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ALEGRA-MHD : Version 4.0.

Description: ALEGRA is an arbitrary Lagrangian-Eulerian finite element code that emphasizes large distortion and shock propagation in inviscid fluids and solids. This document describes user options for modeling magnetohydrodynamic, thermal conduction, and radiation emission effects.
Date: November 1, 2003
Creator: Garasi, Christopher Joseph; Haill, Thomas A. & Robinson, Allen Conrad
Partner: UNT Libraries Government Documents Department

Magnetically applied pressure-shear : a new technique for direct strength measurement at high pressure (final report for LDRD project 117856).

Description: A new experimental technique to measure material shear strength at high pressures has been developed for use on magneto-hydrodynamic (MHD) drive pulsed power platforms. By applying an external static magnetic field to the sample region, the MHD drive directly induces a shear stress wave in addition to the usual longitudinal stress wave. Strength is probed by passing this shear wave through a sample material where the transmissible shear stress is limited to the sample strength. The magnitude of the transmitted shear wave is measured via a transverse VISAR system from which the sample strength is determined.
Date: September 1, 2010
Creator: Lamppa, Derek C.; Haill, Thomas A.; Alexander, C. Scott & Asay, James Russell
Partner: UNT Libraries Government Documents Department

Fielding the magnetically applied pressure-shear technique on the Z accelerator (completion report for MRT 4519).

Description: The recently developed Magnetically Applied Pressure-Shear (MAPS) experimental technique to measure material shear strength at high pressures on magneto-hydrodynamic (MHD) drive pulsed power platforms was fielded on August 16, 2013 on shot Z2544 utilizing hardware set A0283A. Several technical and engineering challenges were overcome in the process leading to the attempt to measure the dynamic strength of NNSA Ta at 50 GPa. The MAPS technique relies on the ability to apply an external magnetic field properly aligned and time correlated with the MHD pulse. The load design had to be modified to accommodate the external field coils and additional support was required to manage stresses from the pulsed magnets. Further, this represents the first time transverse velocity interferometry has been applied to diagnose a shot at Z. All subsystems performed well with only minor issues related to the new feed design which can be easily addressed by modifying the current pulse shape. Despite the success of each new component, the experiment failed to measure strength in the samples due to spallation failure, most likely in the diamond anvils. To address this issue, hydrocode simulations are being used to evaluate a modified design using LiF windows to minimize tension in the diamond and prevent spall. Another option to eliminate the diamond material from the experiment is also being investigated.
Date: September 1, 2013
Creator: Alexander, C. Scott; Haill, Thomas A.; Dalton, Devon Gardner; Rovang, Dean Curtis & Lamppa, Derek C.
Partner: UNT Libraries Government Documents Department

ALEGRA-HEDP : version 4.6.

Description: ALEGRA is an arbitrary Lagrangian-Eulerian finite element code that emphasizes large distortion and shock propagation in inviscid fluids and solids. This document describes user options for modeling resistive magnetohydrodynamics, thermal conduction, and radiation transport effects, and two material temperature physics.
Date: February 1, 2005
Creator: Garasi, Christopher Joseph; Cochrane, Kyle Robert; Mehlhorn, Thomas Alan; Haill, Thomas A.; Brunner, Thomas A.; Summers, Randall M. et al.
Partner: UNT Libraries Government Documents Department

ALEGRA-MHD : version 4.6

Description: ALEGRA is an arbitrary Lagrangian-Eulerian finite element code that emphasizes large distortion and shock propagation in inviscid fluids and solids. This document describes user options for modeling resistive magnetohydrodynamic, thermal conduction, and radiation emission effects.
Date: January 1, 2005
Creator: Garasi, Christopher Joseph; Cochrane, Kyle Robert; Mehlhorn, Thomas Alan; Haill, Thomas A.; Summers, Randall M. & Robinson, Allen Conrad
Partner: UNT Libraries Government Documents Department

The Role of Strong Coupling in Z-Pinch-Driven Approaches to High Yield Inertial Confinement Fusion

Description: Peak x-ray powers as high as 280 {+-} 40 TW have been generated from the implosion of tungsten wire arrays on the Z Accelerator at Sandia National Laboratories. The high x-ray powers radiated by these z-pinches provide an attractive new driver option for high yield inertial confinement fusion (ICF). The high x-ray powers appear to be a result of using a large number of wires in the array which decreases the perturbation seed to the magnetic Rayleigh-Taylor (MRT) instability and diminishes other 3-D effects. Simulations to confirm this hypothesis require a 3-D MHD code capability, and associated databases, to follow the evolution of the wires from cold solid through melt, vaporization, ionization, and finally to dense imploded plasma. Strong coupling plays a role in this process, the importance of which depends on the wire material and the current time history of the pulsed power driver. Strong coupling regimes are involved in the plasmas in the convolute and transmission line of the powerflow system. Strong coupling can also play a role in the physics of the z-pinch-driven high yield ICF target. Finally, strong coupling can occur in certain z-pinch-driven application experiments.
Date: November 8, 1999
Creator: MEHLHORN,THOMAS A.; DESJARLAIS,MICHAEL P.; HAILL,THOMAS A.; LASH,JOEL S.; ROSENTHAL,STEPHEN E.; SLUTZ,STEPHEN A. et al.
Partner: UNT Libraries Government Documents Department

ALEGRA : version 4.6.

Description: ALEGRA is an arbitrary Lagrangian-Eulerian multi-material finite element code used for modeling solid dynamics problems involving large distortion and shock propagation. This document describes the basic user input language and instructions for using the software.
Date: January 1, 2005
Creator: Wong, Michael K. W.; Summers, Randall M.; Petney, Sharon Joy Victor; Luchini, Christopher Bernard; Drake, Richard Roy; Carroll, Susan K. et al.
Partner: UNT Libraries Government Documents Department

ALEGRA: User Input and Physics Descriptions Version 4.2

Description: ALEGRA is an arbitrary Lagrangian-Eulerian finite element code that emphasizes large distortion and shock propagation. This document describes the user input language for the code.
Date: October 1, 2002
Creator: BOUCHERON, EDWARD A.; BROWN, KEVIN H.; BUDGE, KENT G.; BURNS, SHAWN P.; CARROLL, DANIEL E.; CARROLL, SUSAN et al.
Partner: UNT Libraries Government Documents Department