A review of the dense Z-pinch

Plasma Phys. Control. Fusion 53 (2011) 093001
Topical Review
Figure 38. Aluminium K-shell x-ray power versus time on the Saturn generator for 10, 16, 24,
48 and 90 wires. Reprinted figure 4 with permission from [20]. Copyright 1996 by the American
Physical Society.
Figure 39. Current and x-ray power for a nested tungsten wire array on the Z-accelerator at Sandia
showing four distinct phases; wire initiation, ablation, acceleration, and stagnation. Reprinted with
permission from [323]. Copyright 2005 by the American Physical Society.
Although it has been known for some years that, at least when using a small number of
wires, there is a precursor plasma [316–320], flowing from the wires towards the axis, this was
ignored in the early interpretation and modelling of the data [321]. However, when following
the implosion trajectory of the plasma [65] it markedly deviates from the 0D trajectory of a
shell (section 4.4) as shown in figure 40. Indeed the wire cores remain stationary from 50% up
till 80% of the implosion time, the inward global J × B force causing only the ablated coronal
plasma which carries most of the current to be accelerated as a precursor, leaving the current
behind. The precursor accumulates on the axis as a cylindrical column. However, when gaps
appear in the wire cores (associated with necks in the m = 0 instability on each wire), the main
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