Implosion and stagnation of wire array Z pinches

Journal Article · Tue May 15 04:00:00 EDT 2007 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2671940· OSTI ID:20975071

Bland, S N; Lebedev, S V; Chittenden, J P; Hall, G N; Suzuki-Vidal, F; Ampleford, D J; Bott, S C; Palmer, J B. A.; Pikuz, S A; Shelkovenko, T A ^[1]

---

1. Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

Detailed measurements of the dynamics of aluminum wire array Z pinches from immediately prior to implosion until stagnation and dissipation on axis are presented. Before implosion, the {approx}0.5 mm axial modulation seen in earlier laser probing images is observed as ablation on the surface of the wire cores facing away from the array axis. This results in the complete ablation of sections of the wire cores and a redistribution of current at the start of implosion. The dynamics of implosion are then strongly influenced by the number of wires in the array. With only eight wires, discrete snowplough bubbles expand from each wire toward the precursor. There is little, if any, correlation between the bubbles from adjacent wires, and a large temporal spread over which the bubbles arrive at the precursor is observed, along with a long rise time, low power soft x-ray pulse. With 32 or more wires, bubbles from adjacent wires merge close to the array edge to form an imploding sheath. The front edge of the sheath is well defined with a small spatial spread, and upon reaching the precursor, the start of a fast rising high power soft-x-ray pulse is seen. As x-ray emission increases, the stagnating column on axis starts to decrease in diameter, reaching a minimum at peak x-ray emission, which also coincides with the time when the rear edge of the snowplough reaches the column. Thereafter, the stagnated column is seen to go unstable, and trailing mass left behind during the implosion is accelerated toward the axis. Intense x-ray emission ends as this mass becomes cleared out.

• OSTI ID: 20975071
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 14; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ABLATION
ALUMINIUM
BOUNDARY LAYERS
BUBBLES
CURRENTS
EXPLODING WIRES
IMPLOSIONS
LASERS
PINCH DEVICES
PLASMA
PLASMA DIAGNOSTICS
PLASMA SHEATH
PULSE RISE TIME
PULSES
SOFT X RADIATION
STAGNATION
X-RAY SOURCES