Publications (140) View all
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Article: Development of a mirror-based endoscope for divertor spectroscopy on JET with the new ITER-like wall (invited).
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ABSTRACT: A new endoscope with optimised divertor view has been developed in order to survey and monitor the emission of specific impurities such as tungsten and the remaining carbon as well as beryllium in the tungsten divertor of JET after the implementation of the ITER-like wall in 2011. The endoscope is a prototype for testing an ITER relevant design concept based on reflective optics only. It may be subject to high neutron fluxes as expected in ITER. The operating wavelength range, from 390 nm to 2500 nm, allows the measurements of the emission of all expected impurities (W I, Be II, C I, C II, C III) with high optical transmittance (≥30% in the designed wavelength range) as well as high spatial resolution that is ≤2 mm at the object plane and ≤3 mm for the full depth of field (±0.7 m). The new optical design includes options for in situ calibration of the endoscope transmittance during the experimental campaign, which allows the continuous tracing of possible transmittance degradation with time due to impurity deposition and erosion by fast neutral particles. In parallel to the new optical design, a new type of possibly ITER relevant shutter system based on pneumatic techniques has been developed and integrated into the endoscope head. The endoscope is equipped with four digital CCD cameras, each combined with two filter wheels for narrow band interference and neutral density filters. Additionally, two protection cameras in the λ > 0.95 μm range have been integrated in the optical design for the real time wall protection during the plasma operation of JET.The Review of scientific instruments 10/2012; 83(10):10D511. · 1.52 Impact Factor -
Article: Plasma facing materials for the JET ITER-like Wall
Fusion Science and Technology 01/2012; ICFRM-15 special issue.. · 1.12 Impact Factor -
Article: JET ITER-like wall—overview and experimental programme
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ABSTRACT: This paper reports the successful installation of the JET ITER-like wall and the realization of its technical objectives. It also presents an overview of the planned experimental programme which has been optimized to exploit the new wall and other JET enhancements in 2011/12.Physica Scripta 12/2011; 2011(T145):014001. · 1.20 Impact Factor -
Article: Material performance of tungsten coatings under transient heat loads
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ABSTRACT: Transient thermal loads in magnetic confinement experiments such as ITER have a strong impact on the material degradation of the plasma-facing components. In particular, the thermal loads for plasma-facing components in nuclear fusion devices are extraordinarily high. Within the ITER-like wall project, realized at JET, some of the plasma-facing components in the divertor region are made of tungsten-coated carbon fiber composite (CFC). These tungsten coatings were tested under ELM (edge-localized modes)-like loading conditions in an electron beam material testing facility to determine the thermal shock resistance. The failure occurrence and damage thresholds depending on base temperature and absorbed power density with special emphasis on the microstructure of the underlying CFC substrate are described in detail.Physica Scripta 12/2011; 2011(T145):014059. · 1.20 Impact Factor -
Article: ICRF heating at JET: From operations with a metallic wall to the long term perspective of a DT campaign
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ABSTRACT: The first series of experiments with the ITER-like wall (ILW) will start mid-2011 with D plasmas and will continue through 2012-13 with H, 4He and D plasmas, and up to 2014-15, when a DT campaign is proposed. In this paper, the previous experience at JET is reviewed to set the scene for the future challenges of ICRF operation including change in the ICRF coupling, W impurity production and evaluation of localized power loads due the RF sheaths. development in a Beryllium/Tungsten environment of ICRF heating schemes for the non activated and the DT phases of ITER.11/2011; 1406:253-256.
