Title :
Conical Wire Array Z-Pinches as a Tool to Explore the Physics of Wire Array Z-Pinches and for Radiation Pulse-Shaping
Author :
Ampleford, D.J. ; Lebedev, S.V. ; Ciardi, A. ; Bland, S.N. ; Bott, S.C. ; Chittenden, J.P. ; Hall, G.N. ; Jennings, C.A. ; Rapley, J.
Author_Institution :
Blackett Lab., Imperial Coll., London
Abstract :
Summary form only given. We investigate the use of the conical wire array Z-pinch to test the understanding of wire array Z-pinches using the MAGPIE generator (1 MA, 240 ns). In contrast to previous experiments that have used the precursor plasma flows in a conical wire array to model proto-stellar jets, here we concentrate on the dynamics of the conical wire array. The variation in magnetic field and inter-wire gap along the wire make conical arrays apt for testing the understanding of wire ablation. Mass ablation at different axial positions agrees with a rocket model with a fixed ablation velocity, and hence the mass ablation rate is inversely proportional to radius. Modulations in wire ablation are observed similar to those in cylindrical wire arrays. The wavelength of these modulations is similar to those in cylindrical arrays, and is fixed along the length of the wire. Near the wire the ablated plasma streams display an un-expected curved trajectory towards the anode. The axial variation of global magnetic field also affects the implosion phase of conical wire arrays, with wire breakage occurring first at the smaller diameter, cathode end of the array. The X-ray pulse shape is different from cylindrical wire arrays, partially due to an axial variation in the implosion time. In experiments with a large wire inclination angle a current carrying bubble is formed at the base of the array which propagates upwards
Keywords :
Z pinch; exploding wires; explosions; plasma X-ray sources; plasma flow; 1 MA; 240 ns; MAGPIE generator; X-ray pulse shape; conical wire array Z-pinches; current carrying bubble; cylindrical wire arrays; global magnetic field; implosion; mass ablation; plasma flows; protostellar jets; radiation pulse-shaping; rocket model; Anodes; Magnetic fields; Phased arrays; Physics; Plasma displays; Plasma waves; Plasma x-ray sources; Rockets; Testing; Wire;
Conference_Titel :
Plasma Science, 2005. ICOPS '05. IEEE Conference Record - Abstracts. IEEE International Conference on
Conference_Location :
Monterey, CA
Print_ISBN :
0-7803-9300-7
DOI :
10.1109/PLASMA.2005.359360