Publications

Rambo, Patrick K.; Galloway, B.R.; Schwarz, Jens S.; Geissel, Matthias G.; Schollmeier, Marius; Kimmel, Mark W.; Field, Ella S.; Kletecka, Damon E.; Speas, Christopher S.; Shores, Jonathon S.; Johnson, Drew J.; Georgeson, Jeffrey K.; Smith, Ian C.; Porter, John L.

Abstract not provided.

Johnson, Drew J.; Lamppa, Derek C.; Jones, Michael J.

Abstract not provided.

Bliss, David E.; Myers, Clayton E.; Jones, Michael J.; Baker, J.L.; Austin, Kevin N.; Bettnecourt, R &.; Bliss, E.; Celeste, J.C.; Celliers, P.C.; Clancy, T.C.; Cohen, S.; Crosley, M.C.; Datte, P.D.; Erskine, D.E.; Fratanduono, D.E.; Frieders, G.F.; Galbraith, J.G.; Hammer, J.H.; Hess, Mark H.; Jackson, J.; Jennings, Christopher A.; Johnson, Drew J.; Koen, D.K.; Lusk, J.L.; Martinez, A.M.; Massey, W.M.; McCarville, T.J.; McDonald, R.; McLean, H.M.; Raman, K.S.; Rodriguez, S.R.; Spencer, Decker C.; Springer, P.S.; de Dios, G.V.; Wong, J.W.

Abstract not provided.

Hohlfelder, Robert J.; Johnson, Drew J.; Lombrozo, Aaron C.; Radovich, S.; Jones, Michael J.

Abstract not provided.

Rambo, Patrick K.; Galloway, B.R.; Schwarz, Jens S.; Geissel, Matthias G.; Schollmeier, Marius; Kimmel, Mark W.; Field, Ella S.; Kletecka, Damon E.; Speas, Christopher S.; Shores, Jonathon S.; Johnson, Drew J.; Georgeson, Jeffrey K.; Smith, Ian C.; Porter, John L.

Abstract not provided.

Ampleford, David A.; Fein, Jeffrey R.; Vogel, J.K.V.; Kozioziemski, B.J.; Walton, C.C.W.; Wu, Ming W.; Ball, Christopher R.; A. Ames, J.A.; Bell, P.B.; Bourdon, Christopher B.; D. Bradley, R.B.; Dunham, Gregory S.; Gard, Paul D.; Johnson, Drew J.; Kilaru, K.K.; Lake, Patrick W.; Maurer, A.; Nielsen-Weber, Linda B.; Pickworth, L.A.; Pivovaroff, M.J.; Ramsey, B.R.; Roberts, O.J.R.; Sullivan, Michael A.; Rochau, G.A.

Abstract not provided.

White, William M.; Savage, Mark E.; McCarthy, Matthew M.; Divett, Samuel J.; Roundy, Shane W.; Spencer, Decker C.; Lombrozo, Aaron C.; Speas, Robert J.; Jojola, Alfred D.; Kamm, Ryan J.; Mignon, Jim P.; Porter, Spencer M.; Salas, W.Z.S.; Radovich, S.; Georgeson, Jeffrey K.; Cortez, Levi C.; Ploor, Stephen P.; Johnson, Drew J.; Wood, Steven L.; Rathbun, John R.

Abstract not provided.

Ball, Christopher R.; Ulmen, Benjamin A.; Cap, Jerome S.; Maurer, A.; Sullivan, Michael A.; Spencer, Decker C.; Johnson, Drew J.; Bourdon, Christopher B.

Abstract not provided.

Ball, Christopher R.; Ampleford, David A.; Gard, Paul D.; Maurer, A.; Bourdon, Christopher B.; Fein, Jeffrey R.; Wu, Ming W.; Lake, Patrick W.; Nielsen-Weber, Linda B.; Dunham, Gregory S.; Johnson, Drew J.; Johns, Owen J.; Sullivan, Michael A.; Kirtley, Christopher K.; Kozioziemski, B.J.; Pickworth, L.A.P.; Vogel, J.K.V.; Pivovaroff, M.JP.; Walton, C.C.W.; Ayers, J.A.; Bell, P.B.; Ramsey, B.R.; Romaine, S.R.

Abstract not provided.

Johnson, Drew J.; Lamppa, Derek C.; Jones, Michael J.; Radovich, S.

Abstract not provided.

Radovich, S.; Jones, Michael J.; Johnson, Drew J.; Lombrozo, Aaron C.; Hohlfelder, Robert J.; Yocom, Mark Y.; Ploor, Stephen P.; Preston, Thaddeus E.; Mills, Jerry A.

Abstract not provided.

Lombrozo, Aaron C.; Jones, Michael J.; Johnson, Drew J.; Mills, Jerry A.; Radovich, S.; Shores, Jonathon S.; Smith, Ian C.

Abstract not provided.

IEEE Transactions on Plasma Science

Thornhill, J.W.; Giuliani, John L.; Jones, Brent M.; Apruzese, John P.; Dasgupta, Arati; Chong, Young K.; Harvey-Thompson, Adam J.; Ampleford, David A.; Hansen, Stephanie B.; Coverdale, Christine A.; Jennings, Christopher A.; Rochau, G.A.; Cuneo, M.E.; Lamppa, Derek C.; Johnson, Drew J.; Jones, Michael J.; Moore, Nathan W.; Waisman, Eduardo M.; Krishnan, Mahadevan; Coleman, Philip L.

By varying current-loss circuit parameters, the Mach2-tabular collisional radiative equilibrium 2-D radiation magnetohydrodynamic model was tuned to reproduce the radiative and electrical properties of three recent argon gas-puff experiments (same initial conditions) performed on the Z machine at Sandia National Laboratories. The model indicates that there were current losses occurring near or within the diode region of the Z machine during the stagnation phase of the implosion. The 'good' simulation reproduces the experimental K-shell powers, K-shell yields, total powers, percentage of emission radiated in α lines, size of the K-shell emission region, and the average electron temperature near the time-of-peak K-shell power. The calculated atomic populations, ion temperatures, and radial velocities are used as input to a detailed multifrequency ray-trace radiation transport model that includes the Doppler effect. This model is employed to construct time-, space-, and energy-resolved synthetic spectra. The role the Doppler effect likely plays in the experiments is demonstrated by comparing synthetic spectra generated with and without this effect.

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, Nathan W.; Flanagan, Timothy M.; Mckenney, John M.; Rochau, G.A.; Waisman, Eduardo M.; Coverdale, Christine A.; Apruzese, J.P.A.; Thornhill, J.W.T.; Giuliani, J.L.G.

Abstract not provided.

Physics of Plasmas

Jones, Brent M.; Apruzese, J.P.; Harvey-Thompson, Adam J.; Ampleford, David A.; Jennings, C.A.; Hansen, Stephanie B.; Moore, Nathan W.; Lamppa, Derek C.; Johnson, Drew J.; Jones, Brent M.; Waisman, Eduardo M.; Coverdale, Christine A.; Cuneo, M.E.; Rochau, G.A.; Giuliani, J.L.; Thornhill, J.W.; Ouart, N.D.; Chong, Y.K.; Velikovich, A.L.; Dasgupta, A.; Krishnan, M.; Coleman, P.L.

Argon gas puffs have produced 330kJ ± 9% of x-ray radiation above 3keV photon energy in fast z-pinch implosions, with remarkably reproducible K-shell spectra and power pulses. This reproducibility in x-ray production is particularly significant in light of the variations in instability evolution observed between experiments. Soft x-ray power measurements and K-shell line ratios from a time-resolved spectrum at peak x-ray power suggest that plasma gradients in these high-mass pinches may limit the K-shell radiating mass, K-shell power, and K-shell yield from high-current gas puffs.

Review of Scientific Instruments

Rovang, Dean C.; Lamppa, Derek C.; Cuneo, M.E.; Owen, A.C.; Mckenney, John M.; Johnson, Drew J.; Radovich, S.; Kaye, Ronald J.; McBride, Ryan D.; Alexander, Charles S.; Awe, T.J.; Slutz, S.A.; Sefkow, Adam B.; Haill, Thomas A.; Jones, Peter A.; Argo, J.W.; Dalton, D.G.; Robertson, Grafton K.; Waisman, Eduardo M.; Sinars, Daniel S.; Meissner, J.; Milhous, M.; Nguyen, D.N.; Mielke, C.H.

Sandia has successfully integrated the capability to apply uniform, high magnetic fields (10-30 T) to high energy density experiments on the Z facility. This system uses an 8-mF, 15-kV capacitor bank to drive large-bore (5 cm diameter), high-inductance (1-3 mH) multi-turn, multi-layer electromagnets that slowly magnetize the conductive targets used on Z over several milliseconds (time to peak field of 2-7 ms). This system was commissioned in February 2013 and has been used successfully to magnetize more than 30 experiments up to 10 T that have produced exciting and surprising physics results. These experiments used split-magnet topologies to maintain diagnostic lines of sight to the target. We describe the design, integration, and operation of the pulsed coil system into the challenging and harsh environment of the Z Machine. We also describe our plans and designs for achieving fields up to 20 T with a reduced-gap split-magnet configuration, and up to 30 T with a solid magnet configuration in pursuit of the Magnetized Liner Inertial Fusion concept.

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.

Harvey-Thompson, Adam J.; Jones, Michael J.; Moore, Nathan W.; Flanagan, Timothy M.; Mckenney, John M.; Coverdale, Christine A.; Coverdale, Christine A.; Jennings, Christopher A.; Jones, Brent M.; Ampleford, David A.; Hansen, Stephanie B.; Lamppa, Derek C.; Cuneo, M.E.; Reneker, Joseph R.; Johnson, Drew J.

Abstract not provided.

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.

IEEE Transactions on Plasma Science

Jones, Brent M.; Jennings, Christopher A.; Harvey-Thompson, Adam J.; Ampleford, David A.; Hansen, Stephanie B.; Lamppa, Derek C.; Cuneo, M.E.; Strizic, Thomas S.; Johnson, Drew J.; Jones, Michael J.; Moore, Nathan W.; Flanagan, Timothy M.; Mckenney, John M.; Coverdale, Christine A.

Abstract not provided.

Jones, Brent M.; Jennings, Christopher A.; Harvey-Thompson, Adam J.; Ampleford, David A.; Hansen, Stephanie B.; Lamppa, Derek C.; Cuneo, M.E.; Strizic, Thomas S.; Johnson, Drew J.; Jones, Michael J.; Moore, Nathan W.; Flanagan, Timothy M.; Mckenney, John M.; Coverdale, Christine A.

Abstract not provided.

Jones, Brent M.; Hansen, Stephanie B.; Jennings, Christopher A.; Ampleford, David A.; Cuneo, M.E.; Rochau, G.A.; Bailey, James E.; Dunham, Gregory S.; Coverdale, Christine A.; Lamppa, Derek C.; Strizic, Thomas S.; Johnson, Drew J.; Jones, Michael J.; Mckenney, John M.

Abstract not provided.

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.

Jones, Brent M.; Lamppa, Derek C.; Hansen, Stephanie B.; Jennings, Christopher A.; Ampleford, David A.; Cuneo, M.E.; Strizic, Thomas S.; Johnson, Drew J.; Jones, Michael J.; Mckenney, John M.; Moore, Nathan W.; Harvey-Thompson, Adam J.; Coverdale, Christine A.

Abstract not provided.

Proposed for publication in Review of Scientific Instruments.

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.; Strizic, Thomas S.

Abstract not provided.