Plasma dynamics during the evolution of two wire Z-pinch

Experiments on a two parallel wire Z-pinch are reported. The pinch was driven by a 160 kA peak current, 65 ns 10-90% rise time pulsed power source. Aluminium (15 mum) and tungsten (7.5 mum) wires with varying separations (0.3, 0.6 and 1.5 mm) were used. In addition to the plasma at each wire and its associated corona, a plasma column centred between the wires is formed, well before implosion of the wires. The expansion of the coronal plasma around each wire is asymmetric. Both the wire plasmas and the central plasma develop instabilities--characteristic m = 0 in the wire plasmas and predominantly m = 1 in the central plasma; the m = 0 perturbations in the wires are spatially correlated; the m = 1 perturbations in the central plasma are in the plane containing the wires. The development of instability in the central plasma implies a transfer of some current from the wires to the central plasma.