Abstract Details
Wire Array Z-Pinch Driven HEDP Experiments on MAGPIE
Author: Simon N Bland
Requested Type: Oral Only
Submitted: 2009-04-20 15:37:10
Co-authors: S. V. Lebedev, J.P. Chittenden, G. N. Hall, A. Harvey-Thompson, F. A. Suzuki-Vidal, G. Swadling, D. J. Ampleford, C. Jennings, A.Critchley, E. Price, and J.B.A. Palmer
Contact Info:
Imperial College London
Blackett Laboratory, Prince Co
South Kensington, London 0000000
UK
Abstract Text:
Wire array z-pinches can be used to drive HEDP experiments in a variety of ways. Most often the X-ray pulse from a cylindrical wire array z-pinch is used to directly or indirectly (via. a hohlraum) heat a target. Access to a cylindrical wire array experiment, however, is often limited to small holes cut in the side of a current return structure. Further, the relatively large scale X-ray source produced at the implosion of a cylindrical array couples to large scale hohlraums (cm-2), limiting the temperatures available for research. We describe experiments with radial wire array z-pinches on the 1MA MAGPIE facility, which are shown to produce a more compact, more efficiently radiating X-ray source than cylindrical arrays. During implosion, this source is also projected above the electrodes providing up to 2π steradians of access. The results of the first scaling experiments to larger currents – the 7MA Saturn generator at Sandia Nationals Laboratories – will be discussed.
Another method of driving HEDP experiments using a wire array z-pinch is to utilize the plasma and/or magnetic fields produced by the array prior to any implosion occurring. The same plasma jets produced by conical wire arrays for our laboratory astrophysics research have been used to exert high pressures on target materials for EOS measurements. Like magnetically driven methods, the ‘jet drive’ provides a steadily increasing pressure that can produce quasi-isentropic compression; this method, however, also decouples the target from the driver allowing the initial conditions of the target to be readily altered. Replacing the wires of an array by a foil, meanwhile, has allowed several new experiments to take place. In particular the foil can be used to enclose a dense, high-Z gas. Initiation of the foil then results in the production of large scale (multi-cm), high speed (60kms-1) radiative shock waves being launched through the gas. The origin of the shocks will be discussed, as will the interaction of shocks with various test objects.
This research was sponsored by the EPSRC, Sandia National Labs through LDRD project 117862 under DoE contract DE-AC04-94AL85000, and the NNSA under DOE Cooperative Agreement DE-FC03-02NA00057.
Comments: