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Struve, Kenneth W. ; Lemke, Raymond W. ; Savage, Mark E.
In addressing the issue of the determining the hazard categorization of the Z Accelerator of doing Special Nuclear Material (SNM) experiments the question arose as to whether the machine could be fired with its central vacuum chamber open, thus providing a path for airborne release of SNM materials. In this report we summarize calculations that show that we could only expect a maximum current of 460 kA into such a load in a long-pulse mode, which will be used for the SNM experiments, and 750 kA in a short-pulse mode, which is not useful for these experiments. We also investigated the effect of the current for both cases and found that for neither case is the current high enough to either melt or vaporize these loads, with a melt threshold of 1.6 MA. Therefore, a necessary condition to melt, vaporize, or otherwise disperse SNM material is that a vacuum must exist in the Z vacuum chamber. Thus the vacuum chamber serves as a passive feature that prevents any airborne release during the shot, regardless of whatever containment may be in place.
Lemke, Raymond W. ; Knudson, Marcus D. ; Davis, Jean-Paul D.
Haill, Thomas A. ; Lemke, Raymond W. ; Root, Seth R.
Jennings, Christopher A. ; Sinars, Daniel S. ; Cuneo, M.E. ; Lemke, Raymond W. ; Ampleford, David A. ; Stygar, William A. ; Jones, Michael J. ; Bennett, Guy R. ; Savage, Mark E. ; LeChien, Keith R.
Yu, Edmund Y. ; Lemke, Raymond W. ; Hanshaw, Heath L. ; Jones, Brent M. ; Haill, Thomas A. ; Flicker, Dawn G.
Langston, William L. ; Coats, Rebecca S. ; Knudson, Marcus D. ; Lemke, Raymond W. ; Davis, Jean-Paul D. ; Pointon, Timothy D.
Jennings, Christopher A. ; Sinars, Daniel S. ; Cuneo, M.E. ; Lemke, Raymond W. ; Ampleford, David A. ; Stygar, William A. ; Jones, Michael J. ; Bennett, Guy R. ; Savage, Mark E. ; LeChien, Keith R.
Lemke, Raymond W.
Jones, Michael J. ; Cuneo, M.E. ; Lemke, Raymond W. ; Ampleford, David A. ; Jennings, Christopher A.
Physics of Plasmas
Yu, Edmund Y. ; Cuneo, M.E. ; Desjarlais, Michael P. ; Lemke, Raymond W. ; Sinars, Daniel S. ; Haill, Thomas A. ; Waisman, E.M.; Bennett, G.R.; Jennings, C.A.; Mehlhorn, T.A.; Brunner, T.A.; Hanshaw, H.L.; Porter, J.L.; Stygar, W.A.; Rudakov, L.I.
The implosion phase of a wire-array Z pinch is investigated using three-dimensional (3D) simulations, which model the mass ablation phase and its associated axial instability using a mass injection boundary condition. The physical mechanisms driving the trailing mass network are explored, and it is found that in 3D the current paths though the trailing mass can reduce bubble growth on the imploding plasma sheath, relative to the 2D (r,z) equivalent. Comparison between the simulations and a high quality set of experimental radiographs is presented. © 2008 American Institute of Physics.
Lemke, Raymond W. ; Sinars, Daniel S. ; Yu, Edmund Y. ; Haill, Thomas A. ; Brunner, Thomas A. ; Hanshaw, Heath L. ; Cuneo, M.E. ; Desjarlais, Michael P. ; Mehlhorn, Thomas A.
Physics of Plasmas
Waisman, Eduardo M.; Cuneo, M.E. ; Lemke, Raymond W. ; Sinars, Daniel S. ; Stygar, William A.
Approximate lower bounds for the kinetic energy and magnetic flux dissipation for tungsten wire arrays on the Z pulsed-power accelerator at Sandia National Laboratories [R. B. Spielman, Phys. Plasmas 5, 2105 (1998)] are obtained. A procedure, extending previous work determining pinch inductance as a function of time [E. M. Waisman, Phys. Plasmas 11, 2009 (2004)], is introduced and applied to electrical and x-ray energy measurements. It employs the pinch energy balance to determine lower bounds for the plasma kinetic energy just before the main pinch reaches the axis and for the magnetic flux dissipation during stagnation. From the lower bound for the dissipated flux, a lower bound for pinch resistance after x-ray peak power is estimated. The results of applying the introduced energy balance procedure to selected tungsten wire array implosions on Z are given. It is believed that this is the first time that a measure of wire array Z-pinch resistance at stagnation is obtained purely from data analysis without recourse to specific assumptions on the plasma motion. © 2008 American Institute of Physics.
Cuneo, M.E. ; Jones, Brent M. ; Jones, Michael J. ; Lemke, Raymond W. ; Sinars, Daniel S. ; Stygar, William A.
Robinson, Allen C. ; Kaye, Ronald J. ; Lamppa, Derek C. ; Lemke, Raymond W. ; Garasi, Christopher J.
Defense Science Quarterly
Sweeney, Mary A. ; Knudson, Marcus D. ; Davis, Jean-Paul D. ; LeChien, Keith R. ; Savage, Mark E. ; Lemke, Raymond W. ; Stygar, William A. ; Donovan, Guy L.
Lopez, Mike R. ; Jones, Michael J. ; Cuneo, M.E. ; Lemke, Raymond W.
Lemke, Raymond W. ; Haill, Thomas A. ; Yu, Edmund Y. ; Sinars, Daniel S. ; Hanshaw, Heath L. ; Brunner, Thomas A. ; Cuneo, M.E. ; Desjarlais, Michael P. ; Mehlhorn, Thomas A.
Desjarlais, Michael P. ; Dolan, Daniel H. ; Lemke, Raymond W.
Peterson, Kyle J. ; Lemke, Raymond W.
Sinars, Daniel S. ; Wenger, D.F. ; Cuneo, M.E. ; Lemke, Raymond W. ; Stygar, William A. ; Jones, Brent M. ; Jones, Michael J. ; Yu, Edmund Y.
Cuneo, M.E. ; Sinars, Daniel S. ; Stygar, William A. ; Lemke, Raymond W.
Weirs, Vincent G. ; Lemke, Raymond W. ; Robinson, Allen C. ; Ober, Curtis C. ; Banks, Jeffrey W. ; Love, Edward L. ; Scovazzi, Guglielmo S. ; Shadid, John N. ; Hanshaw, Heath L.
Hanshaw, Heath L. ; Lemke, Raymond W. ; Yu, Edmund Y. ; Desjarlais, Michael P. ; Mehlhorn, Thomas A.
Knudson, Marcus D. ; Desjarlais, Michael P. ; Lemke, Raymond W.
Plasma Physics and Controlled Fusion
Bailey, James E. ; Chandler, Gordon A. ; Leeper, Ramon J. ; Mehlhorn, Thomas A. ; Peterson, Kyle J. ; Lemke, Raymond W. ; Slutz, Stephen A. ; Ruiz, Carlos L.
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