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Determination of pressure and density of shocklessly compressed beryllium from x-ray radiography of a magnetically driven cylindrical liner implosion

AIP Conference Proceedings

Lemke, R.W.; Martin, M.R.; McBride, Ryan D.; Davis, Jean-Paul D.; Knudson, Marcus D.; Sinars, Daniel S.; Smith, Ian C.; Savage, Mark E.; Stygar, William A.; Killebrew, K.; Flicker, Dawn G.; Herrmann, Mark H.

We describe a technique for measuring the pressure and density of a metallic solid, shocklessly compressed to multi-megabar pressure, through x-ray radiography of a magnetically driven, cylindrical liner implosion. Shockless compression of the liner produces material states that correspond approximately to the principal compression isentrope (quasi-isentrope). This technique is used to determine the principal quasi-isentrope of solid beryllium to a peak pressure of 2.4 Mbar from x-ray images of a high current (20 MA), fast (∼100 ns) liner implosion. © 2012 American Institute of Physics.

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TYPE Conference YEAR 2012
ScopusOSTI

Solid liner implosions on Z for producing multi-megabar, shockless compressions

Physics of Plasmas

Martin, M.R.; Lemke, Raymond W.; McBride, Ryan D.; Davis, Jean-Paul D.; Dolan, Daniel H.; Knudson, Marcus D.; Cochrane, K.R.; Sinars, Daniel S.; Smith, Ian C.; Savage, Mark E.; Stygar, William A.; Killebrew, K.; Flicker, Dawn G.; Herrmann, Mark H.

Current pulse shaping techniques, originally developed for planar dynamic material experiments on the Z-machine [M. K. Matzen, Phys. Plasmas 12, 055503 (2005)], are adapted to the design of controlled cylindrical liner implosions. By driving these targets with a current pulse shape that prevents shock formation inside the liner, shock heating is avoided along with the corresponding decrease in electrical conductivity ahead of the magnetic diffusion wave penetrating the liner. This results in an imploding liner with a significant amount of its mass in the solid phase and at multi-megabar pressures. Pressures in the solid region of a shaped pulse driven beryllium liner fielded on the Z-machine are inferred to 5.5 Mbar, while simulations suggest implosion velocities greater than 50 kms-1. These solid liner experiments are diagnosed with multi-frame monochromatic x-ray backlighting which is used to infer the material density and pressure. This work has led to a new platform on the Z-machine that can be used to perform off-Hugoniot measurements at higher pressures than are accessible through magnetically driven planar geometries. © 2012 American Institute of Physics.

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TYPE Journal Article YEAR 2012
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Impact of time-varying loads on the programmable pulsed power driver called genesis

Digest of Technical Papers-IEEE International Pulsed Power Conference

Glover, Steven F.; Davis, Jean-Paul D.; Schneider, Larry X.; Reed, Kim W.; Pena, Gary P.; Hall, Clint A.; Hanshaw, Heath L.; Hickman, Randy J.; Hodge, K.C.; Lemke, Raymond W.; Lehr, J.M.; Lucero, D.J.; McDaniel, Dillon H.; Puissant, J.G.; Rudys, Joseph M.; Sceiford, Matthew S.; Tullar, S.J.; Van De Valde, D.M.; White, F.E.; Warne, Larry K.; Coats, Rebecca S.; Johnson, William Arthur.

The success of dynamic materials properties research at Sandia National Laboratories has led to research into ultra-low impedance, compact pulsed power systems capable of multi-MA shaped current pulses with rise times ranging from 220-500 ns. The Genesis design consists of two hundred and forty 200 kV, 80 kA modules connected in parallel to a solid dielectric disk transmission line and is capable of producing 280 kbar of magnetic pressure (>500 kbar pressure in high Z materials) in a 1.75 nH, 20 mm wide stripline load. Stripline loads operating under these conditions expand during the experiment resulting in a time-varying load that can impact the performance and lifetime of the system. This paper provides analysis of time-varying stripline loads and the impact of these loads on system performance. Further, an approach to reduce dielectric stress levels through active damping is presented as a means to increase system reliability and lifetime. © 2011 IEEE.

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TYPE Conference YEAR 2011
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Status of genesis a 5 MA programmable pulsed power driver

Digest of Technical Papers-IEEE International Pulsed Power Conference

Glover, Steven F.; White, F.E.; Foster, P.J.; Lucero, D.J.; Schneider, Larry X.; Reed, Kim W.; Pena, Gary P.; Davis, Jean-Paul D.; Hall, Clint A.; Hickman, Randy J.; Hodge, K.C.; Lemke, Raymond W.; Lehr, J.M.; McDaniel, Dillon H.; Puissant, J.G.; Rudys, Joseph M.; Sceiford, Matthew S.; Tullar, S.J.; Van De Valde, D.M.

Genesis is a compact pulsed power platform designed by Sandia National Laboratories to generate precision shaped multi-MA current waves with a rise time of 200-500 ns. In this system, two hundred and forty, 200 kV, 80 kA modules are selectively triggered to produce 280 kbar of magnetic pressure (>500 kbar pressure in high Z materials) in a stripline load for dynamic materials properties research. This new capability incorporates the use of solid dielectrics to reduce system inductance and size, programmable current shaping, and gas switches that must perform over a large range of operating conditions. Research has continued on this technology base with a focus on demonstrating the integrated performance of key concepts into a Genesis-like prototype called Protogen. Protogen measures approximately 1.4 m by 1.4 m and is designed to hold twelve Genesis modules. A fixed inductance load will allow rep-rate operation for component reliability and system lifetime experiments at the extreme electric field operating conditions expected in Genesis. © 2011 IEEE.

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TYPE Conference YEAR 2011
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Results 51–75 of 113
Results 51–75 of 113