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5. X-ray radiation from puff-on-wire implosions on the COBRA generator

Author

Ouart, N.D., primary, Giuliani, J.L., additional, Dasgupta, A., additional, Velikovich, A.L., additional, Engelbrecht, J., additional, de Grouchy, P., additional, Qi, N., additional, Shelkovenko, T., additional, Pikuz, S., additional, Kusse, B., additional, Hammer, D., additional, Apruzese, J.P., additional, and Clark, R.W., additional

Published
2016
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6. Study of Triple Ar Gas Puff Z-Pinches on 0.9-MA, 200-ns COBRA.

Author

Qi, N., Rocco, S. V., Engelbrecht, J., Lavine, E. S., de Grouchy, P., Banasek, J. T., Atoyan, L., Byvank, T., Potter, W. M., Greenly, J. B., Hammer, D. A., Kusse, B. R., Pikuz, S. A., Shelkovenko, T. A., Kroupp, E., Fisher, A., and Maron, Y.

Subjects
*MAGNETIC fields, *PLASMA gases, *PLASMA compression, *PHOTOCONDUCTIVITY, *ELECTRIC potential, *ELECTROMAGNETIC theory
Abstract

Ar gas puff z-pinch experiments were conducted on the 0.9-MA, 200-ns COBRA generator at Cornell University. In the experiments, a triple-nozzle gas valve was used to produce the z-pinch load with concentric outer and inner gas puffs and a central gas jet. We used a planer laser-induced fluorescence to measure the initial gas profile of the load, two four-frame 4-ns gated extreme ultraviolet cameras to image the imploding plasma, and filtered photoconducting diamond detectors to measure the X-ray output. We have observed the shock heating and/or photoionization of the dense center jet by the imploding plasma. With an outer-to-inner plenum pressure ratio of 1:3, deacceleration of the imploding plasma occurred when the outer plasma shell imploded on the inner shell resulting in a stable implosion. By varying the plenum pressure for the center jet, the X-ray emission was optimized. An Ar K-shell X-ray (3–4 keV) yield of 77 ± 17 J was produced at a current level of 0.87 ± 0.2 MA and an implosion time of 200 ns. [ABSTRACT FROM AUTHOR]

Published
2018
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7. Rayleigh-Taylor instability amplification due to radiative losses

Author

de Grouchy, P., primary, Qi, N., additional, Kusse, B. R., additional, Atoyan, L., additional, Banasek, J., additional, Byvank, T., additional, Cahill, A. D., additional, Engelbrecht, J., additional, Moore, H., additional, Ransohoff, L., additional, Tian, S., additional, Hammer, D. A., additional, Pikuz, S. A., additional, and Shelkovenko, T. A., additional

Published
2015
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8. Neon and argon multi-nozzle gas puff z-pinch studies on COBRA

Author

Qi, N., primary, De Grouchy, P., additional, Potter, W., additional, Banasek, J., additional, Engelbrecht, J., additional, Atoyan, L., additional, Cahill, A. D., additional, Greenly, J. B., additional, Hoyt, C. L., additional, Pikuz, S. A., additional, Shelkovenko, T. A., additional, Hammer, D. A., additional, Kusse, B. R., additional, Chong, Y. K., additional, Giuliani, J., additional, Ouart, N., additional, Thornhill, W., additional, Kroupp, E., additional, Fisher, A., additional, and Maron, Y., additional

Published
2015
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9. Triple nozzle gas-puff z-pinch implosions on COBRA

Author

de Grouchy, P., primary, Qi, N., additional, Kusse, B.R., additional, Atoyan, L., additional, Cahill, A.D., additional, Gourdain, P.A., additional, Greenly, J.B., additional, Hoyt, C.L., additional, Potter, W.M., additional, Schrafel, P.C., additional, Hammer, D. A., additional, Pikuz, S.A., additional, and Shelkovenko, T.A., additional

Published
2014
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11. Gas puff Z-pinch implosions on COBRA

Author

Qi, N., primary, Rosenberg, E. W., additional, Gourdain, P. A., additional, Rondeau, G., additional, Hoyt, C., additional, Blesener, K. S., additional, Kusse, B. R., additional, Greenly, J., additional, and Hammer, D. A., additional

Published
2013
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16. Results from recent argon-gas-puff experiments at ∼ 6 MA

Author

Commisso, R.J., primary, Apruzese, J.P., additional, Jackson, S.L., additional, Mosherb, D., additional, Murphy, D.P., additional, Phipps, D.G., additional, Weber, B.V., additional, Coleman, P.L., additional, Wilson, K., additional, Qi, N., additional, Coverdale, C.A., additional, Jones, B., additional, and Mikkelson, K., additional

Published
2008
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17. Energetics of a long-implosion-time, 12-cm-diameter argon-gas-puff Z pinch at 6.5 MA

Author

Commisso, R.J., primary, Apruzese, J.P., additional, Mosher, D., additional, Murphy, D.P., additional, Weber, B.V., additional, Banister, J.W., additional, Failor, B.H., additional, Levine, J.S., additional, Qi, N., additional, Sze, H.M., additional, Bixler, A., additional, Coleman, P.L., additional, Jarema, A., additional, Knight, J., additional, Lee, S., additional, Krishnan, M., additional, Thompson, J., additional, Wilson, K., additional, Coverdale, C.A., additional, and Deeney, C., additional

Published
2007
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18. Long-Implosion-Time, 12-cm-Diameter Argon-Gas-Puff Experiments at 6 MA

Author

Commisso, R.J., primary, Apruzese, J.P., additional, Davis, J., additional, Holt, T.A., additional, Mosher, D., additional, Murphy, D.P., additional, Thornhill, J.W., additional, Velikovich, A.L., additional, Weber, B.V., additional, Young, F.C., additional, Banister, J.W., additional, Failor, B.H., additional, Levine, J.S., additional, Qi, N., additional, Sze, H.M., additional, Bixler, A., additional, Coleman, P.L., additional, Jarema, A., additional, Knight, J., additional, Lee, S., additional, Krishnan, M., additional, Thompson, J., additional, Wilson, K., additional, Coverdale, C.A., additional, and Deeney, C., additional

Published
2007
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20. High Current Wire Array and Gas Puff Implosions on the Z Accelerator to Produce Intense K-Shell X-Ray Emissions

Author

Coverdale, C.A., primary, Deeney, C., additional, Jones, B., additional, LePell, P.D., additional, Velikovich, A.L., additional, Thornhill, J.W., additional, Apruzese, J.P., additional, Whitney, K.G., additional, Clark, R.W., additional, Davis, J., additional, Levine, J.S., additional, Sze, H.M., additional, Banister, J.W., additional, Failor, B.H., additional, Qi, N., additional, and Maron, Y., additional

Published
2006
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24. The Effect of the Initial Density Profile on K-Shell Emission in Two-Dimensional Simulations of Argon Gas-Puff z Pinches

Author

Thornhill, J.W., primary, Chong, Y. K., additional, Apruzese, J. P., additional, Davis, J., additional, Velikovich, A. L., additional, Clark, R. W., additional, Terry, R. E., additional, Commisso, R. J., additional, Frese, M.H., additional, Frese, S. D., additional, Failor, B.H., additional, Levine, J.S., additional, Qi, N., additional, Sze, H., additional, Bixler, A., additional, Coleman, P., additional, Thompson, J., additional, and Krishnan, M., additional

Published
2005
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28. Overview of Recent Large-Diameter, Gas-Puff Z-Pinch Research

Author

Commisso, R.J., primary, Velikovich, A.L., additional, Weber, B.V., additional, Young, F.C, additional, Banister, J.W., additional, Failor, B.H., additional, Levine, J.S., additional, Qi, N., additional, Sze, H., additional, Bixler, A., additional, Coleman, P., additional, Apruzese, J.P., additional, Krishnan, M., additional, Thompson, J., additional, Carlson, E., additional, Hazelton, R.C., additional, Yadlowsky, E.J., additional, Davies, F., additional, De LaCruz, C., additional, Chong, Y.K., additional, Davis, J., additional, Frese, M. H., additional, Mosher, D., additional, Murphy, D.P., additional, Phipps, D.G., additional, and Thornhill, J.W., additional

Published
2005
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29. Investigation of an 8-CM Diameter, Neon Gas Z-Pinch

Author

Murphy, D.P., primary, Commisso, R. J., additional, Weber, B.V., additional, Mosher, D., additional, Phipps, D. G., additional, Stephanakis, S. J., additional, Young, F. C., additional, Ponce, D. M., additional, and Qi, N., additional

Published
2005
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32. Neon Z-pinch experiments on hawk to optimize K-shell radiation from 300 ns implosions.

Author

Murphy, D. P., Hinshelwood, D. D., Commisso, R. J., Mosher, D., Phipps, D. G., Ponce, D. M., Stephanakis, S. J., Weber, B. V., Young, F. C., and Qi, N.

Abstract

One of the objectives of the Plasma Radiation Source research program on the Decade Quad machine (6 MA, 300 ns implosion time) program is to optimize the K-shell yield for large-radius, long-implosion-time argon gas-puff Z-pinches. The NRL HAWK generator (0.6 MA, 300 ns implosion time) driving a neon gas puff is a convenient test bed to study yield dependence on density profile, implosion time, return current symmetry, etc‥ Neon on Hawk is energetically equivalent to argon on Decade Quad [1]. The HA WK neon experiments employ the Titan 1234 double-shell gas-puff valve and nozzle [2] used in higher-Current argon experiments [3]. Here, we report on experiments to determine dependence of K-shell yield on gas-puff density profile by varying the inner and outer plenum pressures over a wide range. [ABSTRACT FROM PUBLISHER]

Published
2004

33. Gas puff implosion measurements and modeling.

Author

Moosman, B., Boller, J.R., Commisso, R.J., Hinshelwood, D.D., Mosher, D., Stephanakis, S.J., Weber, B. V., Qi, N., Schein, J., McFarland, M., Prasad, R. R., and Krishnan, M.

Abstract

Two-dimensional interferometric images obtained in gas-puff z-pinch experiments on the Hawk generator are compared with snowplow calculations using the measured gas distribution for various times during the 250-ns implosion. To match the calculated implosion time with the observed implosion time, 88% to 101% of the measured cathode current, adjusted for each shot, is required to implode the snowplow. The snowplow model reproduces the (r,z) shape of the measured 2-D plasma shell at different times during the implosion. The inferred current loss between the measurement location (17-cm upstream of the nozzle) and the z-pinch may be due to vacuum flow resulting from the plasma-opening switch. [ABSTRACT FROM PUBLISHER]

Published
2000

34. Gas puff implosion measurements and modeling

Author

Moosman, B., primary, Boller, J.R., additional, Commisso, R.J., additional, Mosher, D., additional, Stephankis, S.J., additional, Weber, B.V., additional, Young, F.C., additional, Qi, N., additional, Schein, J., additional, Gensler, S., additional, Prasad, R.R., additional, and Krishnan, M., additional

Published
2000
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35. Long conduction time plasma opening switch experiments.

Author

Adler, L.K., Ben-Amar Baranga, A., Greenly, J.B., Hammer, D.A., and Qi, N.

Abstract

This paper includes results of two experiments, one in which the characteristics of a flash board plasma source were determined as a function of space and time using spectroscopic techniques, and the other in which a long conduction time plasma opening switch plasma has been studied before, during and after opening, mainly with the use of optical photography and magnetic probes. The 6cm × 10cm carbon coated flashboard generates a few 1013 ions/cm3, 3–4eV mostly C+ and C++ plasma with a directed velocity away from the flash-board of about 10cm/ /µsec and a transverse spread rate of only 1.5cm/ /µs. When the plasma impinges upon a metal plate placed 10cm away, a substantial build-up of cooler plasma occurs within 2–3cm of the surface. In the opening switch experiment, 5ns optical photographs taken from the side showed a narrow (1–2cm) band of light connecting the anode to the cathode (separated by 9mm) during the conduction phase. The band moved from the current source end of the switch to the load end, where the channel width decreased and the light substantially decreased in the middle of the gap. The maximum dI/ dt into a short circuit load occurred when the light decreased midgap, after which plasma was ejected nonuniformly several cm downstream of the switch region. [ABSTRACT FROM PUBLISHER]

Published
1990

38. X-pinch Plasma As A Point Neutron Source

Author

Mittal, K.C., primary, Kalantar, D.H., additional, Qi, N., additional, Hammer, D.A., additional, Bordonaro, G.J., additional, Dunning, A.J., additional, Gerber, K.A., additional, and Sethjan, J.D., additional

Published
1991
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40. Measurement and Analysis of Continuum Radiation From a Large-Diameter Long Implosion Time Argon Gas Puff Z-Pinch at 6 MA.

Author

Young, F. C., Commisso, Robert J., Murphy, D. P., Apruzese, John P., Mosher, David, Velikovich, Alexander L., Coleman, Philip L., Banister, J. W., Failor, B. H., Levine, J. S., Qi, N., and Sze, H. M.

Subjects
SPECTRUM analysis, RADIATION, ARGON, SPECTROMETERS, ELECTRON temperature, SILICON diodes
Abstract

Time-resolved measurements of the absolute free-bound (FB) continuum spectrum emitted from a 12-cm-diameter argon gas-puff Z-pinch driven at ∼6-MA peak current with 220- to 260-ns implosion times are reported. A crystal spectrometer is used with silicon diode detectors to provide kiloelectronvolt spectral resolution. The energy and absolute-intensity calibration procedures for the spectrometer are described. The slope of the FB continuum is well represented by a decaying exponential spectrum with a single electron temperature from which spatially averaged, time-resolved (Te(t)), and time-integrated ((Te)) electron temperatures are inferred. An expression for the absolute FB continuum, which takes into account recombination onto bare as well as H-like species, is presented and used to infer time-integrated spatially averaged ion densities (ni). The values of (Te) and (ni) are in general agreement with the values of these quantities obtained by using the conventional K-shell line-ratio method. Values of Te(t) peak on the rise of the continuum radiation pulse and gradually decrease during the pulse. The fraction of the total energy radiated in the K-shell that resides in the FB continuum is 6%–10%, and this fraction increases with (ni). Calculated continuum spectra are in agreement with measured spectra. [ABSTRACT FROM AUTHOR]

Published
2006
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49. Radial density and temperature distributors in a Z-pinch inferred from time and space resolved spectra on Decade Quad

Author

Yadlowsky, E.J., primary, Carlson, E.P., additional, Hazelton, R.C., additional, Klepper, C.C., additional, Moschella, J.J., additional, Krishnan, M., additional, Prasad, R., additional, Qi, N., additional, Apruzese, J.P., additional, Davis, J., additional, Thornhill, J.W., additional, Babineau, M., additional, Kenyon, V., additional, Enis, C., additional, and Worley, T., additional

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