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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. Rev Sci Instrum 2023; 94:103501. [PMID: 37782217 DOI: 10.1063/5.0152680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Martinelli L, Mikitchuck D, Duval BP, Andrebe Y, Blanchard P, Février O, Gorno S, Elaian H, Linehan BL, Perek A, Stollberg C, Vincent B. Implementation of high-resolution spectroscopy for ion (and electron) temperature measurements of the divertor plasma in the Tokamak à configuration variable. Rev Sci Instrum 2022; 93:123505. [PMID: 36586937 DOI: 10.1063/5.0114538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
High resolution spectroscopy on the Tokamak à Configuration Variable (TCV) divertor plasma provided Doppler broadening measurements to infer the ion and neutral temperature of injected helium gas. This paper presents the Divertor Spectroscopy System's (DSS) access to He II ion temperature measurements over a broad range, ≈0.5-15 eV, with an uncertainty of <10% for most of the studied plasma discharges. TCV's shaping flexibility was employed to validate these measurements against Thomson scattering across the DSS lines of sight. In detachment-related experiments, Ti(He II) ≃ Te, making this diagnostic a reliable thermometer along the divertor leg plasma over the wide range of magnetic equilibria and divertor configurations achievable in TCV. A detailed description of the diagnostic hardware, data analysis, and sources of uncertainty is presented.
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Affiliation(s)
- L Martinelli
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - D Mikitchuck
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - B P Duval
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - Y Andrebe
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - P Blanchard
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - O Février
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - S Gorno
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - H Elaian
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - B L Linehan
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139, USA
| | - A Perek
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - C Stollberg
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
| | - B Vincent
- Swiss Plasma Center, École Polytechnique Fédérale de Lausanne (SPC-EPFL), CH-1015 Lausanne, Switzerland
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Février O, Reimerdes H, Theiler C, Brida D, Colandrea C, De Oliveira H, Duval B, Galassi D, Gorno S, Henderson S, Komm M, Labit B, Linehan B, Martinelli L, Perek A, Raj H, Sheikh U, Tsui C, Wensing M. Divertor closure effects on the TCV boundary plasma. Nuclear Materials and Energy 2021. [DOI: 10.1016/j.nme.2021.100977] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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De Oliveira H, Theiler C, Elaian H. A fast-reciprocating probe array for two-dimensional measurements in the divertor region of the Tokamak à configuration variable. Rev Sci Instrum 2021; 92:043547. [PMID: 34243470 DOI: 10.1063/5.0043523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 04/03/2021] [Indexed: 06/13/2023]
Abstract
A detailed description of the construction and commissioning of the fast-moving reciprocating divertor Langmuir probe array on the Tokamak à Configuration Variable (TCV) is presented. A horizontal array of 24 Langmuir probes (12 Mach probes) combined with a fast vertical movement provides unprecedented two-dimensional measurements of the plasma properties across the entire divertor outer leg volume and up to the X-point. The L-shape probe arm has to be very compact to minimize plasma perturbations and, at the same time, has to house 24 coaxial transmission lines, withstand time-averaged heat fluxes of up to ≈30 MW/m2 and accelerations of up to 8 g, and be resilient to violent plasma disruptions. For the fast vertical motion of the probe arm, extending up to 38 cm into the TCV vacuum vessel, an assembly with a precise and powerful linear electric motor (up to 4000 N of force) was mounted in a 4 m high structure within the limited space below the TCV. The diagnostic has already performed measurements in ≈200 plasma discharges and has been hit by ≈20 disruptions without suffering any critical damage. The measurements are qualitatively and quantitatively consistent with other reference diagnostics, such as upstream electron Thomson scattering and downstream wall-embedded Langmuir probes, and are used extensively on the TCV for experimental divertor studies and for comparisons with edge transport and turbulence code results.
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Affiliation(s)
- H De Oliveira
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - C Theiler
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - H Elaian
- Swiss Plasma Center (SPC), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Perek A, Linehan B, Wensing M, Verhaegh K, Classen I, Duval B, Février O, Reimerdes H, Theiler C, Wijkamp T, de Baar M. Measurement of the 2D emission profiles of hydrogen and impurity ions in the TCV divertor. Nuclear Materials and Energy 2021. [DOI: 10.1016/j.nme.2020.100858] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Wensing M, de Oliveira H, Loizu J, Colandrea C, Février O, Gorno S, Reimerdes H, Theiler C, Smolders A, Duval B, Tsui C, Wischmeier M, Brida D, Henderson S, Komm M. Experimental verification of X-point potential well formation in unfavorable magnetic field direction. Nuclear Materials and Energy 2020; 25:100839. [DOI: 10.1016/j.nme.2020.100839] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Rudischhauser L, Endler M, Höfel U, Hammond KC, Kallmeyer JP, Blackwell BD. The Langmuir probe system in the Wendelstein 7-X test divertor. Rev Sci Instrum 2020; 91:063505. [PMID: 32611053 DOI: 10.1063/1.5143013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 05/28/2020] [Indexed: 06/11/2023]
Abstract
The design and evaluation of the Langmuir probe system used in the first divertor operation phase of Wendelstein 7-X is described. The probes are integrated into the target plates and have individually facetted surfaces to keep the angle of incidence of the magnetic field within an appropriate range for different magnetic configurations. Multiple models for the derivation of plasma parameters from current-voltage characteristics are introduced. These are analyzed with regard to their assumptions and limitations, generalized, and adapted to our use case. A detailed comparison is made to determine the most suitable model. It is found that the choice of model has a large impact, for example, resulting in a change in the inferred temperatures of up to a factor two. This evaluation is implemented in a Bayesian modeling framework and automated to allow for joint analysis with other diagnostics and a replacement of ad hoc assumptions. We rigorously treat parameter uncertainties, revealing strong correlations between them. General and flexible model formulations permit an expansion to additional effects.
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Affiliation(s)
- L Rudischhauser
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - M Endler
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - U Höfel
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - K C Hammond
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - J P Kallmeyer
- Max-Planck-Institut für Plasmaphysik, 17491 Greifswald, Germany
| | - B D Blackwell
- Australian National University, Canberra, ACT 2600, Australia
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Perek A, Vijvers WAJ, Andrebe Y, Classen IGJ, Duval BP, Galperti C, Harrison JR, Linehan BL, Ravensbergen T, Verhaegh K, de Baar MR. MANTIS: A real-time quantitative multispectral imaging system for fusion plasmas. Rev Sci Instrum 2019; 90:123514. [PMID: 31893833 DOI: 10.1063/1.5115569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
This work presents a novel, real-time capable, 10-channel Multispectral Advanced Narrowband Tokamak Imaging System installed on the TCV tokamak, MANTIS. Software and hardware requirements are presented together with the complete system architecture. The image quality of the system is assessed with emphasis on effects resulting from the narrowband interference filters. Some filters are found to create internal reflection images that are correlated with the filters' reflection coefficient. This was measured for selected filters where significant absorption (up to 65% within ∼70 nm of the filter center) was measured. The majority of this was attributed to the filter's design, and several filters' performance is compared. Tailored real-time algorithms exploiting the system's capabilities are presented together with benchmarks comparing polling and event based synchronization. The real-time performance is demonstrated with a density ramp discharge performed on TCV. The behavior of spectral lines' emission from different plasma species and their interpretation are qualitatively described.
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Affiliation(s)
- A Perek
- Dutch Institute for Fundamental Energy Research (DIFFER), De Zaale 20, 5612 AJ Eindhoven, The Netherlands
| | - W A J Vijvers
- Dutch Institute for Fundamental Energy Research (DIFFER), De Zaale 20, 5612 AJ Eindhoven, The Netherlands
| | - Y Andrebe
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - I G J Classen
- Dutch Institute for Fundamental Energy Research (DIFFER), De Zaale 20, 5612 AJ Eindhoven, The Netherlands
| | - B P Duval
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - C Galperti
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - J R Harrison
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - B L Linehan
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NW17, Cambridge, Massachusetts 02139, USA
| | - T Ravensbergen
- Dutch Institute for Fundamental Energy Research (DIFFER), De Zaale 20, 5612 AJ Eindhoven, The Netherlands
| | - K Verhaegh
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - M R de Baar
- Dutch Institute for Fundamental Energy Research (DIFFER), De Zaale 20, 5612 AJ Eindhoven, The Netherlands
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De Oliveira H, Marmillod P, Theiler C, Chavan R, Février O, Labit B, Lavanchy P, Marlétaz B, Pitts RA. Langmuir probe electronics upgrade on the tokamak à configuration variable. Rev Sci Instrum 2019; 90:083502. [PMID: 31472647 DOI: 10.1063/1.5108876] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
A detailed description of the Langmuir probe electronics upgrade for TCV (Tokamak à Configuration Variable) is presented. The number of amplifiers and corresponding electronics has been increased from 48 to 120 in order to simultaneously connect all of the 114 Langmuir probes currently mounted in the TCV divertor and main-wall tiles. Another set of 108 amplifiers is ready to be installed in order to connect 80 new probes, built in the frame of the TCV divertor upgrade. Technical details of the amplifier circuitry are discussed as well as improvements over the first generation of amplifiers developed at SPC (formerly CRPP) in 1993/1994 and over the second generation developed in 2012/2013. While the new amplifiers have been operated successfully for over a year, it was found that their silicon power transistors can be damaged during some off-normal plasma events. Possible solutions are discussed.
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Affiliation(s)
- H De Oliveira
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Marmillod
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - C Theiler
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - R Chavan
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Février
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - B Labit
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - P Lavanchy
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - B Marlétaz
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - R A Pitts
- ITER Organization, Route de Vinon sur Verdon, CS90 046, 13067 St Paul Lez Durance, Cedex, France
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Nespoli F, Bufferand H, Valentinuzzi M, Fedorczak N, Ciraolo G, Serre E, Marandet Y, Maurizio R, De Oliveira H, Labit B, Komm M, Faitsch M, Elmore S. Application of a two-fluid two-point model to SolEdge2D-EIRENE simulations of TCV H-mode plasma. Nuclear Materials and Energy 2019. [DOI: 10.1016/j.nme.2018.11.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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