Implosion dynamics and radiative characteristics of a high yield structured gas puff load

Levine, Jerrold S.; Banister, J.; Failor, B. H.; Qi, N.; Sze, H.; Velikovich, A. L.; Commisso, R.J.; Davis, J.; Lojewski, D.

doi:10.1063/1.2221660

Cited by 38 publications

(18 citation statements)

References 32 publications

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“…These measurements are consistent with the radiator-stabilizer-pusher model of the jet-innerouter gas puff described by Sze et al 1 in which the jet mass is heated and radiates in the K-shell, while the inner and outer shells remain cooler and produce much less K-shell radiation. Indeed, measurements of Cl dopant K-shell emission reported by Levine et al 2 indicate that most of the Ar K-shell emission is produced by mass that originated in the center jet ͑65%͒, followed by the inner shell ͑30%͒ and the outer shell ͑5%͒. Given the load mass distribution ͑center jet 20%, inner 40%, and outer 40%͒, the relative K-shell yield per unit mass for the inner and outer were only 23% and 4%, respectively, compared to the center jet.…”

Section: Discussionmentioning

confidence: 95%

“…1 The factor of Ϸ2 difference between the hot core and cool blanket FWHM is consistent with the observed 25% K-shell-emitting mass fraction. 2 We have also observed that the XUV emission time history and its time integral are strong functions of the puff gas density and radial density profile. If the puff density is sufficiently high, the puff will not be as highly ionized before the onset of K-shell emission, and a sharp increase in XUV emission will be observed at that time due to strong photoheating of the cool outer blanket.…”

Section: Introductionmentioning

confidence: 91%

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K -shell and extreme ultraviolet spectroscopic signatures of structured Ar puff Z-pinch loads with high K-shell x-ray yield

et al. 2007

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Structured 12-cm-diam Ar gas-puff loads have recently produced Z-pinch implosions with reduced Rayleigh-Taylor instability growth and increased K-shell x-ray yield [H. Sze, J. Banister, B. H. Failor, J. S. Levine, N. Qi, A. L. Velikovich, J. Davis, D. Lojewski, and P. Sincerny, Phys. Rev. Lett. 95, 105001 (2005)]. To better understand the dynamics of these loads, we have measured the extreme ultraviolet (XUV) emission resolved radially, spectrally, and axially. Radial measurements indicated a compressed diameter of ≈3mm, consistent with the observed load inductance change and an imploded-mass consisting of a ≈1.5-mm-diam, hot, K-shell-emitting core and a cooler surrounding blanket. Spectral measurements indicate that, if the load is insufficiently heated, then radiation from the core will rapidly photoheat the outer blanket, producing a strong increase in XUV emission. Also, adding a massive center jet (⩾20% of load mass) increases the rise and fall times of the XUV emission to ⩾40ns, consistent with a more adiabatic compression and heating of the load. Axial measurements show that, despite differences in the XUV and K-shell emission time histories, the K-shell x-ray yield is insensitive to axial variations in load mass.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 91%

K -shell and extreme ultraviolet spectroscopic signatures of structured Ar puff Z-pinch loads with high K-shell x-ray yield

et al. 2007

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“…This technique has lead to the most powerful and efficient plasma radiation source presently available in the laboratory. [27][28][29] Similar experiments with deuterium gas-puff lead in 2007 on the Z accelerator in Sandia have produced 3.7 Â 10 13 DD neutrons (at 2.34 MeV). 30 This result is only comparable with the one very recently obtained on the National Ignition Facility at Livermore of 2.4 Â 10 15 DT neutrons.…”

Section: Introductionmentioning

confidence: 92%

Analytic model for the dynamic Z-pinch

2015

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A model is presented for describing the cylindrical implosion of a shock wave driven by an accelerated piston. It is based in the identification of the acceleration of the shocked mass with the acceleration of the piston. The model yields the separate paths of the piston and the shock. In addition, by considering that the shocked region evolves isentropically, the approximate profiles of all the magnitudes in the shocked region are obtained. The application to the dynamic Z-pinch is presented and the results are compared with the well known snowplow and slug models which are also derived as limiting cases of the present model. The snowplow model is seen to yield a trajectory in between those of the shock and the piston. Instead, the neglect of the inertial effects in the slug model is seen to produce a too fast implosion, and the pressure uniformity is shown to lead to an unphysical instantaneous piston stopping when the shock arrives to the axis. V C 2015 AIP Publishing LLC. [http://dx.

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“…We anticipate that adding a center gas jet will produce a more stable pinched plasma column. [26][27][28] The 12.5 lm Al wire had a mass line density of 3 lg/cm, which is comparable to the 10 lg/cm gas puff. Similar to the process in wire array Z-pinches, there was a solid Al core that did not participate in the implosion.…”

Section: B Ne/ar Implosions With a Wire On The Axismentioning

confidence: 97%

Study of gas-puff Z-pinches on COBRA

Rosenberg

Gourdain

et al. 2014

Physics of Plasmas

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Gas-puff Z-pinch experiments were conducted on the 1 MA, 200 ns pulse duration Cornell Beam Research Accelerator (COBRA) pulsed power generator in order to achieve an understanding of the dynamics and instability development in the imploding and stagnating plasma. The triplenozzle gas-puff valve, pre-ionizer, and load hardware are described. Specific diagnostics for the gas-puff experiments, including a Planar Laser Induced Fluorescence system for measuring the radial neutral density profiles along with a Laser Shearing Interferometer and Laser Wavefront Analyzer for electron density measurements, are also described. The results of a series of experiments using two annular argon (Ar) and/or neon (Ne) gas shells (puff-on-puff) with or without an on-(or near-) axis wire are presented. For all of these experiments, plenum pressures were adjusted to hold the radial mass density profile as similar as possible. Initial implosion stability studies were performed using various combinations of the heavier (Ar) and lighter (Ne) gasses. Implosions with Ne in the outer shell and Ar in the inner were more stable than the opposite arrangement. Current waveforms can be adjusted on COBRA and it was found that the particular shape of the 200 ns current pulse affected on the duration and diameter of the stagnated pinched column and the x-ray yield. V C 2014 AIP Publishing LLC. [http://dx.

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Implosion dynamics and radiative characteristics of a high yield structured gas puff load

Cited by 38 publications

References 32 publications

K -shell and extreme ultraviolet spectroscopic signatures of structured Ar puff Z-pinch loads with high K-shell x-ray yield

K -shell and extreme ultraviolet spectroscopic signatures of structured Ar puff Z-pinch loads with high K-shell x-ray yield

Analytic model for the dynamic Z-pinch

Study of gas-puff Z-pinches on COBRA

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