ISSN:
1089-7674
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A beryllium capsule formed from two hemispherical shells with a thin bond is one possible ignition target for the National Ignition Facility [J. A. Paisner et al., Laser Focus World 30, 75 (1994)] Nonuniformities in density, opacity, and interface position at the joint between these hemishells will initiate two-dimensional (2-D) perturbations of the shock wave and material behind the shock as the shock passes through the shell perpendicular to the joint width. Rarefaction of material flow behind the shock front can cause the interface between the shell and joint material to oscillate in position. The amplitude of these oscillations may be comparable to the joint width. The evolution of these perturbations is studied by numerically simulating shock passage through flat beryllium plates containing aluminum joints. Using the MIMOSA-ND code [D. Sofronov et al., Vopr. At. Nauki Tekh., Ser: Mat. modelirovanie fizicheskih processov 2, 3 (1990)] two different cases are calculated—a wide (10 μm) and a narrow (1 μm) joint of aluminum between two 150 μm long semiinfinite beryllium plates. Both cases showed good agreement with an analytic representation of the oscillation behavior. For the narrow joint, a special technique allows the calculation of mixing between the joint and surrounding material caused by the Kelvin–Helmholtz instability. © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.873760
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