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A number of shots employing concentric gas puffs of Ar and Kr on the Sandia National Laboratories ZR accelerator are being planned; with the goal of optimizing K-shell yield. Experimental data from these implosions can provide a wealth of information about the pinch dynamics and ionization history of the plasma. Theoretical simulations using accurate atomic and hydrodynamics models will provide synthetic...
Emission line ratios have been used as an effective diagnostic for the determination of the plasma parameters. However, the treatment of doubly excited states in such models can affect the ionization dynamics which can subsequently alter the emission line ratios and absolute powers used for plasma diagnostics. Prior models have also assumed that the electron energy distribution function (EEDF) is...
Advances in diagnostics at the refurbished Z facility at Sandia National Laboratories (SNL) now allow spatially and temporally resolved spectra to be obtained, with improved signal-to-noise ratios. Z-pinch simulation models have also improved, due both to substantial advances in the understanding of the underlying physics, and to the development of more detailed and accurate atomic databases. We will...
Large diameter (50-70 mm) wire array z pinches are fielded on the refurbished Z machine to generate 1-10 keV K-shell x-ray radiation. Imploding with velocities approaching 100 cm/μs, these loads create large dL/dt which generates a high voltage, stresses the convolute, and leads to current loss. High velocities are required to reach the few-keV electron temperatures required to strip moderate-atomic-number...
We will discuss experiments on the Z generator using large diameter stainless steel wire arrays to produce K-shell emission (hv~6.7keV). Large array diameters and fast implosion times are needed to obtain high velocities and high temperatures in order to excite Fe K-shell emission.Since the refurbishment of the Z generator, nested stainless steel wire arrays have been fielded at 65mm, 70mm and 75...
A series of Al/Mg nested wire array Z-pinch load experiments has been recently performed on the refurbished Z accelerator. The earlier comparison study of the results from ID and 2D radiation MHD simulations of the Sandia Z1907/1908 experiments [Y. K. Chong, et. al, APS09] has shown that, in addition to the substantial difference in the prediction capability of the ID and 2D models, the radiation...
A two-dimensional radiation MHD model that includes a self-consistent calculation for non-local thermodynamic equilibrium kinetics and ray trace based radiation transport1 is employed to simulate 65 mm diameter stainless steel double wire array Z machine experiments of 5.0 mg and 2.5 mg, respectively (shots Z1859 and Z1860). Temporal knowledge of the plasma internal energy, ion density, velocity,...
Summary form only given. Fast z-pinches produce intense K-shell radiation from wire arrays and for Cu arrays these photon energies can exceed 8 keV Experimental investigations of pinches on ZR using Cu arrays have already begun and more are planned for the near future. However to produce significant K-Shell emissions from moderately high atomic number plasmas such as Cu, they must be rapidly ionized...
Summary form only given. Copper wire arrays have previously been fielded in large diameter (up to 70 mm) nested configurations on the 20 MA Z machine, with average Cu K-shell (8.4 keV) yields of 20 kJ typical. More recently, Cu K-shell source development studies have been performed on the refurbished Z machine, which in initial commissioning shots has produced just over 20 MA current in these loads...
Summary form only given. A two-dimensional radiation MHD model was recently developed and employed to investigate large diameter wire array Z-pinch experiments performed on the refurbished Z generator. This model incorporates into the Mach2 MHD code a self-consistent calculation for non-local thermodynamic equilibrium kinetics and ray trace based radiation transport. This level of detail is necessary...
We have developed a collisional-radiative spectroscopic model that combines the completeness of highly averaged Rydberg states models with the accuracy of detailed models for all important excited states. Our model includes an abundance of levels and atomic structure data as well as collisional and radiative processes including excitation, ionization, and recombination level couplings. This approach...
We present results from initial large diameter wire array experiments at the refurbished Z generator. 65mm on 32.5mm nested stainless steel wire arrays were fielded at two different total masses (2.5mg & 5mg). Each array was 20mm tall and had an inner array half the mass of the outer. The experiments were designed to evaluate trends in Fe K-shell power and yield and re-establish previous output,...
Summary form only given. K-shell X-rays have been studied with various materials at the 20-MA (pre-refurbished) Z accelerator. This paper presents results obtained for the ablation dynamics and stagnation physics of single and nested copper z-pinches with varying initial load diameters. Monochromatic imaging and shadowgraphy provide detailed information regarding the ablation of the wires and the...
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