Two-dimensional radiation MHD modeling assessment of designs for argon gas puff distributions for future experiments on the refurbished Z machine

Thornhill, J. W.; Giuliani, J. L.; Chong, Y. K.; Velikovich, A. L.; Dasgupta, A.; Apruzese, J. P.; Jones, B.; Ampleford, D. J.; Coverdale, C. A.; Jennings, Christopher; Waisman, E.; Lamppa, Derek C.; McKenney, J. L.; Cuneo, M. E.; Krishnan, M.; Coleman, P.L.; Madden, R.; Elliott, K. Wilson

doi:10.1016/j.hedp.2012.03.010

Cited by 21 publications

(8 citation statements)

References 20 publications

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“…(16), (17), and (20) is not difficult. However, we cannot start the integration at the axis, g ¼ 0, which is a singular point of this system that corresponds to the limit ln g !…”

Section: Analytic Developmentmentioning

confidence: 99%

“…Solution for larger g is found by numerical integration of Eqs. (16), (17) together with (20), with initial condition U g 0 ð Þ ¼ U 0 and S g 0 ð Þ ¼ S 0 . The numerical integration proceeds in the direction of increasing g until the trajectory reaches the locus of points representing the post-shock states for strong MHD shocks.…”

Section: Analytic Developmentmentioning

confidence: 99%

“…This is most often done in the post-diction mode, for example with radiation pulse shapes 15 or spectra, 16 but also in the more precarious prediction mode. 17 A third kind of test, which is the focus of the present article, is verification, i.e., comparison of simulation results against an idealized problem with exact solutions. In the gasdynamic case, when currents and magnetic fields are absent, there are a variety of exact solutions suitable for code verification.…”

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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“…(16), (17), and (20) is not difficult. However, we cannot start the integration at the axis, g ¼ 0, which is a singular point of this system that corresponds to the limit ln g !…”

Section: Analytic Developmentmentioning

confidence: 99%

Section: Analytic Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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 doubleshell nozzle of 8 cm diameter [3] was employed to form the load. Based on simulations [4,5], a 1 mg/cm total load mass with inner-to-outer shell mass ratio of 1.6:1 was employed. A Marx charge of 85 kV produced a measured feed current of 16 MA, but significant convolute losses likely resulted in a smaller load current, whose magnitude is the subject of a separate analysis [6].…”

Section: Description Of Experimentsmentioning

confidence: 99%

Diagnostic constraints on the amount of cold mass in imploded argon pinches on Z

Apruzese¹,

Giuliani²,

Ouart³

et al. 2014

AIP Conference Proceedings

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Abstract. The refurbished Z machine at Sandia National Laboratories has been successfully configured to drive gas-puff Z pinches. A series of experiments using Ar loads produced K-shell yields of 330 ± 9% kJ, with highly reproducible Kshell spectra and power pulses. Using spectroscopic and power data, we are able to constrain the properties of both the cold, non-K-shell radiating mass as well as the hot K-shell component of the pinch plasma. As in previous gas-puff shots on the original version of Z, only about 1/4 to 1/3 of the load mass was heated to temperatures sufficient to produce Kshell x-rays.

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“…[3] is a follow-up to pre-shot calculations of Ref. [4] designed to determine, among several choices, the optimal total mass loading and initial density profile.…”

Section: Introductionmentioning

confidence: 99%

Two dimensional RMHD modeling of effective ion temperatures in recent ZR argon experiments

Giuliani¹,

Thornhill²,

Apruzese³

et al. 2014

AIP Conference Proceedings

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Abstract. Radiation magnetohydrodynamic r-z simulations are performed of recent Ar shots on the refurbished Z generator to examine the effective ion temperature as determined from the observed line width of the He-γ line. While many global radiation properties can be matched to experimental results, the Doppler shifts due to velocity gradients at stagnation cannot reproduce the large experimentally determined width corresponding to an effective ion temperature of 50 keV. Ion viscous heating or magnetic bubbles are considered, but understanding the width remains an unsolved challenge.

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Two-dimensional radiation MHD modeling assessment of designs for argon gas puff distributions for future experiments on the refurbished Z machine

Cited by 21 publications

References 20 publications

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

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

Diagnostic constraints on the amount of cold mass in imploded argon pinches on Z

Two dimensional RMHD modeling of effective ion temperatures in recent ZR argon experiments

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