Doppler effects on 3-D non-LTE radiation transport and emission spectra

Hansen, Stephanie B.; Giuliani, J. L.; Apruzese, J. P.; Thornhill, J. W.; Scott, H. A.; Ampleford, D. J.; Jennings, Christopher; Coverdale, C. A.; Cuneo, M. E.; Rochau, Gregory A.; Bailey, James E.; Dasgupta, A.; Clark, R. W.; Davis, J.

doi:10.1016/j.hedp.2011.06.002

Cited by 14 publications

(8 citation statements)

References 36 publications

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“…However, none of the numerical codes studied here solve a pressure equation exactly as in Eq. (5). The Athena and the internal NRL codes solve the total energy equation in conservation form, rather than the pressure Eq.…”

Section: Discussionmentioning

confidence: 99%

“…However, understanding how the physical processes affect the output requires numerical simulation because of the non-linear interaction between the driving circuit, 1 ablation in the case of wire array loads, 2 magnetohydrodynamics (MHD), 3 non-local thermodynamic equilibrium population kinetics, 4 and radiation transport. 5 Simulations combining these features to varying levels of detail have been performed in one dimension (1D) radial, 6,7 2D RÀZ, 3,8-10 2D XÀY, 11,12 3D cylindrical, 13 and 3D Cartesian 14 coordinates.…”

Section: Introductionmentioning

confidence: 99%

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Exact self-similar solutions for the magnetized Noh Z pinch problem

Velikovich

Giuliani

Zalesak³

et al. 2012

Physics of Plasmas

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A self-similar solution is derived for a radially imploding cylindrical plasma with an embedded, azimuthal magnetic field. The plasma stagnates through a strong, outward propagating shock wave of constant velocity. This analysis is an extension of the classic Noh gasdynamics problem to its ideal magnetohydrodynamics (MHD) counterpart. The present exact solution is especially suitable as a test for MHD codes designed to simulate linear Z pinches. To demonstrate the application of the new solution to code verification, simulation results from the cylindrical RÀZ version of Mach2 and the 3D Cartesian code Athena are compared against the analytic solution. Alternative routines from the default ones in Athena lead to significant improvement of the results, thereby demonstrating the utility of the self-similar solution for verification.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Exact self-similar solutions for the magnetized Noh Z pinch problem

Velikovich

Giuliani

Zalesak³

et al. 2012

Physics of Plasmas

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“…We also note that analysis by Hansen et al [19] of time-gated K-and L-shell spectra from the same 20-mm-tall Cu wire-array experiment (Z shot 1975) plausibly suggests electron temperature up to 3 keV in the stagnating plasma near the pinch axis (and indeed gradients in electron temperature, density, and velocity were all inferred). Time-dependent behavior of the plasma conditions and spatial gradients must also be considered in developing a detailed picture of z-pinch radiation generation.…”

Section: Resultsmentioning

confidence: 52%

“…While Cu K-shell emission is typically generated only as the plasma stagnates on axis, run-in radiation in the Cu L shell is seen during the final stages of the implosion on Z. Copper and nickel L-shell lines can also be used to diagnose the plasma conditions as has been done for the 20-mm-tall experiment in [19] and [22]; however, here, we focus on Doppler splitting in Ne-like Cu 2p-3s transitions (referred to here as Cu 3F and 3G lines). The radially-resolved, time-gated spectroscopic data are shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Wire-Array Z-Pinch Length Variations for K-Shell X-Ray Generation on Z

Ampleford

Jennings

Waisman

et al. 2015

IEEE Trans. Plasma Sci.

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In developing stainless-steel (SS) and copper wire-array X-ray sources on the Z machine, we consider the optimization of K-shell yield as a function of load height. Theory, numerical modeling, and experimental data suggest that an optimum exists corresponding to a tradeoff between the increase in radiating mass and the decrease in coupled current with increasing pinch height. A typical load height of 20 mm used on many previous Z wire-array X-ray sources is found to be near optimal for K-shell yield production in SS and copper implosions. Electrical data, pinhole imaging, and spectroscopy are used to study plasma conditions in wire-array z pinches corresponding to the variation in K-shell power and yield per unit length as the pinch height is changed from 12 to 24 mm.

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“…However, it is still a work in progress. Recently, Hansen improved the model near the plasma vacuum interface by using a set of rays that are weighted by intensity [15].…”

Section: Mach2 and Tcre Modelsmentioning

confidence: 99%