Publications
353 results found
Coverdale CA, Jones B, LePell PD, et al., 2006, Dynamics of copper wire arrays at 1 MA and 20 MA generators, 6th International Conference on Dense Z-Pinches, Publisher: AMER INST PHYSICS, Pages: 45-+, ISSN: 0094-243X
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- Citations: 14
Bland SN, Lebedev SV, Hall GN, et al., 2006, The effect of wire initiation on array dynamics, Dense Z-Pinches, Vol: 808, Pages: 9-14, ISSN: 0094-243X
Bland SN, Lebedev SV, Hall GN, et al., 2006, The effect of wire initiation on array dynamics, Dense Z-Pinches, Vol: 808, Pages: 9-14, ISSN: 0094-243X
Bland SN, Lebedev SV, Hall GN, et al., 2006, The effect of wire initiation on array dynamics, Dense Z-Pinches, Vol: 808, Pages: 9-14, ISSN: 0094-243X
Chittenden JP, Vincent P, Jennings CA, et al., 2006, Hotspot ignition using a Z-pinch precursor plasma in a magneto-inertial ICF scheme, Publisher: American Institute of Physics, Pages: 335-338, ISSN: 0094-243X
Hall GN, Pikuz SA, Shelkovenko TA, et al., 2006, Structure of stagnated plasma in aluminium wire array Z-pinches, Dense Z-Pinches, Vol: 808, Pages: 53-56, ISSN: 0094-243X
Hall GN, Pikuz SA, Shelkovenko TA, et al., 2006, Structure of stagnated plasma in aluminium wire array Z-pinches, Dense Z-Pinches, Vol: 808, Pages: 53-56, ISSN: 0094-243X
Jones B, Deeney C, McKenney JL, et al., 2006, Seeded perturbations in wire array z-pinches, 6th International Conference on Dense Z-Pinches, Publisher: AMER INST PHYSICS, Pages: 61-+, ISSN: 0094-243X
Lebedev SV, Ciardi A, Ampleford DJ, et al., 2005, Production of radiatively cooled hypersonic plasma jets and links to astrophysical jets, 32nd European-Physical-Society Conference on Plasma Physics, Publisher: IOP PUBLISHING LTD, Pages: B465-B479, ISSN: 0741-3335
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- Citations: 54
Jones B, Deeney C, McKenney JL, et al., 2005, Study of three-dimensional structure in wire-array <i>z</i> pinches by controlled seeding of axial modulations in wire radius -: art. no. 225001, PHYSICAL REVIEW LETTERS, Vol: 95, ISSN: 0031-9007
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- Citations: 40
Cuneo ME, Vesey RA, Sinars DB, et al., 2005, Demonstration of radiation pulse shaping with nested-tungsten-wire-array Z pinches for high-yield inertial confinement fusion, PHYSICAL REVIEW LETTERS, Vol: 95, ISSN: 0031-9007
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- Citations: 36
Bland SN, Lebedev SV, Chittenden JP, et al., 2005, Effect of radial-electric-field polarity on wire-array Z-pinch dynamics -: art. no. 135001, PHYSICAL REVIEW LETTERS, Vol: 95, ISSN: 0031-9007
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- Citations: 25
Lebedev SV, Ciardi A, Ampleford DJ, et al., 2005, Magnetic tower outflows from a radial wire array Z-pinch, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 361, Pages: 97-108, ISSN: 0035-8711
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- Citations: 131
Cuneo ME, Sinars DB, Bliss DE, et al., 2005, Direct experimental evidence for current-transfer mode operation of nested tungsten wire arrays at 16-19 MA, PHYSICAL REVIEW LETTERS, Vol: 94, ISSN: 0031-9007
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- Citations: 41
Frank A, Blackman EG, Cunningham A, et al., 2005, A HED laboratory astrophysics testbed comes of age: JET deflection via cross winds, 5th International Conference on High Energy Density Laboratory Astrophysics, Publisher: SPRINGER, Pages: 107-114, ISSN: 0004-640X
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- Citations: 5
Mazarakis MG, Deeney CE, Douglas MR, et al., 2005, Tungsten wire number dependence of the implosion dynamics at the Z-accelerator, PLASMA DEVICES AND OPERATIONS, Vol: 13, Pages: 157-161, ISSN: 1051-9998
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- Citations: 21
Ciardi A, Lebedev SV, Chittenden JP, et al., 2005, Modeling magnetic tower jets in the laboratory, 5th International Conference on High Energy Density Laboratory Astrophysics, Publisher: SPRINGER, Pages: 277-286, ISSN: 0004-640X
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- Citations: 15
Ampleford DJ, Lebedev SV, Ciardi A, et al., 2005, Formation of working surfaces in radiatively cooled laboratory jets, 5th International Conference on High Energy Density Laboratory Astrophysics, Publisher: SPRINGER, Pages: 241-246, ISSN: 0004-640X
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- Citations: 30
Lebedev SV, Ampleford DJ, Bland SN, et al., 2005, Physics of wire array Z-pinch implosions: experiments at Imperial College, 12th International Congress on Plasma Physics (ICPP2004), Publisher: IOP PUBLISHING LTD, Pages: A91-A108, ISSN: 0741-3335
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- Citations: 89
Cuneo ME, Waisman EM, Lebedev SV, et al., 2005, Characteristics and scaling of tungsten-wire-array <i>z</i>-pinch implosion dynamics at 20 MA -: art. no. 046406, PHYSICAL REVIEW E, Vol: 71, ISSN: 1539-3755
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- Citations: 179
Mazarakis MG, Deeney CE, Douglas MR, et al., 2004, Wire number dependence of the implosion dynamics, stagnation and radiation output of tungsten wire arrays at Z, Pages: 696-699
We report results of the experimental campaign which studied the initiation, implosion dynamics and radiation yield of tungsten wire arrays as a function of the wire number. The wire array dimensions and mass were those of interest for the Z-pinch driven ICF program. An optimization study of the X-ray emitted peak power, rise time and FWHM was effectuated by varying the wire number while keeping the total array mass constant and equal to 5.8 mg. The driver utilized is the 20 MA Z accelerator in its usual short pulse mode of 100 ns. We studied single arrays of 20 mm diameter and 1 cm height. The smaller wire number studied was 30 and the largest 600. It appears that 600 is the highest achievable wire number with present day's technology. Radial and axial diagnostics were utilized including crystal monochromatic X-ray backlighter. An optimum wire number of 370 was observed which is very close to the routinely utilized 300 for the ICF program in Sandia. © 2004 D.V. Efremov Scientific Research Institute of Electrophysical Apparatus.
Deeney C, Nash TJ, LePell PD, et al., 2004, High opacity effects in multi-milligram aluminum wire array implosions, ISSN: 0730-9244
High mass aluminum wire array implosions have been performed on Z to provide data on the parameters of the stagnated high opacity plasma. The aluminum wire arrays were composed of 300 wires on a 20-mm diameter with a total mass loading of 6050 μg/cm. The aluminum alloy used, 5056, had 5% Mg by mass. The measured total x-ray emissions had a yield of 1400 kJ and power of 60 TW. The aluminum and magnesium K-shell emissions combined only totaled 100 kJ, with the spectra indicating very strong continua above and below the K-shell recombination edges. The intense continua (30% of the peak line intensities) are strong indications of high opacities, as were the large ratio of Mg to Al lines, and the presence of strong absorption features in the spectra, especially in the lower energy side of the helium-alpha lines, where many of the satellites lie. Spectral analyses have been performed indicating that only a few percent of the initial mass is heated to temperatures that excite K-shell lines. The remaining mass causes significant absorption of the K-shell emissions. These analyses produce a picture of the mass distribution in the stagnated plasma. In this paper, we will present these analyses, along with comparisons to detailed 1-dimensional (1-D) radiation-magneto-hydrodynamic calculations, and 2-D MHD calculations. Many aspects of these implosions may require 3-D calculations in the future.
Jones B, Coverdale C, LePell PD, et al., 2004, Nested stainless steel wire array variations on the Z accelerator, ISSN: 0730-9244
Nested stainless steel wire arrays have been used extensively on Sandia's Z accelerator as a ∼6.7 keV K-shell source (∼35 kJ, ∼8 TW) for radiation effects studies. In this work, we discuss variations on the standard load (2:1 mass and radius ratios, total mass 1 mg/cm, 55 mm outer array diameter), pursued with the dual intent of radiation source optimization and investigation of physics issues that influence the K-shell source performance. Results will be presented from experiments in which the mass was varied by changing the wire number, keeping the 2:1 mass ratio and other parameters fixed. The 1 mg/cm total mass appears to produce near-optimal power, yield, and rise time, though the optimum may lie closer to 0.8 mg/cm. Additional experiments will be discussed in which the geometry of the outer array was kept fixed in the standard 55 mm diameter configuration while inner array radii between 25-75% of that of the outer array were fielded. The inner array mass was chosen to hold the implosion time constant. With > 1 mm interwire gaps for all of these arrays, the inner array is expected to be transparent to the imploding outer array, and thus the effect of varying mass and velocity of the final implosion on K-shell production is studied. In these experiments, the 2:1 radius ratio of the standard load appears to be optimal. Also presented will be observations of non-0D implosion of the outer array, based on data from optical streak camera1, laser shadowgraphy2, Z-Beamlet bent crystal backlighting3, and electrical circuit inductance diagnostics4. The delayed trajectory observed is consistent with an initial ablation phase preceding the implosion, and observations of axially non-uniform ablation and trailing mass will be presented as well. Finally, circuit diagnostics have been used to infer the electrical energy input to the pinch, which can be compared to the x-ray output in order to address energy balance in fast z-pinches. Sandia is a multi-program la
Lebedev SV, Ampleford D, Ciardi A, et al., 2004, Jet deflection via crosswinds: Laboratory astrophysical studies, ASTROPHYSICAL JOURNAL, Vol: 616, Pages: 988-997, ISSN: 0004-637X
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- Citations: 74
Lebedev SV, Ampleford DJ, Bland SN, et al., 2004, Plasma Dynamics in Radial Wire Array Z-Pinches, ISSN: 0730-9244
We describe experiments on the MAGPIE facility (1MA, 250ns) with radial wire array z-pinches, in which the wires form a wheel-spoke configuration. Variation of the global magnetic field and the corresponding J×B force along the wires in this configuration allows studying an effect of the global magnetic field on the ablation rate of the wires. The knowledge of the scaling of the ablation rate is important for interpretation of the dynamics of wire array z-pinch plasma radiation sources. The parameters of the coronal plasma, which is pushed away from the wire cores by the J×B force, were measured using laser interferometry, X-ray and XUV imaging. The complete ablation of the wires near the inner electrode, where the ablation rate is the highest, triggers an axial acceleration of the plasma. This leads to formation of plasma configuration similar to a plasma focus and generation of the X-ray pulse. The results of the experiments with tungsten and aluminium radial wire arrays will be presented.
Lebedev SV, Ampleford DJ, Bland SN, et al., 2004, Wire array Z-pinch experiments at Imperial College, Pages: 730-734
The physics of plasma formation in wire array Z-pinches and effects of the radial redistribution of mass by the precursor plasma flow were studied in experiments on the Magpie generator (1MA, 250ns). Scaling of the ablation rate of the wires with global magnetic field and wire number, and importance of the material left behind by the implosion are discussed.
Lebedev SV, Ampleford DJ, Bland SN, et al., 2004, Implosion dynamics of wire array Z-pinches: experiments at Imperial College, NUCLEAR FUSION, Vol: 44, Pages: S215-S220, ISSN: 0029-5515
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- Citations: 40
Sanford TWL, Nash TJ, Olson RE, et al., 2004, Progress in z-pinch driven dynamic-hohlraums for high-temperature radiation-flow and ICF experiments at Sandia National Laboratories, 31st European-Physical-Society Conference on Plasma Physics, Publisher: IOP PUBLISHING LTD, Pages: B423-B433, ISSN: 0741-3335
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- Citations: 26
Chittenden JP, Lebedev SV, Jennings CA, et al., 2004, X-ray generation mechanisms in three-dimensional simulations of wire array Z-pinches, 31st European-Physical-Society Conference on Plasma Physics, Publisher: IOP PUBLISHING LTD, Pages: B457-B476, ISSN: 0741-3335
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- Citations: 183
Bland SN, Lebedev SV, Chittenden JP, et al., 2004, Use of linear wire array <i>Z</i> pinches to examine plasma dynamics in high magnetic fields, PHYSICS OF PLASMAS, Vol: 11, Pages: 4911-4921, ISSN: 1070-664X
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- Citations: 26
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