Self-Regulated Plasma Heat Flux Mitigation Due to Liquid Sn Vapor Shielding

Eden, van Gg Stein; Morgan, T.W.; Aussems, D.U.B.; Berg, van den Ma; Bystrov, K.; Sanden, van de Mcm Richard

doi:10.1103/physrevlett.116.135002

Cited by 64 publications

(62 citation statements)

References 24 publications

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“…It is expected that vapor shielding phenomena will play an important role in power handling at high input powers. Earlier studies of this phenomenon have been performed for solid targets [14,15], and for liquid tin [6]. It was found that when increasing the applied power density to the target a point is encountered beyond which the surface temperature is very insensitive to the applied power: a locking temperature.…”

Section: In Figmentioning

confidence: 99%

Power handling and vapor shielding of pre-filled lithium divertor targets in Magnum-PSI

et al. 2019

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To develop realistic liquid lithium divertors for future fusion reactors, this paper aims to improve understanding of its power handling capabilities. A liquid lithium divertor target prototype, designed to facilitate liquid metal experiments in tokamaks, was tested in Magnum-PSI. The target has an internal reservoir pre-filled with lithium and aims to passively re-supply the textured plasma facing surface during operation. To assess the power handling capability the target was exposed to helium plasmas with increasing power flux density in the linear plasma device Magnum-PSI. Temperature response of the lithium targets was recorded via IR camera, and compared to FEM modeling taking into account dissipation via Li in the plasma. It was found that the target works as intended and can take up to 9±1 MW/m 2 for 10 seconds before the mesh layer is damaged, and could continue operating at higher power densities even after being damaged. The total lifetime of the targets was up to 100 seconds. Overall the targets are found suitable for use in tokamak experiments. Additionally, a central surface temperature evolution indicative of vapor shielding was observed on intact targets. Predicting the target temperature (and consequently the evaporation rates and thermal stresses) is considered very relevant for the design of lithium divertor targets for DEMO. The observed temperature response could indeed be replicated through modeling, which showed that a significant power fraction was dissipated by the lithium in the plasma.

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Section: In Figmentioning

confidence: 99%

Power handling and vapor shielding of pre-filled lithium divertor targets in Magnum-PSI

et al. 2019

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“…Relevant liquid metal properties include viscosities, diffusivities, hydrogen solubilities, and wetting properties. Recently, experimental studies have been performed focusing on the understanding of properties of liquid lithium 9,10 and liquid tin 11,12 in the context of plasma-facing materials.…”

Section: Introductionmentioning

confidence: 99%

Structural and dynamic properties of liquid tin from a new modified embedded-atom method force field

et al. 2017

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A new modified embedded-atom method (MEAM) force field is developed for liquid tin. Starting from the Ravelo and Baskes force field [Phys. Rev. Lett. 79, 2482], the parameters are adjusted using a simulated annealing optimization procedure in order to obtain better agreement with liquid-phase data. The predictive capabilities of the new model and the Ravelo and Baskes force field are evaluated using molecular dynamics by comparing to a wide range of first-principles and experimental data. The quantities studied include crystal properties (cohesive energy, bulk modulus, equilibrium density, and lattice constant of various crystal structures), melting temperature, liquid structure, liquid density, self-diffusivity, viscosity, and vapor-liquid surface tension.It is shown that although the Ravelo and Baskes force field generally gives better agreement with the properties related to the solid phases of tin, the new MEAM force field gives better agreement with liquid tin properties.

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“…1,2 This particular work is motivated by the plasma-liquid interactions inherent in magnetic confinement fusion devices, such as tokamaks, either due to melt damage of the metal walls 3 or in new liquid metal divertor concepts. [4][5][6] The ejection of molten droplets has been observed in both cases 7,8 and is of considerable concern to the operation of a successful fusion device. Understanding the stability of the liquid metal surface is a critical issue.…”

mentioning

confidence: 99%

“…The perturbation to the electric potential is then compared to the boundary condition / 1;z¼0 ¼ E z0;z¼0 n 1 , and the initial guessed values are updated accordingly. This cycle of shooting and correcting is continued until the / 1 boundary condition is satisfied to within a given error tolerance which was taken to be at least 1 part in 10 5 . The codes used to generate and analyse these results are available at http://www.github.com/joshholgate/ELIPS.…”

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confidence: 99%

Electrohydrodynamic stability of a plasma-liquid interface

Holgate

Coppins

Allen

2018

Applied Physics Letters

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Many plasma applications involve the plasma coming into contact with a liquid surface. Previous analyses of the stability of such liquid surfaces have neglected the presence of the sheath region between the bulk plasma and the liquid. Large electric fields, typically in excess of several MV m−1, and strong ion flows are present in this region. This paper considers a linear perturbation analysis of a liquid-sheath interface in order to find the marginal condition for instability. This condition shows that molten metal surfaces in tokamak edge plasmas are stable against the electric field, if a normal sheath is formed, due to the impact of ions on the surface. The stabilization of the liquid surface by ion bombardment is encouraging for the ongoing development of plasma-liquid technologies.

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Self-Regulated Plasma Heat Flux Mitigation Due to Liquid Sn Vapor Shielding

Cited by 64 publications

References 24 publications

Power handling and vapor shielding of pre-filled lithium divertor targets in Magnum-PSI

Power handling and vapor shielding of pre-filled lithium divertor targets in Magnum-PSI

Structural and dynamic properties of liquid tin from a new modified embedded-atom method force field

Electrohydrodynamic stability of a plasma-liquid interface

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