Simulations and analysis of high energy plasma physics of solid liner implosion experiments at Shiva Star.

摘要

The Shiva Star capacitor bank is a large facility located at the Phillips Lab in Kirtland Air Force Base, New Mexico. With a capacity of 1336 microfarads, it is typically charged up to 86 kilovolts to yield a 5 megajoule discharge with a 12 megampere peak current. This current induces a megagauss-level azimuthal magnetic field whose magnetic pressure can be used to implode a conducting aluminum liner in the shape of a spherical shell.; Multiple analyses of such solid liner implosion experiments are modeled using CALE, a two-dimensional finite difference magnetohydrodynamics Lawrence Livermore National Lab code. Typically, such implosions are performed with the spherical shell containing a hydrogen plasma, as well as a target at the center of the sphere. CALE simulations show that such liner implosions can compress a solid metal target to 65-90% above its normal average density. Most of the compression occurs as a result of the metal-on-metal impact of the liner upon the target as opposed to hydrogen plasma pressure.; CALE simulations are compared with x-ray radiographs of actual Shiva Star implosion experiments. Rayleigh-Taylor instabilities of small amplitude and high frequency are visible in these radiographs. CALE simulations show good agreement in modeling the deformation of the liner. However, thin copper targets are seen to deform earlier in simulation than in experiment.