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The effect of adding a center jet to Argon gas puff implosions at the Z facility

Harvey-Thompson, Adam J.; Jennings, Christopher A.; Jones, Brent M.; Ampleford, David A.; Hansen, Stephanie B.; Lamppa, Derek C.; Cuneo, M.E.; Reneker, Joseph R.; Johnson, Drew J.; Jones, Michael J.; Moore, N.W.M.; Flanagan, Timothy M.; Mckenney, John M.; Rochau, G.A.; Waisman, E.M.W.; Coverdale, Christine A.; Thornhill, J.W.T.; Giuliani, J.L.G.; Chong, Y.K.C.; Velikovich, A.L.V.; Dasgupta, A.D.; Apruzese, J.P.A.

Abstract not provided.

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TYPE Presentation YEAR 2014
OSTIDOI

Signatures of hot electrons and fluorescence in Mo Kα emission on Z

Physics of Plasmas

Hansen, Stephanie B.; Ampleford, David A.; Cuneo, M.E.; Ouart, N.; Jones, Brent M.; Jennings, C.A.; Dasgupta, A.; Coverdale, Christine A.; Rochau, G.A.; Dunham, Gregory S.; Giuliani, J.L.; Apruzese, J.P.

Recent experiments on the Z accelerator have produced high-energy (17 keV) inner-shell K-alpha emission from molybdenum wire array z-pinches. Extensive absolute power and spectroscopic diagnostics along with collisional-radiative modeling enable detailed investigation into the roles of thermal, hot electron, and fluorescence processes in the production of high-energy x-rays. We show that changing the dimensions of the arrays can impact the proportion of thermal and non-thermal K-shell x-rays. © 2014 AIP Publishing LLC.

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TYPE Conference YEAR 2014
ScopusOSTI

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

AIP Conference Proceedings

Apruzese, J.P.; Jones, Brent M.; Giuliani, J.L.; Ouart, N.D.; Thornhill, J.W.; Harvey-Thompson, Adam J.; Ampleford, David A.; Jennings, C.A.; Hansen, Stephanie B.; Moore, N.W.; Lamppa, Derek C.; Coverdale, C.A.; Cuneo, M.E.; Rochau, G.A.

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 K-shell 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 K-shell x-rays.

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TYPE Conference Poster YEAR 2014
ScopusOSTI

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

AIP Conference Proceedings

Giuliani, J.L.; Thornhill, J.W.; Apruzese, J.P.; Jones, Brent M.; Harvey-Thompson, Adam J.; Ampleford, David A.; Dasgupta, A.; Jennings, C.A.; Hansen, S.B.; Moore, N.W.; Lamppa, D.C.; Coverdale, Christine A.; Cuneo, M.E.; Rochau, G.A.

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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TYPE Conference Poster YEAR 2014
ScopusOSTI

X-ray power and yield measurements at the refurbished Z machine

Review of Scientific Instruments

Jones, Brent M.; Ampleford, David A.; Cuneo, M.E.; Hohlfelder, Robert J.; Jennings, C.A.; Johnson, Drew J.; Jones, Brent M.; Lopez, M.R.; Macarthur, J.; Mills, Jerry A.; Preston, T.; Rochau, G.A.; Savage, Mark E.; Spencer, D.; Sinars, Daniel S.; Porter, J.L.

Advancements have been made in the diagnostic techniques to measure accurately the total radiated x-ray yield and power from z-pinch implosion experiments at the Z machine with high accuracy. The Z machine is capable of outputting 2 MJ and 330 TW of x-ray yield and power, and accurately measuring these quantities is imperative. We will describe work over the past several years which include the development of new diagnostics, improvements to existing diagnostics, and implementation of automated data analysis routines. A set of experiments on the Z machine were conducted in which the load and machine configuration were held constant. During this shot series, it was observed that the total z-pinch x-ray emission power determined from the two common techniques for inferring the x-ray power, a Kimfol filtered x-ray diode diagnostic and the total power and energy diagnostic, gave 449 TW and 323 TW, respectively. Our analysis shows the latter to be the more accurate interpretation. More broadly, the comparison demonstrates the necessity to consider spectral response and field of view when inferring x-ray powers from z-pinch sources. © 2014 AIP Publishing LLC.

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TYPE Journal Article YEAR 2014
ScopusOSTIDOI
Results 126–150 of 273
Results 126–150 of 273