Visible spectroscopy diagnostics for tungsten source assessment in the WEST tokamak: First measurements

Conference · Sun Jul 01 00:00:00 EDT 2018 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.5035566· OSTI ID:1515657

Meyer, O. ^[1]; Giacalone, J ^[1]; Gouin, A ^[1]; Pascal, Jean-Yves ^[2]; Klepper, C Christopher  ^[3]; Fedorczak, N. ^[1]; Lotte, P.H. ^[1]; Unterberg, Ezekial  ^[3]; Fehling, Dan T. ^[3]; Harris, Jeffrey  ^[3]

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1. French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance
2. CEA IRFM, St. Paul-lez-Durance, France
3. ORNL

The present work concerns the measurements obtained with the Tungsten (W) Environment in Steady-state Tokamak (WEST) visible spectroscopy system during the first experimental campaign. This system has been developed in the framework of the WEST project that equipped the existing Tore Supra device with a tungsten divertor in order to test actively cooled tungsten Plasma Facing Components (PFC) in view of preparing for ITER operation. The goal of this diagnostic is to measure the PFC sources and the deuterium recycling with spectral, spatial, and temporal resolution adapted to the predicted power deposition profiles on the objects observed. Three kinds of PFCs are monitored: the Ion Cyclotron Resonance Heating (ICRH) antenna and Low Hybrid Current Drive (LHCD) launcher W limiters; one of the 6 W inner bumpers; and the upper and lower W divertors. Large-aperture in-vessel actively cooled optical systems (f-number ~ 3) were installed for each view and connected to optical fibres. A total of 240 optical fibers can be distributed on various detection systems including a fast response-time, multi-channel, filtered photodetector-based “Filterscope” system, developed by Oak Ridge National Laboratory (USA) as well as grating spectrometers optimized for multi-sightline analysis. The first WEST experimental campaign conducted in 2017 has been dedicated to plasma start-up development during which the visible spectroscopy system has provided crucial information related to the impurity content first and then impurity sources. The diagnostic setup for that first experimental campaign was limited to the inner bumper and outer limiters but was sufficient to demonstrate that the optical setup was in accordance with the specifications. The radiance calibration procedure allowed us to estimate fluxes from the main limiter of about 8 × 10¹⁸ atoms/(s m²) and to show a first W source radial profile along the outboard limiter.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1515657
• Journal Information: Review of Scientific Instruments, Vol. 89, Issue 10; Conference: 22nd Biannual Topical Conference on High-Temperature Plasma Diagnostics (HTPD) - General Atomics , San Diego, CA, California, United States of America , 4/16/2018-4/19/2018; ISSN 0034-6748
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English