experiments, designed to investigate the effects of initial load diameter and wire number on the Al K-shell radiation, were motivated in part by the need to understand the consequences of longer implosion time Z-pinch drivers. Typically, most pulsed power Z-pinch drivers have implosion times of 50-100 ns; Saturn in the long pulse mode can produce implosion times of 130-200 ns. In the wire number experiments, the initial load diameter was held constant at 30 mm, the mass was fixed near 620 μg/cm (for an implosion time near 165 ns), and the number of wires in the array was varied from 32 to 282. Yields greater than 60 kJ were measured, and variations in the FWHM and risetime clearly show the interwire gap spacing where wire merger occurs. In a separate series of experiments, the initial load diameter was varied from 32 mm to 50 mm, with the implosion time also fixed near 165 ns. Al K-shell yields up to 60 kJ were measured, with the largest diameter loads producing the highest yields. These results will he compared to calculations, Haines' wire merger model, and with short implosion time Al results on Saturn
Plasma Science, 2000. ICOPS 2000. IEEE Conference Record - Abstracts. The 27th IEEE International Conference on; 02/2000
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J. Levine, P. Coleman,
B. Failor,
D. Kortbawi,
D. LePell,
H. Murphy,
J. Riordan,
I. Roth,
L. Schlitt,
P. Sincerny, [......],
A. Fisher,
B. Moosman,
D. Mosher,
S. Stephanakis,
J. Thornhill,
B. Weber,
R Schneider,
P. Spence,
E. Yadlowsky,
M. Krishnan
[show abstract]
[hide abstract]
ABSTRACT: We have created large diameter, long implosion time, PRS loads that produce a stable pinch and a narrow X-ray pulse. Operation scaled successfully with current from 2 MA on DM2 to 6 MA on Saturn. The K-shell yields are comparable to those produced by short-pulse operation at a similar current. This approach, therefore, allows substantial savings to be realized in the pulsed-power driver cost, complexity and risk
High-Power Particle Beams, 1998. BEAMS '98. Proceedings of the 12th International Conference on; 02/1998
