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(IF-4Ra) Progress in Physics of Wire Array Z-pinch Implosions

M.G. Haines1), S.V. Lebedev1), J.P. Chittenden1), S.N. Bland1), F.N. Beg1), M. Sherlock1), A.E. Dangor1)
1) Imperial College, London, United Kingdom

Abstract.  Recent experiments show that the implosion dynamics of wire array Z-pinches is significantly different from that of a thin plasma shell. During the first $ \sim$80% of the implosion the interior of the array is gradually filled by the plasma ablated from the stationary wire cores. This phase ends with the formation of gaps in the wire cores, which occurs due to non-uniformity of the ablation along the wires. The final implosion phase occurs as a snowplough implosion of the radially distributed plasma, previously injected into the interior of the array. The axially peaked density distribution of the precursor plasma leads to a more stable implosion than previously thought, when the Rayleigh-Taylor was assumed to dominate. A hybrid ion Fokker-Planck code with radiation losses was used to describe the dynamics of the plasma flow. The magnetic Reynolds number of the coronal plasma around each wire can be shown in 3-D model to be less than one, thus explaining the current-less inward precursor plasma flow. 2-D and 3-D simulations of wire arrays model the switching of current from the wire plasma to the snowplough implosion.

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IAEA 2003