Overview of the Dynamic Hohlraum X-Ray Source at Sandia National Laboratories

Sanford, T. W. L.

doi:10.1109/tps.2007.914165

Cited by 14 publications

(7 citation statements)

References 45 publications

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“…[1][2][3][4][5] However, to achieve the Z-pinch-driven ICF, in addition to the demand of higher drive currents, say up to 60 MA, 6 there are some physical problems involved in the x-ray radiation source needed to be further studied, such as the extent of the flexibility of waveform of the x-ray power to be possibly modified for isentropic compression of D-T capsule; the effects of the precursor plasma, which results from wire-array ablation and fills interior of the array, on the following implosion after the end of wire-array ablation; as well as on the D-T capsule under the concept of the dynamic hohlraum. 4,7 To solve these problems requires us to experimentally and theoretically understand the formation and the characteristics of the precursor plasma and its effects on the implosion performance of the wire-array Z-pinch.…”

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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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: 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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“…For the same prepulse current, one cannot increase indefinitely the wire number to achieve better azimuthal symmetry without degradation of the axial symmetry, due to decreasing of the current rate per wire [3,5,19]. Also, smaller-diameter wires, typically employed in larger-wire-number arrays, produce stronger radial electric fields that would require higher current rates per wire to minimize polarity-effect induced axial inhomogeneity.…”

Section: Discussionmentioning

confidence: 99%

“…Symmetrical ablation must be maintained for any parameter-scan experiments in order to best observe expected scaling relationships [18]. Experiments designed to maximize x-ray power by varying load parameters as suggested by MHD simulations have failed to demonstrate the predicted behavior [19] probably because the symmetry conditions assumed in the simulations were violated when the optimum wire-initiation requirements were no longer met.…”

Section: Discussionmentioning

confidence: 99%

New paradigm : controlling initiation phase is necessary for optimization of wire-array z-pinch performance.

Rosenthal¹,

Sarkisov

Sanford³

2008

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The initiation phase of a wire-array is of paramount importance for achieving an axially homogeneous z-pinch and reproducible, high x-ray power. The significance of wire-array initiation during current prepulse for z-pinch performance has not been widely acknowledged. To achieve new levels of progress in wire-array z-pinch physics it is necessary to accept the importance of initiation physics, and to implement diagnostics of array initiation. This communication provides a brief review pointing out the need to control the initiation phase of a wire array for optimum z-pinch performance, and suggesting why multi-MA wire-array z-pinch experiments fail to meet MHD expectations.

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“…[16]). Thephotospheres of DAsdonot require such extremeconditions.Byplacing our gascell ∼ 35 cm away from thecentral experiment,t he X-ray fluxr adially diffuses to ad ensity suitablefor our purposes (see Sanford [17]for adescriptionofthe radiationenvironment).Itshouldbenoted that ours is not theo nlya strophysicse xperiment making useo fa nX -ray beam line. Hall et al [18] are investigatingt he atomic-kinetic andr adiative characteristicso fp hotoionized plasmasrelevanttosuchenvironments as activegalactic nucleiand X-ray binaries.All theseexperiments − Baileyetal.…”

Section: Experimental Plat Formmentioning

confidence: 99%