Comparison of a copper foil to a copper wire-array Z pinch at 18 MA

Nash, T. J.; Deeney, C.; Chandler, G. A.; Sinars, Daniel Brian; Cuneo, M. E.; Waisman, E.; Stygar, W. A.; Wenger, D. F.; Speas, Shane; Leeper, R. J.; Seaman, J. F.; McGurn, J.; Torres, J. A.; Jobe, D.; Gilliland, T. L.; Nielsen, D. S.; Hawn, R.; Seaman, Henry B.; Keller, K. L.; Moore, Timothy; Wagoner, T. C.; LePell, P.D.; Lucas, J.; Schroen, D. G.; Russell, C.; Kernaghan, Matthew Doyle

doi:10.1063/1.1796352

Cited by 24 publications

(15 citation statements)

References 16 publications

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“…To some extent, this is similar to the experimental results of the copper wire array and foil with the same mass, in which the array exhibited delayed onset of acceleration and imploded with higher final velocity than the foil. 22 This implies that the appearance of the low-density plasma ͑precursor plasma͒ affects the magnetic field evolution and distribution, which favors the acceleration as a whole and the implosion of the shell. Now we investigate the evolution processes of the plasma shell implosions in detail.…”

Section: The Effects Of the Prefilled Low-density Plasma On The Zmentioning

confidence: 99%

“…10,[15][16][17] It is well known that the instabilities of Z-pinch are suppressed and, in turn, the x-ray power output is dramatically increased if a cylindrical foil liner is replaced by a cylindrical wire-array load consisted of many fine metallic wires. [18][19][20][21][22] The main difference between wire array and foil liner implosions is the appearance of a prolonged wire-array ablation process and the precursor plasma formation in the wire-array Z-pinch. This indirectly demonstrates that the precursor plasma impacts the implosion performance of the wire-array Z-pinch.…”

Section: Introductionmentioning

confidence: 99%

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Numerical studies of the effects of precursor plasma on the performance of wire-array Z-pinches

et al. 2010

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This paper is to numerically investigate, in one dimension, the effects of precursor plasma resulted from wire-array ablation on the performance of its following implosion after the ablation. The wire-array ablation is described by an analytic model, which consists of a rocket model or Sasorov's expression of wire-array mass ablation rate, the evolution equation of magnetic field, and several roughly reasonable assumptions. The following implosion is governed by the radiation magnetohydrodynamics. The implosion processes of wire-array Z-pinch from plasma shells prefilled and un-prefilled by the low-density plasma inside them are studied, and that from the wire-array ablations, which may be changed through varying the ablation time, ablation rate, and ablation velocity V abl , are also simulated. The obtained results reveal that the prefilled low-density plasma and the precursor plasma from the wire-array ablation help to enhance the plasma shell pinch and the final implosion of the wire array, respectively, compared to the pinch of un-prefilled plasma shell. With the same plasma masses, which are distributed in the interior of the array and the shell, and modified Spitzer resistivity, the implosions that start from the wire ablation develop faster than that from the plasma shell with the prefill. If more substance ablates from the wire array before the start of its implosion, the final Z-pinch performance could be better. The Z-pinch plasma is highly magnetized with driven current more than 3 MA.

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Section: The Effects Of the Prefilled Low-density Plasma On The Zmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical studies of the effects of precursor plasma on the performance of wire-array Z-pinches

et al. 2010

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“…as thin as a few hundred atomic spacings. Despite the difficulty in mounting such a shell, Nash et al [58] successfully drove an implosion but with lower performance than the equivalent wire array.…”

Section: Overviewmentioning

confidence: 99%

A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

391

184

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The Z-pinch, perhaps the oldest subject in plasma physics, has achieved a remarkable renaissance in recent years, following a few decades of neglect due to its basically unstable MHD character. Using wire arrays, a significant transition at high wire number led to a great improvement in both compression and uniformity of the Z-pinch. Resulting from this the Z-accelerator at Sandia at 20 MA in 100 ns has produced a powerful, short pulse, soft x-ray source >230 TW for 4.5 ns) at a high efficiency of ∼15%. This has applications to inertial confinement fusion. Several hohlraum designs have been tested. The vacuum hohlraum has demonstrated the control of symmetry of irradiation on a capsule, while the dynamic hohlraum at a higher radiation temperature of 230 eV has compressed a capsule from 2 mm to 0.8 mm diameter with a neutron yield >3 × 10 11 thermal DD neutrons, a record for any capsule implosion. World record ion temperatures of >200 keV have recently been measured in a stainless-steel plasma designed for Kα emission at stagnation, due, it was predicted, to ion-viscous heating associated with the dissipation of fast-growing short wavelength nonlinear MHD instabilities. Direct fusion experiments using deuterium gas-puffs have yielded 3.9×10 13 neutrons with only 5% asymmetry, suggesting for the first time a mainly thermal source. The physics of wire-array implosions is a dominant theme. It is concerned with the transformation of wires to liquid-vapour expanding cores; then the generation of a surrounding plasma corona which carries most of the current, with inward flowing low magnetic Reynolds number jets correlated with axial instabilities on each wire; later an almost constant velocity, snowplough-like implosion occurs during which gaps appear in the cores, leading to stagnation on the axis, and the production of the main soft-x-ray pulse. These studies have been pursued also with smaller facilities in other laboratories around the world. At Imperial College, conical and radial wire arrays have led to highly collimated tungsten plasma jets with a Mach number of >20, allowing laboratory astrophysics experiments to be undertaken. These highlights will be underpinned in this review with the basic physics of Z-pinches including stability, kinetic effects, and finally its applications.

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“…The inter-wire distance appears to be almost twice larger than the anode-cathode gap. or of thin foils Nash et al, 2004! instead of acceleration of the whole mass.…”

Section: Experiments On Staged Accelerationmentioning

confidence: 99%

An inductive scheme of power conditioning at mega-Ampere currents

et al. 2006

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This work describes an inductive energy storage scheme intended for power multiplication at mega-Ampere currents.The key power multiplication element of the scheme is an opening switch generating the voltage of inductive origin. The switch represents an additional volume with magnetically accelerated solid-state or plasma conductor between the generator and the load. Motion of the conductor increases the inductance of the volume. A sufficiently fast increase of this inductance at the end of magnetic energy storage time ensures power multiplication. A critical requirement for the accelerated conductor is the possibility of temporal profiling of the inductance increase. A proof-of-principle experiment at GIT12 shows that such profiling is possible. We suggest a simple analysis of the scheme efficiency and illustrate this analysis for a multi-mega-Ampere class generator. The scheme is alternative to existing inductive energy storage technologies for pulsed-power conditioning at high currents.

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Comparison of a copper foil to a copper wire-array Z pinch at 18 MA

Cited by 24 publications

References 16 publications

Numerical studies of the effects of precursor plasma on the performance of wire-array Z-pinches

Numerical studies of the effects of precursor plasma on the performance of wire-array Z-pinches

A review of the denseZ-pinch

An inductive scheme of power conditioning at mega-Ampere currents

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