A. 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…Published
D. 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…Published
P. 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 …Published
L. 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…Published
P. Jacquet G. Arnoux L. Colas L. Delpech A. Ekedahl et al.
In recent JET experiments, Lower Hybrid (LH) power losses in the Scrape-Off Layer (SOL) were characterized using infra-red (IR) thermography. Hot spots were observed on objects intercepting the field lines passing in front of the LH launcher, i.e. on poloidal limiters and on dumplates located at the top of the tokamak; their locations being in good…Published
K. Vulliez L. Colas A. Argouarch A. Mendes C. Hamlynharris et al.
In the framework of the Ion Cyclotron (IC) developments held in Cadarache, the design of a new Faraday Screen (FS) was initiated to replace the aging ones mounted on the 3 Tore Supra (TS) antennas. The new conceptual design proposed is steered by conclusive results of electrical simulation stressing the need to suppress the parallel RF currents flo…Published
L. Colas Ph. Jacquet G. Agarici C. Portafaix M. Goniche
RF-sheath induced heat loads are identified from infrared thermography measurements on Tore Supra ITER-like prototype and JET A2 antennae, and are quantified by fitting thermal calculations. Using a simple scaling law assessed experimentally, the estimated heat fluxes are then extrapolated to the ITER ICRF launcher delivering 20MW RF power for seve…Published
V. Bobkov R. Bilato F. Braun L. Colas R. Dux et al.
W sputtering during ICRF on ASDEX Upgrade (AUG) and temperature rise on JET A2 antenna septa are considered in connection with plasma conditions at the antenna plasma facing components and E|| near-fields. Large antenna-plasma clearance, high gas puff and low light impurity content are favorable to reduce W sputtering in AUG. The spatial distributi…Published
A. Ekedahl L. Colas M.L. Mayoral B. Beaumont Ph. Bibet et al.
Combined operation of Lower Hybrid (LH) and Ion Cyclotron Resonance Frequency (ICRF) waves can result in a degradation of the LH wave coupling, as observed both in the Tore Supra and JET tokamaks. The reflection coefficient on the part of the LH launcher magnetically connected to the powered ICRF antenna increases, suggesting a local decrease in th…Published