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Modified 3D-helix-like instability structure for imploding Z-pinch liners that are premagnetized with a uniform axial field

Awe, Thomas J.; Jennings, Christopher A.; McBride, Ryan D.; Cuneo, M.E.; Lamppa, Derek C.; Martin, Matthew; Rovang, Dean C.; Sinars, Daniel S.; Slutz, Stephen A.; Owen, Albert C.; Gomez, Matthew R.; Hansen, Stephanie B.; Harding, Eric H.; Herrmann, Mark H.; Jones, Michael J.; Knapp, Patrick K.; Mckenney, John M.; Peterson, Kyle J.; Robertson, Grafton K.; Rochau, G.A.; Savage, Mark E.; Schmit, Paul S.; Sefkow, Adam B.; Stygar, William A.; Vesey, Roger A.; Yu, Edmund Y.; Tomlinson, Kurt T.; Schroen, Diana G.

Abstract not provided.

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TYPE Presentation YEAR 2014
OSTI

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

Modified helix-like instability structure on imploding z-pinch liners that are pre-imposed with a uniform axial magnetic field

Physics of Plasmas

Awe, Thomas J.; Owen, Albert C.; Gomez, Matthew R.; Hansen, Stephanie B.; Herrmann, Mark H.; Jones, Michael J.; Mckenney, John M.; Robertson, Grafton K.; Rochau, G.A.; Savage, Mark E.; Stygar, William A.; Jennings, Christopher A.; McBride, Ryan D.; Lamppa, Derek C.; Martin, Matthew; Rovang, Dean C.; Sinars, Daniel S.; Slutz, Stephen A.; Cuneo, M.E.

Abstract not provided.

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TYPE Journal Article YEAR 2014
OSTIDOI

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

Observations of Modified Three-Dimensional Instability Structure for Imploding z -Pinch Liners that are Premagnetized with an Axial Field

Physical Review Letters

McBride, Ryan D.; Gomez, Matthew R.; Hansen, Stephanie B.; Herrmann, Mark H.; Mckenney, John M.; Robertson, Grafton K.; Rochau, G.A.; Savage, Mark E.; Stygar, William A.; Jennings, Christopher A.; Lamppa, Derek C.; Martin, Matthew; Rovang, Dean C.; Slutz, Stephen A.; Cuneo, M.E.; Owen, Albert C.; Sinars, Daniel S.

Novel experimental data are reported that reveal helical instability formation on imploding z -pinch liners that are premagnetized with an axial field. Such instabilities differ dramatically from the mostly azimuthally symmetric instabilities that form on unmagnetized liners. The helical structure persists at nearly constant pitch as the liner implodes. This is surprising since, at the liner surface, the azimuthal drive field presumably dwarfs the axial field for all but the earliest stages of the experiment. These fundamentally 3D results provide a unique and challenging test for 3D-magnetohydrodynamics simulations.

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TYPE Journal Article YEAR 2013
OSTIDOI

Conceptual designs of 300-TW and 800-TW pulsed-power accelerators

Stygar, William A.; Fowler, William E.; Gomez, Matthew R.; Harmon, Roger L.; Herrmann, Mark H.; Huber, Dale L.; Hutsel, Brian T.; Bailey, James E.; Jones, Michael J.; Jones, Peter A.; Leckbee, Joshua L.; Lee, James R.; Lewis, Scot A.; Long, Finis W.; Lopez, Mike R.; Lucero, Diego J.; Matzen, M.K.; Mazarakis, Michael G.; McBride, Ryan D.; McKee, George R.; Nakhleh, Charles N.; Owen, Albert C.; Rochau, G.A.; Savage, Mark E.; Schwarz, Jens S.; Sefkow, Adam B.; Sinars, Daniel S.; Stoltzfus, Brian S.; Vesey, Roger A.; Wakeland, P.; Cuneo, M.E.; Flicker, Dawn G.; Focia, Ronald J.

Abstract not provided.

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TYPE Conference YEAR 2013
OSTI

Integration of MHD load models with circuit representations the Z generator

Ampleford, David A.; Savage, Mark E.; Moore, James M.; Jones, Brent M.; McBride, Ryan D.; Bailey, James E.; Jones, Michael J.; Gomez, Matthew R.; Cuneo, M.E.; Nakhleh, Charles N.; Stygar, William A.

MHD models of imploding loads fielded on the Z accelerator are typically driven by reduced or simplified circuit representations of the generator. The performance of many of the imploding loads is critically dependent on the current and power delivered to them, so may be strongly influenced by the generators response to their implosion. Current losses diagnosed in the transmission lines approaching the load are further known to limit the energy delivery, while exhibiting some load dependence. Through comparing the convolute performance of a wide variety of short pulse Z loads we parameterize a convolute loss resistance applicable between different experiments. We incorporate this, and other current loss terms into a transmission line representation of the Z vacuum section. We then apply this model to study the current delivery to a wide variety of wire array and MagLif style liner loads.

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TYPE SAND Report YEAR 2013
OSTIDOI

Architecture, implementation, and testing of a multiple-shell gas injection system for high current implosions on the Z accelerator

Review of Scientific Instruments

Strizic, Thomas S.; Johnson, Drew J.; Cunningham, Paul C.; Johns, Owen J.; Vigil, Marcelino V.; Jones, Brent M.; Ampleford, David A.; Savage, Mark E.; Cuneo, M.E.; Jones, Michael J.; Lamppa, Derek C.; Mckenney, John M.

Tests are ongoing to conduct ~20 MA z-pinch implosions on the Z accelerator at Sandia National Laboratory using Ar, Kr, and D2 gas puffs as the imploding loads. The relatively high cost of operations on a machine of this scale imposes stringent requirements on the functionality, reliability, and safety of gas puff hardware. Here we describe the development of a prototype gas puff system including the multiple-shell nozzles, electromagnetic drivers for each nozzle's valve, a UV pre-ionizer, and an inductive isolator to isolate the ~2.4 MV machine voltage pulse present at the gas load from the necessary electrical and fluid connections made to the puff system from outside the Z vacuum chamber. This paper shows how the assembly couples to the overall Z system and presents data taken to validate the functionality of the overall system.

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TYPE Journal Article YEAR 2013
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Results 101–150 of 365
Results 101–150 of 365