An Overview of the Hybrid Illinois Device for Research and Applications Material Analysis Test-stand (HIDRA-MAT)

Shone, Andrew; Koyn, Zachariah; Rizkallah, Rabel; O’Dea, D.; Kapat, Aveek; Golba, G.; Hoffman, Jacob B.; Kurukulasuriya, D.; Tang, Qiang; Castro, Alfonso; Allain, Jean Paul; Andruczyk, Daniel

doi:10.1007/s10894-020-00260-7

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…Recent experiments at the University of Illinois Urbana-Champaign (UIUC) reported unexpected observations of low-recycling regimes in helium stellarator plasmas induced by in-operando lithium evaporations [20]. Experiments were conducted in the Hybrid Illinois Device for Research and Applications (HIDRA) and lithium evaporations were done utilizing the HIDRA-Material Analysis Test-stand (HIDRA-MAT) [21][22][23]. When lithium was evaporated into the helium plasma, neutral pressure decreased by an order of magnitude, and helium spectral lines also decreased despite constant electron cyclotron resonance heating (ECRH) and helium ow rate into HIDRA.…”

Section: Motivationmentioning

confidence: 99%

In-operando Lithium Evaporation Inducing Helium Retention in Long-Pulse HIDRA Helium Plasmas

Shone,

Rizkallah,

O’Dea

et al. 2023

J Fusion Energ

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The Lithium Evaporation EXperiment (LEEX) investigated helium retention effects induced by in-operando lithium evaporations into the Hybrid Illinois Device for Research and Applications (HIDRA) at the University of Illinois Urbana-Champaign (UIUC). Lithium droplets were applied to tungsten samples and then exposed to a 600s helium plasma at different distances from the plasma edge (D=0mm, D=25mm, D=47.5mm). Spectrometers, residual gas analyzers (RGAs), and pressure gauges were employed to characterize the plasma throughout the plasma discharge. LEEX data has con rmed previous results at UIUC of in-operando lithium evaporations producing a low-recycling regime for HIDRA helium plasmas and additionally proves the retained specie is helium. The lithium evaporation from the D=25mm case had an 85.3% ± 1% increase in helium retention in the low recycling regime when compared to the steady state plasma of the LEEX control shot. Data presented substantiates previous helium retention claims and advances research surrounding liquid metal PFCs. A retention mechanism has not been identi ed, but further research utilizing HIDRA and HIDRA-MAT aims to investigate this. This study's outcomes are thoroughly presented and provide an additional justi cation for conducting further research on lithium's behavior in fusion environments, given its substantial potential impact on the development of plasmafacing components (PFCs).

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Section: Motivationmentioning

confidence: 99%

In-operando Lithium Evaporation Inducing Helium Retention in Long-Pulse HIDRA Helium Plasmas

Shone,

Rizkallah,

O’Dea

et al. 2023

J Fusion Energ

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“…These experiments were not directly associated with the LMPFC program, but have direct consequences for the program. Liquid lithium was introduced into the plasma using the material analysis test stand 38 and a lithium injector. 39 The aim of the experiments was to test porous tungsten samples in helium plasma without and with lithium.…”

Section: Note On Helium Retentionmentioning

confidence: 99%

Overview of Liquid-Metal PFC R&D at the University of Illinois Urbana-Champaign

Andruczyk

Rizkallah

O’Dea

et al. 2023

Fusion Science and Technology

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The design and implementation of future flowing liquid-lithium plasma-facing components (LLPFCs) will be dependent on several factors. Of course, one of the most important is the need to be able to deal with high heat fluxes incident on the surface of the LLPFCs, but there are also several other important liquid-metal behaviors that have been identified for their critical impact on the feasibility of a LLPFC. One of these is the ability to constantly wet 100% of the plasma-facing component area and the best way to achieve that. Another key point is knowing and understanding the erosion and corrosion of the surfaces subject to a flowing liquid-lithium system and the ability for hydrogen and helium uptake by the system.The Center for Plasma Material Interactions (CPMI) has been tasked with looking at these various issues. The Mock-up Entry module for EAST device was used to investigate wetting and erosion effects and to design a suitable distribution and collection system with a liquid-lithium loop. The vapor shielding effects of lithium on the surface were also modeled and studied. A model coupling CRANE, an open-source global reaction network solver, and Zapdos, a plasma transport solver, is being developed to better understand the dynamics of the vapor cloud. Experiments on the Magnum-PSI at the Dutch Institute for Fundamental Energy Research have been carried out to study the vapor shielding effect and obtain experimental benchmarks to verify the model. Also, initial experiments using the Hybrid Illinois Device for Research and Applications have been performed to understand the pumping effects of lithium on helium.Experiments with a drop of liquid lithium (~100 mg) into a helium plasma have shown the ability of lithium to take out the cold recycling helium gas as well as hydrogen and oxygen impurity gases. The improvement in plasma performance was significant, and further understanding of this effect will have impacts on how future LLPFCs will be designed. Further investigation into the exact mechanism for helium pumping by lithium needs to be performed in the future. This paper presents a summary of the results obtained at the CPMI.

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“…The HIDRA-MAT was developed to utilize the long pulse capabilities of HIDRA and is described by Shone et al [27]. The concept is similar to that of the MAPP used on LTX and NSTX [39] in that it provides an in-vacuo method to expose samples to the plasma and then do analysis on them without breaking vacuum and thus contaminating any surface effects.…”

Section: Materials Analysis Test Stand (Hidra-mat)mentioning

confidence: 99%

“…The concept is similar to that of the MAPP used on LTX and NSTX [39] in that it provides an in-vacuo method to expose samples to the plasma and then do analysis on them without breaking vacuum and thus contaminating any surface effects. Detailed description of HIDRA-MAT can be found in Shone et al [27] but one of the main features of HIDRA-MAT is that the sample surface can be rotated 180 • , allowing a lithium injector to apply a drop of liquid lithium [40] onto a surface on the probe head in-vacuo. The probe head can be heated to ensure wetting of the surface.…”

Section: Materials Analysis Test Stand (Hidra-mat)mentioning

confidence: 99%

“…The aim was to expose the W-Li surface to the HIDRA steady state plasma edge, in the process evaporate and ionize lithium within the HIDRA plasma column and measure hydrogen and possibly helium retention by lithium atoms in the solid phase. This was done using the newly commissioned HIDRA-Material Analysis Test-stand (MAT) [27]. This paper will discuss the results of a helium plasma exposure and possible implications to PFC and divertor design in future plasma-burning fusion devices.…”

Section: Introductionmentioning

confidence: 99%

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First lithium experiments in HIDRA and evidence of helium retention during quasi-steady-state stellarator plasma operations

Andruczyk

Koyn

Allain

et al. 2022

Plasma Phys. Control. Fusion

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Experiments in HIDRA have had operational discharges between tdischarge = 60 – 1000 s using ECRH heating. This means that quasi-steady-state plasma discharges reach conditions to study long-pulse plasma material interactions. The HIDRA-MAT PMI diagnostic is used to place a drop of lithium onto a heated tungsten surface, transfer the sample in-vacuo and expose it in a helium plasma. Helium is of interest as there is an open question to whether lithium will be able to remove helium ash in real fusion devices. It was also observed that the plasma density and temperature increased by over 2.5 times. During lithium evaporation, as significant lithium ionization occurs, there is a 91% drop in the neutral pressure that is injected into the vessel, despite a constant flow of He gas. This is backed up by the fact that the helium neutral light intensity also drops. At one point in the discharge a lithium plasma is created, as indicated by an increase in Li+ emission and a complete reduction in He+ emission, but the electron density jumps from ne = 3×1018 m-3 to over ne = 8×1018 m-3 while the core temperature stays relatively constant between Te = 16 eV – 20 eV. Once the source of lithium is expired, residual Li and Li+ in the plasma maintain a low neutral He background which allows a He plasma to re-establish and be more efficiently heated. Here the density drops down to ne = 2×1018 m-3 and the electron temperature increases from Te = 20 eV to over Te = 50 eV. This is also indicated by the He+ emission re-establishing and having a higher intensity. In this paper we show the results from the first lithium campaign in HIDRA. In the presence of lithium, the helium disappears from the plasma via an as of yet unknown complex relationship that needs to be further studied.

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An Overview of the Hybrid Illinois Device for Research and Applications Material Analysis Test-stand (HIDRA-MAT)

Cited by 7 publications

References 18 publications

In-operando Lithium Evaporation Inducing Helium Retention in Long-Pulse HIDRA Helium Plasmas

In-operando Lithium Evaporation Inducing Helium Retention in Long-Pulse HIDRA Helium Plasmas

Overview of Liquid-Metal PFC R&D at the University of Illinois Urbana-Champaign

First lithium experiments in HIDRA and evidence of helium retention during quasi-steady-state stellarator plasma operations

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