The effects of insulating coatings and current prepulse on tungsten planar wire array Z-pinches

Li, M.; Sheng, Liang; Wang, L. P.; Li, Yan Hui; Chen, Zhao; Yuan, Y.; Zhang, X. J.; Zhang, M.; Bodong, Peng; Zhang, J. H.; Zhang, S. G.; Qiu, Mengtong; Li, X. W.

doi:10.1063/1.4938276

Cited by 11 publications

(3 citation statements)

References 15 publications

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“…MHD numerical simulations of polyimide-coated tungsten wires interacting with high pulsed currents demonstrated that the coating reduces the coronal plasma generation [33,34]. Furthermore, in studies with magnetically accelerated imploding metallic liners -the MagLIF concept -the use of dielectric coatings has recently succeeded in stabilizing and enhancing the implosion phenomena [23,24], while the effects of insulating coatings on tungsten planar wire array Z-pinches [36,37] have demonstrated that the expansion velocity increases, and that the ablation process as well as the precursor plasma are suppressed. Nevertheless, the aforementioned studies do not focus on the influence of the ETM phase of the target's heating as the experimental measurements and the corresponding simulations initiate the study from the plasma phase.…”

Section: Introductionmentioning

confidence: 99%

Instability growth mitigation study of a dielectric coated metallic wire in a low current Z-pinch configuration

Kaselouris

Tamiolakis

Fitilis

et al. 2021

Plasma Phys. Control. Fusion

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An experimental and numerical study of the nanosecond electrical explosion dynamics of bare and dielectric coated metallic wires in vacuum is reported. A table top Z-pinch generator down-tuned to generate a peak current of 40 kA with a rise time of 60 ns is implemented for the experiments in the skin effect mode. Optical probing diagnostics as well as multiphysics-multiphase simulations are used to study the spatiotemporal dynamics of the exploded wire from the solid to the plasma phase. The results show that the inclusion of the dielectric coating mitigates the electro-thermo-mechanical instability growth developed prior to plasma formation, which results in a subsequent reduced magnetohydrodynamic instability growth in the plasma phase. The study offers valuable insights into the understanding of the seeding mechanisms for the generation of plasma instabilities and the efforts for their growth rate suppression.

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Section: Introductionmentioning

confidence: 99%

Instability growth mitigation study of a dielectric coated metallic wire in a low current Z-pinch configuration

Kaselouris

Tamiolakis

Fitilis

et al. 2021

Plasma Phys. Control. Fusion

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show abstract

“…The inherent prepulse current in some Z-pinch facilities, which is a small amplitude current pulse with a duration of several hundreds of nanoseconds before the rising of the main current [12][13][14]. It is thought that the slow-rising prepulse should be suppressed because it can lead to the early formation of the corona plasma that would terminate the Joule heating of the wires.…”

Section: Introductionmentioning

confidence: 99%

“…Calamy et al used an independent LC circuit to produce a microsecond current prepulse to preheat the aluminum wires in the Z-pinch experiment, and an improvement in the axial homogeneity of implosion was observed [15]. Furthermore, Li et al investigated the effect of a current prepulse of 70 kA 100 ns −1 on the implosion of planar tungsten wire arrays, and a shorter x-ray pulse was obtained [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of the prepulse current with an adjustable time-delay on the implosion dynamics of two-wire Z-pinch

Zhang

et al. 2020

Plasma Phys. Control. Fusion

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Experiments are performed on the 'Qin-1' double pulse current generator at Xi'an Jiaotong University to study the effect of the prepulse current on the implosion dynamics of two-wire Z-pinches. An independent prepulse current with an adjustable time-delay (T delay ) is introduced to preheat the wires before the start of the main pulse current. An estimation of the deposited energy and the areal density reconstructed from the interferogram suggest that the wires are partly vaporized with a gasification fraction of ∼67%. The prepulse preconditioning has a redistribution effect on the load mass, which determines the subsequent implosion process. The planar implosion of the two-wire load with a preset T delay ⩽ 450 ns can be divided into the two-layer phase and the merged implosion phase. The snowplow-like implosion is the main characteristic of the shot with a 1050 ns T delay . The ablation streams gradually disappear with the increasing T delay . The proportion of the mass that participates in implosion is increased as the preset T delay increases from 120 ns to 1050 ns.

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Observation of fast expansion velocity with insulating tungsten wires on ∼80 kA facility

Zhang

et al. 2016

Physics of Plasmas

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This paper presents experimental results on the effects of insulating coatings on tungsten planar wire array Z-pinches on an 80 kA, 100 ns current facility. Expansion velocity is obviously increased from ∼0.25 km/s to ∼3.5 km/s by using the insulating coatings. It can be inferred that the wire cores are in gaseous state with this fast expansion velocity. An optical framing camera and laser probing images show that the standard wire arrays have typical ablation process which is similar to their behaviors on mega-ampere facilities. The ablation process and precursor plasma are suppressed for dielectric tungsten wires. The wire array implosion might be improved if these phenomena can be reproduced on Mega-ampere facilities.

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The effects of insulating coatings and current prepulse on tungsten planar wire array Z-pinches

Cited by 11 publications

References 15 publications

Instability growth mitigation study of a dielectric coated metallic wire in a low current Z-pinch configuration

Instability growth mitigation study of a dielectric coated metallic wire in a low current Z-pinch configuration

Effect of the prepulse current with an adjustable time-delay on the implosion dynamics of two-wire Z-pinch

Observation of fast expansion velocity with insulating tungsten wires on ∼80 kA facility

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