Soft x-ray measurements of <i>z</i>-pinch-driven vacuum hohlraums

Baker, K. L.; Porter, J. L.; Ruggles, L. E.; Chandler, G. A.; Deeney, C.; Vargas, M.; Moats, A. R.; Struve, K.W.; Torres, J. A.; McGurn, J.; Simpson, W. W.; Fehl, D. L.; Chrien, R. E.; Matuska, W.; Idzorek, G. C.

doi:10.1063/1.124509

Cited by 23 publications

(7 citation statements)

References 12 publications

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“…An important feature of this is that the energy E to be provided to an inertially confined sphere is proportional to n −2 i where n i is the ion density. This can be seen as follows E = 4 3 πR 3 • 3n i eT i (7.19) and the Lawson product n i τ for inertial confinement is n i R/c s , but now multiplied by (M L /M) 1/2 where M L is the sum of the liner and plasma mass M and c s is the ion sound speed. Thus E is given by…”

Section: Magnetized Target Fusion (Mtf)mentioning

confidence: 99%

A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

386

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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Section: Magnetized Target Fusion (Mtf)mentioning

confidence: 99%

A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

386

184

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“…Preliminary hohlraum experiments have yielded a radiation temperature in excess of 150 eV in a static hohlraum configuration. 66 For the planned X-1 accelerator with an x-ray yield of 10 MJ a thermonuclear yield in the 1 GJ range should be possible from a capsule in a hohlraum cavity fed axially each side from two Z pinches. 67 The more compact dynamic hohlraum, formed inside the wire arrays by stagnating onto a coated foam is also now yielding radiation temperatures in the 150-200 eV range.…”

Section: Summary and The Futurementioning

confidence: 99%

The past, present, and future of Z pinches

et al. 2000

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The Z pinch is enjoying a renaissance as the world's most powerful yet efficient soft x-ray source which can energize large volume hohlraums for indirectly driven inertial confinement fusion. It has the advantages of being efficient and having high energy and power density. Its early history will be traced from the 18th century to the present day. The most notable feature of the Z pinch is its instability. The various regimes of stability analysis will be reviewed, including resistive and finite ion Larmor radius effects. Work in the last 10 years on single fibres, especially of cryogenic deuterium, gave neutrons that were of the same origin, namely, beam-plasma interactions, as reported by Kurchatov. The renaissance has come about through the implosion of arrays of fine wires. Research at Sandia National Laboratory has shown that by using more and finer wires, the x-ray radiation emitted at stagnation increased in power and decreased in pulse width. The understanding of these results has been advanced considerably by theory, simulation and smaller-scale, well diagnosed experiments showing the early uncorrelated mϭ0 instabilities on each wire, the inward jetting of plasma to the axis, the global Rayleigh-Taylor instability and the mitigating effect of nested arrays.

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“…The peak temperature given by the silicon detector is 140 eV, about 2% higher than the TGS results without the PIN detectors at the C and O edges (137 eV) and 5% higher than the fits including these detectors (133 eV). Other measurements [32][33][34]38] for these hohlraums give a peak re-emission temperature of 140 eV obtained from bolometer [70] normalized filtered x-ray diode (XRD) measurements [71].…”

Section: Primary Hohlraum Energeticsmentioning

confidence: 99%

“…These re-emission temperatures therefore correspond to radiation flux temperatures (e.g. the temperature of the radiation field incident on the hohlraum walls) of T R = T w /α 0.25 = 141 to 145 ± 7 eV from the TGS, 148 ± 7 eV from the filtered silicon diodes and 148 eV from the XRD/bolometer measurements [33,34]. The radiation temperature is higher than the wall re-emission temperature because each element on the hohlraum wall sees a flux that is a combination of 80% wall re-emission spectra (peak ∼133 to 140 eV) and 20% pinch source power (peak brightness temperature ∼165 to 200 eV, see figure 15, section 4).…”

Section: Primary Hohlraum Energeticsmentioning

confidence: 99%

Progress in symmetric ICF capsule implosions and wire-arrayz-pinch source physics for double-pinch-driven hohlraums

Cuneo

Vesey

Bennett

et al. 2006

Plasma Phys. Control. Fusion

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Over the last several years, rapid progress has been made evaluating the doublez-pinch indirect-drive, inertial confinement fusion (ICF) high-yield target concept (Hammer et al 1999 Phys. Plasmas 6 2129). We have demonstrated efficient coupling of radiation from two wire-array-driven primary hohlraums to a secondary hohlraum that is large enough to drive a high yield ICF capsule. The secondary hohlraum is irradiated from two sides by z-pinches to produce low odd-mode radiation asymmetry. This double-pinch source is driven from a single electrical power feed (Cuneo et al 2002 Phys. Rev. Lett. 88 215004) on the 20 MA Z accelerator. The double z-pinch has imploded ICF capsules with even-mode radiation symmetry of 3.1 ± 1.4% and to high capsule radial convergence ratios of 14-21 (

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Soft x-ray measurements of z-pinch-driven vacuum hohlraums

Cited by 23 publications

References 12 publications

A review of the denseZ-pinch

A review of the denseZ-pinch

The past, present, and future of Z pinches

Progress in symmetric ICF capsule implosions and wire-arrayz-pinch source physics for double-pinch-driven hohlraums

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