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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

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

Larger sized wire arrays on 1.5 MA Z-pinch generator

AIP Conference Proceedings

Safronova, A.S.; Kantsyrev, V.L.; Weller, M.E.; Shlyaptseva, V.V.; Shrestha, I.K.; Esaulov, A.A.; Stafford, A.; Chuvatin, A.S.; Coverdale, Christine A.; Jones, Brent M.

Experiments on the UNR Zebra generator with Load Current Multiplier (LCM) allow for implosions of larger sized wire array loads than at standard current of 1 MA. Advantages of larger sized planar wire array implosions include enhanced energy coupling to plasmas, better diagnostic access to observable plasma regions, and more complex geometries of the wire loads. The experiments with larger sized wire arrays were performed on 1.5 MA Zebra with LCM (the anode-cathode gap was 1 cm, which is half the gap used in the standard mode). In particular, larger sized multi-planar wire arrays had two outer wire planes from mid-atomic-number wires to create a global magnetic field (gmf) and plasma flow between them. A modified central plane with a few Al wires at the edges was put in the middle between outer planes to influence gmf and to create Al plasma flow in the perpendicular direction (to the outer arrays plasma flow). Such modified plane has different number of empty slots: it was increased from 6 up to 10, hence increasing the gap inside the middle plane from 4.9 to 7.7 mm, respectively. Such load configuration allows for more independent study of the flows of L-shell mid-atomic-number plasma (between the outer planes) and K-shell Al plasma (which first fills the gap between the edge wires along the middle plane) and their radiation in space and time. We demonstrate that such configuration produces higher linear radiation yield and electron temperatures as well as advantages of better diagnostics access to observable plasma regions and how the load geometry (size of the gap in the middle plane) influences K-shell Al radiation. In particular, K-shell Al radiation was delayed compared to L-shell mid-atomic-number radiation when the gap in the middle plane was large enough (when the number of empty slots was increased up to ten).

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TYPE Conference Poster YEAR 2014
ScopusOSTI
Results 26–50 of 202
Results 26–50 of 202