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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 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. 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. A variety of wire array experiments in the last few years at the 20 MA Z accelerator have been performed to assess the impact of initial load mass, initial load diameter, and variations of the nested array configuration on the K-shell output. Nominally, optimized configurations have been identified, with optimization determined by the highest K-shell output with the fastest...
Summary form only given. Precursor plasmas, both the early time precursor flow of mass and the accumulation of this material on axis, have been observed on many z-pinch experiments at various facilities, including low current (< 1 MA, MAGPIE (Bott et al., 2006), Zebra, Cobra) and high current (> 15 MA, Z) facilities. The impact of these precursors on stagnated plasmas, and targets such as those...
Summary form only given. Experiments in the last few years at the 20 MA Z Accelerator have produced significant K-shell X-ray output from a variety of initial load materials, including argon (3 keV, >300 kJ), titanium (4.8 keV, 100 kJ), stainless steel (7 keV, >50 kJ), and copper (8.4 keV, 20 kJ). K-shell scaling theories, developed at NRL, were benchmarked against the K-shell emission data...
Summary form only given. A monochromatic X-ray self-emission imaging diagnostic has been developed for the Z accelerator, which drives 20 MA in 100 ns to implode wire array Z-pinches, generating 200 TW of soft X-ray radiation. This instrument reflects eight pinhole images from a flat Cr/C multilayer mirror (MLM) onto a 1 ns time-resolved microchannel plate detector. The MLM reflects 277 eV photons...
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