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Pandey A, Bohm S, Carls A, Cordes C, Endler M, Fellinger J, Freundt S, Gallowski K, Hammond K, Hathiramani D, Isberner G, Kallmeyer JP, Krause M, Kügler J, Otte M, Pedersen TS, Rondeshagen D, Ruhnau J, Schröder T, Sieber T, Wendorf J. Pop-up Langmuir probe diagnostic in the water cooled divertor of Wendelstein 7-X. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:043503. [PMID: 38563720 DOI: 10.1063/5.0188738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 03/14/2024] [Indexed: 04/04/2024]
Abstract
The design, development, and successful implementation of pop-up Langmuir probes installed in the water-cooled divertor of W7-X are described. The probes are controlled by drive coils (actuators) installed behind the divertor plates. These drive coils make use of the magnetic field in W7-X to move the probe tips into and out of the plasma. The drive coils were installed in the vacuum vessel after extensively testing the durability of the coils and analyzing the criteria for safe operation. The probe design is carefully tailored for each of the 36 probe tips in order to be suitable for the different magnetic field configurations used in W7-X and ensure that the probes do not present leading edges to the magnetic flux tubes. An electronic bridge circuit is used for measurement to compensate for the effects of signal propagation time on the long cable lengths used. The diagnostic is integrated with the segment control of W7-X for automated operation and control of the diagnostic. The evaluation of the results from the plasma operation is presented after accounting for appropriate sheath expansion for negative bias voltage on the probes.
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Affiliation(s)
- A Pandey
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - S Bohm
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - A Carls
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - C Cordes
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - M Endler
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - J Fellinger
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - S Freundt
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - K Gallowski
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - K Hammond
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D Hathiramani
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - G Isberner
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - J P Kallmeyer
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - M Krause
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - J Kügler
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - M Otte
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | | | - D Rondeshagen
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - J Ruhnau
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - T Schröder
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - T Sieber
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
| | - J Wendorf
- Max-Planck Institut für Plasmaphysik, Greifswald 17491, Germany
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Ryan PJ, Elmore SD, Harrison JR, Lovell J, Stephen R. Overview of the Langmuir probe system on the Mega Ampere Spherical Tokamak (MAST) Upgrade. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:103501. [PMID: 37782217 DOI: 10.1063/5.0152680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 09/08/2023] [Indexed: 10/03/2023]
Abstract
A detailed description of the Langmuir probe system on Mega Ampere Spherical Tokamak Upgrade is presented. The system features 850 tile-embedded probes and 40 bespoke electronic modules that each have the capability to drive and acquire data from up to 16 probes in a time-multiplexed manner. The system provides spatiotemporal-resolved measurements (1 cm and ∼1 ms, respectively) in the divertor region of ion saturation current, electron temperature, and floating potential. The standard interpretation of current-voltage (IV) characteristics is to apply a four-parameter fit, based on unmagnetized probe theory, which includes a linear model for the ion saturation region. To mitigate the effect of the magnetic field, analysis is restricted to the region of the IV characteristic, which is sensitive to only the tail of the electron energy distribution function.
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Affiliation(s)
- P J Ryan
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - S D Elmore
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J R Harrison
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J Lovell
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - R Stephen
- United Kingdom Atomic Energy Authority, Culham Centre for Fusion Energy, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
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Mayer M, Kandler M, Dhard C, Elgeti S, Gao Y, Jakubowski M, Naujoks D, Rudischhauser L. Assessment of carbon net erosion/deposition at the divertor of W7-X. NUCLEAR MATERIALS AND ENERGY 2022. [DOI: 10.1016/j.nme.2022.101352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Wang E, König R, Krychowiak M, Brezinsek S, Drews P, Gradic D, Jakubowski M, Kornejew P, Kremeyer T, Killer C, Liang Y, Neubauer O, Pandey A, Rudischhauser L, Sereda S, Schlisio G, Xu S. Radiation characteristics of detached divertor plasmas in W7-X. NUCLEAR MATERIALS AND ENERGY 2022. [DOI: 10.1016/j.nme.2022.101283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Endler M, Baldzuhn J, Beidler C, Bosch HS, Bozhenkov S, Buttenschön B, Dinklage A, Fellinger J, Feng Y, Fuchert G, Gao Y, Geiger J, Grulke O, Hartmann D, Jakubowski M, König R, Laqua H, Lazerson S, McNeely P, Naujoks D, Neuner U, Otte M, Pasch E, Sunn Pedersen T, Perseo V, Puig Sitjes A, Rahbarnia K, Rust N, Schmitz O, Spring A, Stange T, von Stechow A, Turkin Y, Wang E, Wolf R. Wendelstein 7-X on the path to long-pulse high-performance operation. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112381] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hubeny M, Höschen D, Neubauer O, Hoek R, Czymek G, Naujoks D, Hathiramani D, Bardawil D, Unterberg B, König R, Brezinsek S, Linsmeier C. Progress on MATEO probe heads and observation system. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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