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Bright spots in 1 MA X pinches as a function of wire number and material

Proposed for publication in Physics of Plasmas.

Ampleford, David J.; Cuneo, Michael E.; Wenger, D.F.

Bright, intense x-ray sources with extreme plasma parameters (micropinch plasmas) have previously been characterized at 0.1-0.4 MA, but the scaling of such sources at higher current is poorly understood. The x-ray source size and radiation power of 1 MA X pinches were studied as a function of wire material (Al, Ti, Mo, and W) and number (1-, 2-, 8-, 32-, and 64-wire configurations). The smallest bright spots observed were from 32-wire tungsten X pinches, which produced {le} 11-16 {micro}m, {approx}2 J, 1-10 GW sources of 3-5 keV radiation.

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Planar wire array dynamics and radiation scaling at multi-MA levels on the Saturn pulsed power generator

Jones, Brent M.; Cuneo, Michael E.; Ampleford, David J.; Coverdale, Christine A.; Vesey, Roger A.; Jones, Michael

Planar wire arrays are studied at 3-6 MA on the Saturn pulsed power generator as potential drivers of compact hohlraums for inertial confinement fusion studies. Comparison with zero-dimensional modeling suggests that there is significant trailing mass. The modeled energy coupled from the generator cannot generally explain the energy in the main x-ray pulse. Preliminary comparison at 1-6 MA indicates sub-quadratic scaling of x-ray power in a manner similar to compact cylindrical wire arrays. Time-resolved pinhole images are used to study the implosion dynamics.

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Lower bounds for the kinetic energy and resistance of wire array Z pinches on the Z pulsed-power accelerator

Physics of Plasmas

Waisman, Eduardo M.; Cuneo, Michael E.; Lemke, Raymond W.; Sinars, Daniel; 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.

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Fill-Tube-Induced Mass Perturbations on X-Ray-Driven, Ignition-Scale, Inertial-Confinement-Fusion Capsule Shells and the Implications for Ignition Experiments

Physical Review Letters

Bennett, Guy R.; Keller, Keith L.; Mulville, Thomas D.; Peterson, K.J.; Sinars, Daniel; Smith, Ian C.; Vesey, Roger A.; Herrmann, Mark H.; Christenson, Peggy J.; Cuneo, Michael E.

We present on the first inertial-confinement-fusion ignition facility, the target capsule will be DT filled through a long, narrow tube inserted into the shell. μg-scale shell perturbations Δm' arising from multiple, 10–50 μm-diameter, hollow SiO2 tubes on x-ray-driven, ignition-scale, 1-mg capsules have been measured on a subignition device. Finally, simulations compare well with observation, whence it is corroborated that Δm' arises from early x-ray shadowing by the tube rather than tube mass coupling to the shell, and inferred that 10–20 μm tubes will negligibly affect fusion yield on a full-ignition facility.

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Results 301–325 of 392
Results 301–325 of 392