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Milestone 7720: National Opacity Program - Tri-Lab Assessment of Measurements and Models

Hansen, Stephanie B.; Heeter, Robert; Johns, Heather; Nagayama, Taisuke; Loisel, Guillaume P.; Bailey, James E.

Opacity-on-NIF has obtained opacity data under conditions similar to those achieved by the entirely different Opacity-on-Z platform. From low- and high-Z elements at different anchor points, rigorously compare the opacity data between the laboratories and to multiple opacity theory models. Compare and assess the data acquisition and processing methods for obtaining opacities and for measuring/inferring sample conditions. Explain, or develop hypotheses for, any discrepancies. Map progress to the National Opacity Strategy and define future directions.

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TYPE Other Report YEAR 2023
DOIOSTI

Radiatively-Cooled Magnetic Reconnection Experiments at the Z Pulsed-Power Facility

Hare, Jack; Datta, Rishabh; Sergey, Lebedev; Chittenden, Jerry; Crilly, Aidan; Bland, Simon; Halliday, Jack; Russell, Danny; Fox, Will; Hantao, Ji; Kuranz, Carolyn; Myers, Clayton; Aragon, Carlos; Jennings, Christopher A.; Ampleford, David J.; Beckwith, Kristian; Harding, Eric H.; Hansen, Stephanie B.; Dunham, G.S.; Edens, Aaron; Gonzalez, Josue; Harmon, Roger; Kellogg, Jeffrey; Jones, Michael; Looker, Quinn M.; Molina, Leo; Montoya, Michael; Patel, Sonal G.; Loisel, Guillaume P.; Speas, Christopher S.; Webb, Timothy J.; Yager-Elorriaga, David A.; Shipley, Gabriel A.; Chandler, Katherine M.

Abstract not provided.

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TYPE Conference Presenation YEAR 2022
DOIOSTI

Domination of the K-Radiation at a Z-Pinch Stagnation on Z by Numerous Tiny Spots and the Properties of the Spots Inferred by Experimental Determination of the K-Line Opacities

IEEE International Conference on Plasma Science

Maron, Y.; Bernshtam, V.; Zarnitsky, Y.; Fisher, V.; Nedostup, O.; Ampleford, David J.; Jennings, Christopher A.; Jones, Brent M.; Cuneo, Michael E.; Rochau, G.A.; Dunham, G.S.; Loisel, Guillaume P.

Detailed analysis of both the line-intensity ratios and line shapes of the K-lines of elements of different abundances (Fe, Cr, Ni, and Mn) emitted from the stagnation of a steel wire-array implosion on Z, were used to determine the line opacities. While the opacities at the early time of stagnation appear to be consistent with a nearly uniform hot-plasma cylinder on-axis surrounded by a colder annulus, the opacities during the peak K-emission strongly suggest that the main K-emission is due to small hot regions (spots) spread over the stagnating column. The spots are shown to be at least 4× denser than expected based on a uniform-cylinder emission (namely, ni > 3 ×1020 cm-3 ), are of diameters of about 200 μ or less (where the smaller the spots the higher are the densities), and are thousands in number. The total mass of the spots was determined to be 3-10 % of the load mass, and their total volume 3-15 % of the O 1.2-mm stagnation-column volume, both are less than the respective values for the earlier period of lower K power.

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TYPE Conference Presenation YEAR 2022
DOIOSTIScopus

Background measurement methods for opacity experiments conducted at the Z facility

Review of Scientific Instruments

Dunham, G.S.; Nagayama, Taisuke; Bailey, James E.; Loisel, Guillaume P.

Laboratory experiments typically test opacity models by measuring spectrally resolved transmission of a sample using bright backlight radiation. A potential problem is that any unaccounted background signal contaminating the spectrum will artificially reduce the inferred opacity. Methods developed to measure background signals in opacity experiments at the Sandia Z facility are discussed. Preliminary measurements indicate that backgrounds are 9%-11% of the backlight signal at wavelengths less than 10 Å. Background is thus a relatively modest correction for all Z opacity data published to date. Future work will determine how important background is at longer wavelengths.

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TYPE Journal Article YEAR 2021
DOIOSTIScopus
Results 1–25 of 122
Results 1–25 of 122