Plasma jet for pre-conditioning of a carbon fibre Z-pinch

Summary form only given, as follows. Previous experiments on the Imperial College MAGPIE generator have shown that plasma produced from the pre-ionisation of 33 /spl mu/m carbon fibres, by current pre-pulse, helps reduce expansion velocity during initial stages of explosion. However the current-ablative method used gives very little control over the pre-ionisation plasmas characteristics. A capillary discharge device has been developed to inject a plasma jet around a fibre to use instead of the fibre pre-ionisation by current pre-pulse. This allows us to produce plasma with larger line densities and diameters in a more controllable way. Interferometer measurements on the jet have shown it can develop plasma around the fibre with a line density about 10/sup 18/ cm/sup -1/ and diameters varying from /spl sim/2 mm at the point of injection (anode) to /spl sim/1 cm at the cathode of the Z-pinch. It is planned to use an axial magnetic field of /spl sim/2 KG to try to improve the homogeneity of the jet along the fibre. Comparison of the results of carbon fibre z-pinch experiments taken with and without the plasma jet will be presented.