P. Jacquet V. Bobkov S. Brezinsek M. Brix A-L. Campergue L. Colas A. Czarnecka P. Drewelow M. Graham C. C. Klepper E. Lerche M.-L. Mayoral A. Meigs D. Milanesio I. Monakhov J. Mlynar T. Pütterich A. Sirinelli D. Van-Eester JET-EFDA
In 2011/12, JET started operation with its new ITER-Like Wall (ILW) made of a tungsten (W) divertor and a beryllium (Be) main chamber wall. The impact of the new wall material on the JET Ion Cyclotron Resonance Frequency (ICRF) operation was assessed and also the properties of JET plasmas heated with ICRF were studied. No substantial change of the …
PublishedA.-L. Campergue P. Jacquet V. Bobkov D. Milanesio I. Monakhov L. Colas G. Arnoux M. Brix A. Sirinelli JET-EFDA Contributors
When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced power deposition on Plasma-Facing Components (PFCs) close to the antennas can occur. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat fluxes on the protection of the JET ICRF antennas, using Infra-Red (IR) thermography me…
PublishedE. Lerche D. Van Eester Ph. Jacquet M.-L. Mayoral V. Bobkov L. Colas A. Czarnecka M. Graham G. Matthews I. Monakhov R. Neu T. Puetterich F. Rimini P. De Vries JET-EFDA Contributors
After the change over from the C-wall to the ITER-like Be/W wall (ILW) in JET, the radiation losses during ICRF heating have increased and are now substantially larger than those observed with NBI at the same power levels, in spite of the similar global plasma energies reached with the two heating systems. A comparison of the NBI and ICRF performan…
PublishedM.-L. Mayoral T. Pütterich P. Jacquet E. Lerche D. Van-Eester V. Bobkov C. Bourdelle L. Colas A. Czarnecka J. Mlynar R. Neu JET-EFDA Contributors
During the initial operation of the JET ITER-like wall, particular attention was given to the characterization of the Ion Cyclotron Resonance Frequency (ICRF) heating in this new metallic environment. In this contribution we compare L-modes plasmas heated by ICRF or by Neutral Beam Injection (NBI). ICRF heating as expected led to a much higher cent…
PublishedA. Czarnecka V. Bobkov I. H. Coffey L. Colas P. Jacquet K. D. Lawson E. Lerche C. Maggi M.-L. Mayoral T. Pütterich D. Van Eester JET-EFDA Contributors
Magnetically confined plasmas, such as those produced in the tokamak JET, contain measurable amounts of impurity ions produced during plasma-wall interactions (PWI) from the plasma-facing components and recessed wall areas. The impurities, including high- and mid-Z elements such as tungsten (W) from first wall tiles and nickel (Ni) from Inconel str…
PublishedD. Van Eester E. Lerche P. Jacquet V. Bobkov A. Czarnecka J. W. Coenen L. Colas K. Crombé M. Graham S. Jachmich E. Joffrin C. C. Klepper V. Kiptily M. Lehnen C. Maggi F. Marcotte G. Matthews M.-L. Mayoral K. McCormick I. Monakhov M. F. F. Nave, R. Neu, C. Noble, J. Ongena, T. Pütterich, F. Rimini, E. R. Solano, G. van Rooij, and JET-EFDA contributors
The most recent JET campaign has focused on characterizing operation with the "ITER-like" wall. One of the questions that needed to be answered is whether the auxiliary heating methods do not lead to unacceptably high levels of impurity influx, preventing fusion-relevant operation. In view of its high single pass absorption, hydrogen minority funda…
PublishedI Monakhov M Graham T Blackman S Dowson F Durodie P Jacquet J Lehmann M-L Mayoral M P S Nightingale C Noble H Sheikh M Vrancken A Walden A Whitehurst E Wooldridge JET-EFDA Contributors
A load-tolerant External Conjugate-T (ECT) impedance matching system for two A2 Ion Cyclotron Resonance Heating (ICRH) antennas has been successfully put into operation at JET. The system allows continuous injection of the RF power into plasma in the presence of strong antenna loading perturbations caused by Edge Localized Modes (ELMs). Reliable EC…
PublishedP. Jacquet F. Marcotte L. Colas G. Arnoux V. Bobkov Y. Corre S. Devaux J-L. Gardareine E. Gauthier M. Graham E. Lerche M-L. Mayoral I. Monakhov F.Rimini A. Sirinelli D. Van Eester JET EFDA Contributors
When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced heat-fluxes are commonly observed on some plasma facing components close to the antennas. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat flux to the JET ICRF antennas. Using Infra-Red thermography and thermal models of …
PublishedL. Colas Ph. Jacquet M.L. Mayoral G. Arnoux V. Bobkov et al.
Heat loads from ICRF and LH wave absorption in the SOL are characterized on JET from the de-convolution of surface temperatures measured by infrared thermography. The spatial localization, quantitative estimates, parametric dependence and physical origin of the observed heat fluxes are documented. Implications of these observations are discussed fo…
PublishedP. Jacquet G. Bergerby V. Bobkov T. Blackman I. E. Day et al.
When testing the SHAD system on JET ICRF antennas, parasitic signals in the detection band (5-20MHz) were detected. We have identified emission from grid breakdown events in the Neutral Beam injectors, and Ion Cyclotron Emission from the plasma. Spurious signals in the band 4-10 MHz are also often observed at the onset of ELM events. Such parasitic…
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