Studies of solid liner stability in electromagnetic implosions

Summary form only given. We have conducted a series of experiments involving electromagnetic implosion of solid aluminium liners on the PEGASUS II capacitor bank. These experiments consisted of liners on which single wavelength perturbations had been cut into the outer surface. Two-dimensional MHD simulations of these experiments with the high conductivity Al-1100 alloy have yielded consistently good agreement, both qualitatively and quantitatively. Because the magnetic diffusion time in this alloy is comparable to or longer than. The growth time, we find that the dynamics can be approximated by theories of Rayleigh-Taylor instability for which strength has been included. Recently, we have conducted two experiments with other aluminum alloys. These alloys have a significantly higher tensile yield strength than the 1100 alloy, but also somewhat high resistivity. Because the magnetic diffusion, ohmic heating, and loss of strength all occur on shorter times than does the growth, the forces acting on the liner are more distributed throughout the liner thickness than on the previous experiments. Qualitatively different features have been observed in the radiographs of these experiments. Two-dimensional MHD simulations and analysis will be presented of both sets of experiments and interpretations of the effect of conductivity on liner stability will be given.