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Z-Pinch Generated X-Rays in Static-Wall Hohlraum Geometry Demonstrate Potential for Indirect-Drive ICF Studies

Description: Hohlraums of full ignition scale (6-mm diameter by 7-mm length) have been heated by x-rays from a z-pinch magnet on Z to a variety of temperatures and pulse shapes which can be used to simulate the early phases of the National Ignition Facility (NIF) temperature drive. The pulse shape is varied by changing the on-axis target of the z pinch in a static-wall-hohlraum geometry. A 2-{micro}m-thick walled Cu cylindrical target of 8-mm diameter filled with 10 mg/cm{sup 3} CH, for example, produces fo… more
Date: November 1, 1999
Creator: Bowers, Richard; Chandler, Gordon A.; Hebron, David E.; Leeper, Ramon J.; Matuslka, Walter; Mock, Raymond Cecil et al.
Partner: UNT Libraries Government Documents Department
open access

The Prospects for High-Yield ICF with a Z-Pinch Driven Dynamic Hohlraum

Description: Recent success with the Sandia Z machine has renewed interest in utilizing fast z-pinenes for ICF. One promising concept places the ICF capsule internal to the imploding z-pinch. At machine parameters relevant to achieving high yield, the imploding z-pinch mass has sufficient opacity to trap radiation giving rise to a dynamic hohlraum. The concept utilizes a 12 MJ, 54 MA z-pinch driver producing a capsule drive temperature exceeding 300 eV to realize a 550 MJ thermonuclear yield. They present t… more
Date: September 7, 1999
Creator: Chandler, Gordon A.; Chrien, R.; Cooper, Gary Wayne; Derzon, Mark S.; Douglas, Melissa R.; Hebron, David E. et al.
Partner: UNT Libraries Government Documents Department
open access

VUV absorption spectroscopy measurements of the role of fast neutral atoms in high-power gap breakdown

Description: The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently-discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. The authors describe a newly-developed diagnostic tool that provides the first direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption… more
Date: March 20, 2000
Creator: Filuk, A. B.; Bailey, James E.; Cuneo, Michael E.; Lake, Patrick Wayne; Nash, Thomas J.; Noack, Donald D. et al.
Partner: UNT Libraries Government Documents Department
open access

Current scaling of axially radiated power in dynamic hohlraums and dynamic hohlraum load design for ZR.

Description: We present designs for dynamic hohlraum z-pinch loads on the 28 MA, 140 ns driver ZR. The scaling of axially radiated power with current in dynamic hohlraums is reviewed. With adequate stability on ZR this scaling indicates that 30 TW of axially radiated power should be possible. The performance of the dynamic hohlraum load on the 20 MA, 100 ns driver Z is extensively reviewed. The baseline z-pinch load on Z is a nested tungsten wire array imploding onto on-axis foam. Data from a variety of x-r… more
Date: March 1, 2007
Creator: Mock, Raymond Cecil; Nash, Thomas J. & Sanford, Thomas W. L.
Partner: UNT Libraries Government Documents Department
open access

Adiabatic Quasi-Spherical Compressions Driven by Magnetic Pressure for Inertial Confinement Fusion

Description: The magnetic implosion of a high-Z quasi-spherical shell filled with DT fuel by the 20-MA Z accelerator can heat the fuel to near-ignition temperature. The attainable implosion velocity on Z, 13-cm/{micro}s, is fast enough that thermal losses from the fuel to the shell are small. The high-Z shell traps radiation losses from the fuel, and the fuel reaches a high enough density to reabsorb the trapped radiation. The implosion is then nearly adiabatic. In this case the temperature of the fuel incr… more
Date: November 1, 2000
Creator: NASH,THOMAS J.
Partner: UNT Libraries Government Documents Department
open access

Scaling and optimization of the radiation temperature in dynamic hohlraums

Description: The authors have constructed a quasi-analytic model of the dynamic hohlraum. Solutions only require a numerical root solve, which can be done very quickly. Results of the model are compared to both experiments and full numerical simulations with good agreement. The computational simplicity of the model allows one to find the behavior of the hohlraum temperature as a function the various parameters of the system and thus find optimum parameters as a function of the driving current. The model is … more
Date: April 13, 2000
Creator: SLUTZ,STEPHEN A.; DOUGLAS,MELISSA R.; LASH,JOEL S.; VESEY,ROGER A.; CHANDLER,GORDON A.; NASH,THOMAS J. et al.
Partner: UNT Libraries Government Documents Department
open access

Dynamics of a Z Pinch X Ray Source for Heating ICF Relevant Hohlraums to 120-160eV

Description: A z-pinch radiation source has been developed that generates 60 {+-} 20 KJ of x-rays with a peak power of 13 {+-} 4 TW through a 4-mm diameter axial aperture on the Z facility. The source has heated NIF (National Ignition Facility)-scale (6-mm diameter by 7-mm high) hohlraums to 122 {+-} 6 eV and reduced-scale (4-mm diameter by 4-mm high) hohlraums to 155 {+-} 8 eV -- providing environments suitable for indirect-drive ICF (Inertial Confinement Fusion) studies. Eulerian-RMHC (radiation-hydrodyna… more
Date: July 10, 2000
Creator: Sanford, Thom W. L.; Olson, Richard E.; Mock, Raymond Cecil; Chandler, Gordon A.; Leeper, Ramon J.; Nash, Thomas J. et al.
Partner: UNT Libraries Government Documents Department
open access

Microfabricated wire arrays for Z-pinch.

Description: Microfabrication methods have been applied to the fabrication of wire arrays suitable for use in Z. Self-curling GaAs/AlGaAs supports were fabricated as an initial route to make small wire arrays (4mm diameter). A strain relief structure that could be integrated with the wire was designed to allow displacements of the anode/cathode connections in Z. Electroplated gold wire arrays with integrated anode/cathode bus connections were found to be sufficiently robust to allow direct handling. Platinu… more
Date: October 1, 2008
Creator: Spahn, Olga Blum; Rowen, Adam M.; Cich, Michael Joseph; Peake, Gregory Merwin; Arrington, Christian L.; Nash, Thomas J. et al.
Partner: UNT Libraries Government Documents Department
open access

Quasi-spherical direct drive fusion.

Description: The authors present designs of quasi-spherical direction drive z-pinch loads for machines such as ZR at 28 MA load current with a 150 ns implosion time (QSDDI). A double shell system for ZR has produced a 2D simulated yield of 12 MJ, but the drive for this system on ZR has essentially no margin. A double shell system for a 56 MA driver at 150 ns implosion has produced a simulated yield of 130 MJ with considerable margin in attaining the necessary temperature and density-radius product for ignit… more
Date: January 1, 2007
Creator: VanDevender, J. Pace; Abbott, Lucas M.; Langston, William L.; McDaniel, Dillon Heirman; Nash, Thomas J.; Roderick, Norman Frederick et al.
Partner: UNT Libraries Government Documents Department
open access

Quasi-spherical direct drive fusion simulations for the Z machine and future accelerators.

Description: We explored the potential of Quasi-Spherical Direct Drive (QSDD) to reduce the cost and risk of a future fusion driver for Inertial Confinement Fusion (ICF) and to produce megajoule thermonuclear yield on the renovated Z Machine with a pulse shortening Magnetically Insulated Current Amplifier (MICA). Analytic relationships for constant implosion velocity and constant pusher stability have been derived and show that the required current scales as the implosion time. Therefore, a MICA is necessar… more
Date: November 1, 2007
Creator: VanDevender, J. Pace; McDaniel, Dillon Heirman; Roderick, Norman Frederick & Nash, Thomas J.
Partner: UNT Libraries Government Documents Department
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