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Title: Structure of the dense cores and ablation plasmas in the initiation phase of tungsten wire-array Z pinches

Abstract

The early stages of tungsten (W) wire-array Z-pinch implosions have been studied using two-frame point projection x-ray backlighting on the 1 MA COBRA pulsed power generator [J. D. Douglass, J. B. Greenly, D. A. Hammer, and B. R. Kusse, in Proceedings of the 15th IEEE International Pulsed Power Conference, Monterey, 2005 (to be published)]. X-pinch backlighter images with subnanosecond time resolution and 4-10 {mu}m spatial resolution have been obtained of individual W exploding wires in 8-wire arrays that show evolution of wire-core and coronal plasma structures. The timing of the X-pinch x-ray bursts relative to the Z-pinch initiation time was adjusted over a 50 ns time interval by varying the X-pinch mass per unit length. Wire-cores seen in two images separated in view by 120 deg. show that the expansion is remarkably azimuthally symmetric. A strong correlation is observed between the structure on the dense exploding wire-cores and the structure of the {>=}10{sup 18}/cm{sup 3} ablation plasma being drawn from radial prominences. Plasma ablation velocity was estimated to have a lower bound of 24 km/s. The wire-core expansion rate was found to be approximately constant with time over the interval 50-100 ns after the start of the current pulse. Finally,more » micron-scale axial gaps, seen as early as 70 ns into the current pulse and persisting from that time, were observed along the wire-core.« less

Authors:
; ;  [1]; ;  [1];  [2]; ;  [3]
  1. Laboratory of Plasma Studies, 439 Rhodes Hall, Cornell University, Ithaca, New York 14853 (United States)
  2. (Russian Federation)
  3. Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)
Publication Date:
OSTI Identifier:
20960109
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 1; Other Information: DOI: 10.1063/1.2431633; (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; ABLATION; EXPANSION; EXPLODING WIRES; IMAGES; IMPLOSIONS; LENGTH; PLASMA; SPATIAL RESOLUTION; TIME RESOLUTION; TUNGSTEN; X RADIATION; X-RAY SOURCES

Citation Formats

Douglass, J. D., Hammer, D. A., McBride, R. D., Pikuz, S. A., Shelkovenko, T. A., P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924, Bland, S. N., and Bott, S. C.. Structure of the dense cores and ablation plasmas in the initiation phase of tungsten wire-array Z pinches. United States: N. p., 2007. Web. doi:10.1063/1.2431633.
Douglass, J. D., Hammer, D. A., McBride, R. D., Pikuz, S. A., Shelkovenko, T. A., P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924, Bland, S. N., & Bott, S. C.. Structure of the dense cores and ablation plasmas in the initiation phase of tungsten wire-array Z pinches. United States. doi:10.1063/1.2431633.
Douglass, J. D., Hammer, D. A., McBride, R. D., Pikuz, S. A., Shelkovenko, T. A., P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924, Bland, S. N., and Bott, S. C.. Mon . "Structure of the dense cores and ablation plasmas in the initiation phase of tungsten wire-array Z pinches". United States. doi:10.1063/1.2431633.
@article{osti_20960109,
title = {Structure of the dense cores and ablation plasmas in the initiation phase of tungsten wire-array Z pinches},
author = {Douglass, J. D. and Hammer, D. A. and McBride, R. D. and Pikuz, S. A. and Shelkovenko, T. A. and P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924 and Bland, S. N. and Bott, S. C.},
abstractNote = {The early stages of tungsten (W) wire-array Z-pinch implosions have been studied using two-frame point projection x-ray backlighting on the 1 MA COBRA pulsed power generator [J. D. Douglass, J. B. Greenly, D. A. Hammer, and B. R. Kusse, in Proceedings of the 15th IEEE International Pulsed Power Conference, Monterey, 2005 (to be published)]. X-pinch backlighter images with subnanosecond time resolution and 4-10 {mu}m spatial resolution have been obtained of individual W exploding wires in 8-wire arrays that show evolution of wire-core and coronal plasma structures. The timing of the X-pinch x-ray bursts relative to the Z-pinch initiation time was adjusted over a 50 ns time interval by varying the X-pinch mass per unit length. Wire-cores seen in two images separated in view by 120 deg. show that the expansion is remarkably azimuthally symmetric. A strong correlation is observed between the structure on the dense exploding wire-cores and the structure of the {>=}10{sup 18}/cm{sup 3} ablation plasma being drawn from radial prominences. Plasma ablation velocity was estimated to have a lower bound of 24 km/s. The wire-core expansion rate was found to be approximately constant with time over the interval 50-100 ns after the start of the current pulse. Finally, micron-scale axial gaps, seen as early as 70 ns into the current pulse and persisting from that time, were observed along the wire-core.},
doi = {10.1063/1.2431633},
journal = {Physics of Plasmas},
number = 1,
volume = 14,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}