The flush-mounted rail Langmuir probe array designed for the Alcator C-Mod vertical target plate divertor

Kuang, A. Q.; Brunner, D.; LaBombard, B.; Leccacorvi, R.; Vieira, R.

doi:10.1063/1.5023905

Title: The flush-mounted rail Langmuir probe array designed for the Alcator C-Mod vertical target plate divertor

Journal Article · Thu Apr 26 00:00:00 EDT 2018 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.5023905· OSTI ID:1527102

^[1]; Brunner, D. ^[1]; LaBombard, B. ^[1]; Leccacorvi, R. ^[1]; Vieira, R. ^[1]

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

An array of flush-mounted and toroidally elongated Langmuir probes (henceforth called rail probes) have been specifically designed for the Alcator C-Mod’s vertical target plate divertor and operated over multiple campaigns. The “flush” geometry enables the tungsten electrodes to survive high heat flux conditions in which traditional “proud” tungsten electrodes suffer damage from melting. The toroidally elongated rail-like geometry reduces the influence of sheath expansion, which is an important effect to consider in the design and interpretation of flush-mounted Langmuir probes. The new rail probes successfully operated during C-Mod’s FY2015 and FY2016 experimental campaigns with no evidence of damage, despite being regularly subjected to heat flux densities parallel to the magnetic field exceeding ~1 GW m^-2 for short periods of time. A comparison between rail and proud probe data indicates that sheath expansion effects were successfully mitigated by the rail design, extending the use of these Langmuir probes to incident magnetic field line angles as low as 0.5°.

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Research Organization:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Organization:: USDOE Office of Science (SC)

Grant/Contract Number:: SC0014264; FC02-99ER54512

OSTI ID:: 1527102

Alternate ID(s):: OSTI ID: 1434828

Journal Information:: Review of Scientific Instruments, Vol. 89, Issue 4; ISSN 0034-6748

Publisher:: American Institute of Physics (AIP)Copyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 10 works

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High-resolution heat flux width measurements at reactor-level magnetic fields and observation of a unified width scaling across confinement regimes in the Alcator C-Mod tokamak Brunner, D.; LaBombard, B.; Kuang, A. Q. Nuclear Fusion, Vol. 58, Issue 9 https://doi.org/10.1088/1741-4326/aad0d6	journal	July 2018
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