Theory and simulation of liner implosions at thirty megaamperes

Summary form only given. The next generation of high current, pulsed-power machine to be built is Atlas. Atlas is a 24 MJ, pulsed power facility being constructed at Los Alamos National Laboratory in support of the Department of Energy´s stockpile stewardship program. It is projected to be operational in the year 2000, and capable of providing 100 shots per year. In support of stockpile stewardship Atlas will be used to investigate states of matter under extreme conditions. Included in these investigations will be equation-of-state (EOS) experiments performed at pressures exceeding 10 megabars. Hugoniot measurements at these pressures, and in convergent geometry represent an exciting challenge for the experimentalist. Results from one-dimensional simulations indicate that pressures exceeding ten megabars can be generated when an aluminum/tungsten liner collides with a hollow tungsten target placed at a radius of approximately 1 cm. However, in order to accurately infer a hugoniot from the measurements will require that the impactor be relatively flat and solid over a sufficiently large surface area. Thus, success will rely upon our ability to stably implode thin, composite-material liners to velocities greater than 10 km/ms, with a portion of the liner remaining in the solid phase. At peak currents of 27.5 MA much of the liner is melted at early times within the implosion, making it susceptible to growth of Rayleigh-Taylor instabilities. In addition to these instabilities feeding through to the inner or outer tungsten surfaces, bowing of this surface may arise due to interaction with the angled glide plane. In this poster we present results of two-dimensional MHD simulations that incorporate these effects on liner integrity. Theoretical predictions for growth rates in the presence of strength in the materials will also be presented.