ALEGRA: An Arbitrary Lagrangian-Eulerian Multimaterial, Multiphysics Code

Robinson, Allen C.; Strack, Otto D. L.; Drake, Richard Roy; Wong, M. W.; Weirs, V. Gregory; Voth, Thomas Eugene; Hanshaw, Heath L.; Brunner, Thomas A.; Carroll, Susan K.; Mosso, Stewart John; Petney, Sharon; Scovazzi, Guglielmo; Rider, William J.; Ober, Curtis C.; Garasi, Christopher J.; Neiderhaus, John; Love, Edward; Lemke, R.W.; Summers, R.M.

doi:10.2514/6.2008-1235

Cited by 88 publications

(54 citation statements)

References 51 publications

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“…All aspects of the MAPS experiment (driver, sample, and anvil dimensions; current pulse shape) were designed using the ALEGRA hydrocode [16]. A 2D Cartesian geometry with an Eulerian mesh (5-10 micron cells) was used and is illustrated in figure 5.…”

Section: Experimental Designmentioning

confidence: 99%

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

Alexander¹,

Haill²,

Dalton³

et al. 2013

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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. ACKNOWLEDGEMENTS

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Section: Experimental Designmentioning

confidence: 99%

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

Alexander¹,

Haill²,

Dalton³

et al. 2013

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“…In 2104 liner specifications were inner radius Ri=0.239 cm, outer radius Ro=0.319 cm, aspect ratio AR=4, and mass per length m=0.259 g/cm; in 2207 Ri=0.20 cm, Ro=0.29 cm, AR=3.2, and m=0.256 g/cm. Two-dimensional simulations are performed using the multi-dimensional, radiation, magnetohydrodynamics (RMHD) code ALEGRA [22]. In both cases the MRT instability is initiated by a 100 nm perturbation of the outer radius that is random in the z-direction.…”

Section: On the Possibility Of Current Pulse Shaping To Improve Stabimentioning

confidence: 99%

“…ALEGRA simulation verifies that the shock in the z2104 liner attained a peak pressure of about 3.8 Mbar, which heats the material sufficiently to melt it. ALEGRA simulation shows that the liner in z2207 implodes shocklessly, with some fraction of the material remaining in the solid state until stagnation [22]. Figure 18 is a plot of shear strength G vs. time at Lagrangian locations near the liner inner surface.…”

Section: On the Possibility Of Current Pulse Shaping To Improve Stabimentioning

confidence: 99%

Stability of fusion target concepts on Z.

Sinars¹,

McBride²,

Rovang³

et al. 2012

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The key scientific issue for magnetically driven fusion concepts is the stability of the cylindrical liner surrounding the fuel. The liner is susceptible to the magnetoRayleigh-Taylor instability, which can disrupt the liner implosion and prevent it from successfully compressing and confining the fuel. We summarize an LDRD project to investigate the stability of aluminum and beryllium liner implosions on the Sandia Z pulsed power facility. Much of the work was conducted in the specific context of a new magnetized liner inertial fusion (MagLIF) concept, and continued modeling of that concept was supported by this project. However, the liner stability data is fundamental to magnetically driven systems, and the idea of magnetizing and preheating fuel applies to any inertial confinement fusion platform. We also demonstrated prototype 10 T axial magnetic field coils, which are needed both to test the MagLIF concept and the idea of stabilizing liner implosions using magnetic fields. 4 ACKNOWLEDGMENTSWe thank the many Z and Z-Beamlet operations and production teams for their excellent support of the liner stability experiments on Z that were undertaken as part of this project.We thank General Atomics for their support in developing and fabricating the liner targets fielded on the Z facility. Much of the work described here would not have been possible without the development of a beryllium machining capability in La Jolla, CA.We thank Ron Kaye (Manager, Org. 5445) for supporting the development of the Systems Integration and Test Facility in his laboratory space and for the use of Derek Lamppa and Marc Jobe to support the development of magnetic field coils.We thank Jim Puissant (Org. 1647) for supporting the magnetic field coil design and testing activities.We thank TJ Rogers (formerly Org. 1678) for designing the raised power-feed hardware for Z that is compatible with the magnetic field coils, and was tested during the "Washington" shots.We thank Dawn Flicker (Manager, Org. 1646) for supporting the collaboration between the ICF and Dynamic Materials program that enabled the "Union" experiments on Z. These experiments, while explicitly aimed at studying the equation of state of beryllium using cylindrical liners, are also relevant to ICF implosions and the techniques may ultimately benefit MagLIF.We thank the code support teams at LLNL for both LASNEX and HYDRA for helping us to advance the simulations conducted as part of this project. We also thank the support staff at numerous computing platforms at both SNL and LLNL who helped shepherd the simulations through to completion.

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“…ALEGRA is a series of multi-physics codes designed and developed by the Computational Shock and Multiphysics, and HEDP Theory Departments at Sandia National Laboratories [7]. The simulations were completed on AWE supercomputers utilizing 80 CPUs per simulation run.…”

Section: Alegra Magnetohydrodynamicsmentioning

confidence: 99%

High fidelity studies of exploding foil initiator bridges, Part 3: ALEGRA MHD simulations

Neal

Garasi

2017

AIP Conference Proceedings

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Abstract. Simulations of high voltage detonators, such as Exploding Bridgewire (EBW) and Exploding Foil Initiators (EFI), have historically been simple, often empirical, one-dimensional models capable of predicting parameters such as current, voltage, and in the case of EFIs, flyer velocity. Experimental methods have correspondingly generally been limited to the same parameters. With the advent of complex, first principles magnetohydrodynamic codes such as ALEGRA and ALE-MHD, it is now possible to simulate these components in three dimensions, and predict a much greater range of parameters than before. A significant improvement in experimental capability was therefore required to ensure these simulations could be adequately verified. In this third paper of a three part study, the experimental results presented in part 2 are compared against 3-dimensional MHD simulations. This improved experimental capability, along with advanced simulations, offer an opportunity to gain a greater understanding of the processes behind the functioning of EBW and EFI detonators.

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ALEGRA: An Arbitrary Lagrangian-Eulerian Multimaterial, Multiphysics Code

Cited by 88 publications

References 51 publications

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

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

Stability of fusion target concepts on Z.

High fidelity studies of exploding foil initiator bridges, Part 3: ALEGRA MHD simulations

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