Search

A flux compression configuration was designed and tested on the Z accelerator to investigate the possibility of power amplification as well as energy density increase with such a scheme. The front end of Z was redesigned to decouple D level from A, B and C levels. An external coil, generating a quasi-static magnetic field B, in the range of 1 to 5 T, was added. The flux compressing liners were made from 6-cm long 4-cm initial radius W or Al wire arrays. The "armature" liner was imploded under the action of the current from levels A, B, and C into a compression chamber seeded with an azimuthal magnetic field generated with D level. B/sub 2/ was initially applied to the system in order to reduce the growth rate of RT instability. Short circuit loads as well as radiative loads were tested with this stage. These experiments included electrical diagnostics as well as a magnetic pressure measurement with VISAR on shot 356 and radiation diagnostics on shots Z366 and Z428.

Very high current generators are being developed to drive compact loads leading to conductors carrying very high current densities. Losses in conductors include resistive, magnetic field diffusion, pdV work, and material motion contributions. We have designed and executed experiments on Sandia's 100-ns rise time, 20 MA Z accelerator to quantify those losses at current densities reaching 10 MA/cm. In these experiments we delivered nearly 20 MA to both high-current density and low-current density short circuit loads. We used B-dot probes and VISAR techniques to measure the magnetic field near the load. A reduction in the delivered current of /spl sim/15% over the 20 MA peak current prediction made without resistive losses was observed. Comparisons of these data with radiation magneto-hydrodynamics codes (RMHD) are presented. Implications on the efficiency of next generation pulsed power drivers are discussed.