Search

Your search keyword '"Nicolas Fedorczak"' showing total 2 results
Start Over Author "Nicolas Fedorczak" Journal physica scripta
2 results on '"Nicolas Fedorczak"'

1. Sustained W-melting experiments on actively cooled ITER-like plasma facing unit in WEST

Author

Panagiotis Tolias, M. Richou, L. Dubus, V. Bruno, Eric Nardon, E. Delmas, Fabrice Rigollet, Lena Delpech, K. Krieger, Patrick Maget, X. Regal-Mezin, J. W. Coenen, P. Mandelbaum, C. Desgranges, T. Loarer, J-L Schwob, Clarisse Bourdelle, Marc Missirlian, C. Pocheau, E. Tsitrone, C. Reux, R. Mitteau, A. Durif, J. L. Gardarein, A. Ekedahl, Jonathan Gaspar, A. Grosjean, A. Podolnik, E. Thoren, Nicolas Fedorczak, S. Brezinsek, X. Courtois, R. Dejarnac, Svetlana V. Ratynskaia, J. Gerardin, C. Guillemaut, M. Firdaouss, Yann Corre, N. Chanet, M. Diez, O. Skalli-Fettachi, Rémy Nouailletas, M. Houry, P. Moreau, J. P. Gunn, P Reilhac, WEST Team, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Royal Institute of Technology [Stockholm] (KTH ), Institut fur Energie und Klimaforschung - Plasmaphysik (IEK-4), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, University of Wisconsin-Madison, Czech Academy of Sciences [Prague] (CAS), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Azrieli College of Engineering, Jerusalem, Israel, The Hebrew University of Jerusalem (HUJ), European Project: 633053,H2020,EURATOM-Adhoc-2014-20,EUROfusion(2014), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Department of Space and Plasma Physics [Stockholm], KTH School of Electrical Engineering, Royal Institute of Technology [Stockholm] (KTH )-Royal Institute of Technology [Stockholm] (KTH ), Helmholtz-Gemeinschaft = Helmholtz Association, Institute of Plasma Physics [Praha], Rigollet, Fabrice, and Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium - EUROfusion - - H20202014-01-01 - 2018-12-31 - 633053 - VALID

Subjects
[PHYS]Physics [physics], Materials science, [SPI] Engineering Sciences [physics], Nuclear engineering, Heat flux calculation, Plasma, Condensed Matter Physics, 01 natural sciences, IR thermography, Atomic and Molecular Physics, and Optics, 010305 fluids & plasmas, Unit (housing), [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], Plasma Facing Unit, [SPI]Engineering Sciences [physics], [PHYS.MECA.MEMA] Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], Tungsten melting, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], 010306 general physics, Mathematical Physics, [SPI.MECA.THER] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph]
Abstract

The consequences of tungsten (W) melting on divertor lifetime and plasma operation are high priority issues for ITER. Sustained and controlled W-melting experiment has been achieved for the first time in WEST on a poloidal sharp leading edge of an actively cooled ITER-like plasma facing unit (PFU). A series of dedicated high power steady state plasma discharges were performed to reach the melting point of tungsten. The leading edge was exposed to a parallel heat flux of about 100 MW.m−2 for up to 5 s providing a melt phase of about 2 s without noticeable impact of melting on plasma operation (radiated power and tungsten impurity content remained stable at constant input power) and no melt ejection were observed. The surface temperature of the MB was monitored by a high spatial resolution (0.1 mm/pixel) infrared camera viewing the melt zone from the top of the machine. The melting discharge was repeated three times resulting in about 6 s accumulated melting duration leading to material displacement from three similar pools. Cumulated on the overall sustained melting periods, this leads to excavation depth of about 230 μm followed by a re-solidified tungsten bump of 200 μm in the JxB direction.

Published
2021
Full Text
View/download PDF

2. Infra-red thermography estimate of deposited heat load dynamics on the lower tungsten divertor of WEST

Author

T. Loarer, R. Dejarnac, Jonathan Gaspar, S. Brezinsek, M. Firdaouss, Jérôme Bucalossi, A. Grosjean, V. Moncada, Nicolas Fedorczak, E. Tsitrone, Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut universitaire des systèmes thermiques industriels (IUSTI), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institute of Plasma Physics [Praha], Czech Academy of Sciences [Prague] (CAS), Institut fur Energie und Klimaforschung - Plasmaphysik (IEK-4), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Tokamak, Materials science, Toroid, Divertor, Plasma, Condensed Matter Physics, 01 natural sciences, Temperature measurement, Atomic and Molecular Physics, and Optics, Magnetic flux, 010305 fluids & plasmas, law.invention, Computational physics, Heat flux, law, 0103 physical sciences, Thermography, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], ddc:530, 010306 general physics, Mathematical Physics
Abstract

International audience; WEST is a full metallic tokamak with an extensive set of diagnostics for heat load measurements. In this paper, heat loads on the lower divertor of WEST are investigated using two independent methods. A first method relies on the thermal inversion of temperature measurements from arrays of thermal sensors embedded a few millimeters below the surface, while the second consists in the inversion of black body surface temperatures measured by infra-red (IR) thermography. The challenge of IR based temperature measurements in the full metal environment of WEST is addressed through a simplified model, allowing to correct for global reflections and low surface emissivities of tungsten surfaces. A large database (> 100 L-mode discharges) is investigated. It is found that the energy absorbed by an outer divertor tile during a plasma discharge is closely estimated by the two diagnostics, over a large set of experimental conditions. A similar match is also found for the peak heat flux value on the outer target. The toroidal modulation of target heat loads by magnetic ripple is found to be consistent with the geometrical projection of a parallel heat flux component. Additionally, the heat flux channel width at the target is found to scale linearly with the magnetic flux expansion as expected. These observations give confidence in the robustness of the data from both diagnostics, and confirm the simple geometrical rules at use in the description of heat flux deposition on divertor targets. However, it is shown that the heat flux channel width estimated from infra-red thermography is about three times lower than the width estimated from embedded measurements, which is still under investigation.

Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results