Implosions of wire arrays with mixed materials and wire diameters

Summary form only given. The results of experiments on the MAGPIE generator (1.4 MA, 240 ns) with single wire arrays composed from wires of two different materials (e.g. W and Al) or from wires of different diameters will be presented. The wires are placed in an array alternately on the same diameter, and this configuration of the array is used to investigate effects of material or wire diameter on the division of current between the wires. It was found that in a 32 Al/W mixed wire array, the Al wires implode significantly earlier than W wires, despite the fact that mass per unit length was the same for both materials. This presumably occurs due to a higher conductivity of plasma formed from Al wires, in which most of the total current flows during the first /spl sim/70% of the implosion time. The difference in the implosion times of the two parts of the mixed wire arrays allows us to separate experimentally the contributions to the X-ray pulse from the kinetic energy and from the compression of the plasma by the magnetic field. This also suggests a possibility to control the shape of the X-ray pulse, in a way similar to the nested wire arrays operating in a current switching mode.