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Facilities
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The principal Center experimental facilities presently include a 450 kA, 100 ns
pulsed power generator (the XP pulser) at Cornell and a 1.4 megampere (MA), 250 ns
device called MAGPIE at Imperial College. In addition, the COBRA generator is being
rebuilt as a 1 MA device (COBRA upgrade) and will be available for experiments starting
in the Fall of 2003. Diagnostic instruments available to Center researchers include
visible light and x-ray streak cameras, visible/UV light and x-ray spectrographs, x-ray
imaging using the X-pinch x-ray source, laser-based imaging methods, including interferometry
and shadowgraphy, etc.
On the left is the configuration known as an X pinch, in which the crossing point of the
two wires forms an unstable z-pinch that collapses to the axis forming a tiny (~ 1 micron),
hot (~1 keV), near solid density plasma. (In the case shown, the wires were molybdenum and
the average ionization state of the radiating plasma was about 30.) In addition to studying
this unique plasma for its own sake, we also make use of it for point-projection imaging such
object plasmas as other X pinches and single exploding wires. An example of the latter is
shown below to the right. The exploding tungsten wire clearly shows a mixed (liquid-vapor)
phase as a result of plasma formation around the wires before the wires are fully vaporized
by a 1 kA current pulse.
While a majority of the research to be carried out by the Center will be experimental, it is
not possible to achieve an understanding of the complex plasma phenomena observed in high
energy density plasmas without the aid of state-of-the-art computer simulation codes. Therefore,
some research activities will involve the development of numerical simulation models to aid in
the understanding of our experimental data, whether they are from wire-array z-pinch implosions,
single-wire explosion tests, astrophysical simulation experiments, or are spectra from highly
stripped, high-Z atoms in near-solid-density plasmas. Still other tasks will be for the purpose
of developing a database for benchmarking computer simulation codes used at the National
Laboratories, such as SNLA’s ALEGRA, and to check equation-of-state and resistivity models
used in those codes.
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