Spherical Wire-Array Implosion Experiments

The results of the first spherical wire array z-pinch implosion experiments are presented. Arrays were driven by the MAGPIE generator (1MA, 240ns) and consisted of 8x25$\mu $m aluminium wires forming the lines of longitude of a sphere with an equatorial diameter of 21mm. Plasma dynamics around each pole of the spherical array are comparable to those observed in radial wire array z-pinch experiments. The smaller radius at the poles produces a higher magnetic field than at the equator, leading to a higher rate of ablation of the wires into plasma. The ablated plasma from each pole forms a jet; and the jets from the poles collide near the centre of the sphere to produce a high-density precursor plasma. Later in time the array implodes, with a pair of plasma bubbles being launched from the poles towards the centre of the array, driving a pair of shock waves onto the precursor plasma. This research was sponsored by Sandia National Laboratories Albuquerque, the SSAA program of NNSA under DOE Cooperative Agreement DE-FC03-02NA00057.