Plasma formation and implosion structure in wire array Z pinches

The transformation of a cylindrical array of metallic wires into an imploding Z-pinch plasma is described using a 2D resistive magnetohydrodynamics code. The persistence of unionized wire cores dominates the collapse structure. Low-density coronal plasma is swept around the wire cores generating radial plasma streams which reach the axis forming a precursor plasma at roughly half the implosion time. The final stagnation comprises high-density plasma streams impacting onto this precursor. Azimuthal modulation of the plasma is retained throughout. The code accurately reproduces a number of features of experiments with 1 MA currents and predicts qualitatively similar results for higher currents.