High yield inertial confinement fusion target design for a <i>z</i>-pinch-driven hohlraum

Hammer, J.H.; Tabak, M.; Wilks, S. C.; Lindl, J. D.; Bailey, David; Rambo, P. W.; Toor, A.; Zimmerman, G. B.; Porter, J. L.

doi:10.1063/1.873464

Cited by 144 publications

(79 citation statements)

References 7 publications

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“…Of particular interest were vacuum hohlraums where the collapsing pinch drives an enclosing hohlraum, leading to the possibility that these could be a candidates for indirect drive [9]. Key parts of the concept were to place pinches in primary hohlraums, on each end of a secondary hohlraum containing the capsule, with a Faraday cage barrier between hohlraums.…”

Section: Pulsed Power Hohlraum-driven Fusionmentioning

confidence: 99%

Alternative Approaches to High Energy Density Fusion

Hammer¹

2016

Edward Teller Lectures

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Abstract. This paper explores selected approaches to High Energy Density (HED) fusion, beginning with discussion of ignition requirements at the National Ignition Facility (NIF). The needed improvements to achieve ignition are closely tied to the ability to concentrate energy in the implosion, manifested in the stagnation pressure, P stag . The energy that must be assembled in the imploded state to ignite varies roughly as P stag -2 , so among other requirements, there is a premium on reaching higher P stag to achieve ignition with the available laser energy. The U.S. inertial confinement fusion program (ICF) is pursuing higher P stag on NIF through improvements to capsule stability and symmetry. One can argue that recent experiments place an approximate upper bound on the ultimate ignition energy requirement. Scaling the implosions in spatial, temporal and energy scales shows that implosions of the demonstrated quality ignite robustly at 9-15 times the current energy of NIF. While lasers are unlikely to reach that bounding energy, it appears that pulsed power sources could plausibly do so, giving a range of paths forward for ICF depending on success in improving energy concentration. In this paper, I show the scaling arguments then discuss topics from my own involvement in HED fusion. The recent Viewfactor experiments at NIF have shed light on both the observed capsule drive deficit and errors in the detailed modelling of hohlraums. The latter could be an important factor in the inability to achieve the needed symmetry and energy concentration. The paper then recounts earlier work in Fast Ignition and the uses of pulsed power for HED and fusion applications. It concludes with a description of a method for improving pulsed power driven hohlraums that could potentially provide a factor of 10 in energy at NIF-like drive conditions and reach the energy bound for indirect drive ICF.

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Section: Pulsed Power Hohlraum-driven Fusionmentioning

confidence: 99%

Alternative Approaches to High Energy Density Fusion

Hammer¹

2016

Edward Teller Lectures

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“…5, the mainline z-pinch ICF targets are the double pinch target [34] and the dynamic hohlraum target [35]. Both targets are being developed for ICF with the goal of yields of ∼ 0.5 GJ.…”

Section: Targets For Z-pinch Ifementioning

confidence: 99%

Development Path for Z-Pinch IFE

Olson

Rochau

Slutz

et al. 2005

Fusion Science and Technology

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“…The double-ended vacuum hohlraum z-pinch-driven ICF concept [5] which has been extensively studied on the Z machine [6] relies on a cylindrical primary hohlraum which also serves as the return current canister for the z-pinch radiation source on axis. The surface area of the hohlraum is thus constrained by the initial geometry of the cylindrical wire array.…”

Section: Chapter 1 Introductionmentioning

confidence: 99%

Compact wire array sources: power scaling and implosion physics.

Serrano¹,

Chuvatin

Jones³

et al. 2008

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A series of ten shots were performed on the Saturn generator in short pulse mode in order to study planar and small-diameter cylindrical tungsten wire arrays at ∼5 MA current levels and 50-60 ns implosion times as candidates for compact z-pinch radiation sources. A new vacuum hohlraum configuration has been proposed in which multiple z pinches are driven in parallel by a pulsed power generator. Each pinch resides in a separate return current cage, serving also as a primary hohlraum. A collection of such radiation sources surround a compact secondary hohlraum, which may potentially provide an attractive Planckian radiation source or house an inertial confinement fusion fuel capsule. Prior to studying this concept experimentally or numerically, advanced compact wire array loads must be developed and their scaling behavior understood. The 2008 Saturn planar array experiments extend the data set presented in Ref.[1], which studied planar arrays at ∼3 MA, 100 ns in Saturn long pulse mode. Planar wire array power and yield scaling studies now include current levels directly applicable to multi-pinch experiments that could be performed on the 25 MA Z machine. A maximum total x-ray power of 15 TW (250 kJ in the main pulse, 330 kJ total yield) was observed with a 12-mm-wide planar array at 5.3 MA, 52 ns. The full data set indicates power scaling that is sub-quadratic with load current, while total and main pulse yields are closer to quadratic; these trends are similar to observations of compact cylindrical tungsten arrays on Z. We continue the investigation of energy coupling in these short pulse Saturn experiments using zero-dimensional-type implosion modeling and pinhole imaging, indicating 16 cm/μs implosion velocity in a 12-mm-wide array. The same phenomena of significant trailing mass and evidence for resistive heating are observed at 5 MA as at 3 MA. 17 kJ of Al K-shell radiation was obtained in one Al planar array fielded at 5.5 MA, 57 ns and we compare this to cylindrical array results in the context of a K-shell yield scaling model. We have also performed an initial study of compact 3 mm diameter cylindrical wire arrays, which are alternate candidates for a multi-pinch vacuum hohlraum concept. These massive 3.4 and 6 mg/cm loads may have been impacted by opacity, producing a maximum x-ray power of 7 TW at 4.5 MA, 45 ns. Future research directions in compact x-ray sources are discussed. 4 AcknowledgmentWe thank M. Lopez (1675), G. T. Liefeste (1675), and J. L. Porter (1670) for providing load hardware and diagnostic support; L.B. Nielsen-Weber (1675) and D.S. Nielsen (1675) for extensive support of diagnostic installation, fielding, and film processing;

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High yield inertial confinement fusion target design for a z-pinch-driven hohlraum

Cited by 144 publications

References 7 publications

Alternative Approaches to High Energy Density Fusion

Alternative Approaches to High Energy Density Fusion

Development Path for Z-Pinch IFE

Compact wire array sources: power scaling and implosion physics.

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