T. Franke E. Barbato A. Cardinali S. Ceccuzzi R. Cesario D. V. Eester E. Lerche M.-L. Mayoral F. Mirizzi M. Nightingale J.-M. Noterdaeme E. Poli A. A. Tuccillo R. Wenninger H. Zohm
The aim of driving a sufficient amount of plasma current with an appropriate radial current density profile is considered as one of the key challenges for a tokamak fusion power plant in steady state operation. Furthermore, efficient heating to enable transition to regime of enhanced confinement and to achieve breakeven plasma temperatures as well …
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 …
PublishedD. Van Eester E. Lerche T. Johnson T. Hellsten J. Ongena et al.
The constructive interference effect described by Fuchs et al. [1] shows that the mode conversion and thereby the overall heating efficiency can be enhanced significantly when an integer number of fast wave wavelengths can be folded in between the high field side fast wave cutoff and the ion-ion hybrid layer(s) at which the ion Bernstein or ion cyc…
PublishedM. Tardocchi M. Nocente I. Proverbio V. G. Kiptily P. Blanchard S. Conroy M. Fontanesi G. Grosso K. Kneupner E. Lerche A. Murari E. Perelli Cippo A. Pietropaolo B. Syme D. Van Eester G. Gorini
Intensities and detailed spectral shapes of γ-ray emission peaks were successfully reproduced using a physics model combining the kinetics of the reacting ions with a detailed description of the nuclear reaction differential cross sections for populating the L1-L8 14 N excitation levels yielding the observed γ-ray emission. The results provide a …
PublishedP. Mantica C. Angioni C. Challis G. Colyer L. Frassinetti N. Hawkes T. Johnson M. Tsalas P. C. Devries J. Weiland B. Baiocchi M. N. A. Beurskens A. C. A. Figueiredo C. Giroud J. Hobirk E. Joffrin E. Lerche V. Naulin A. G. Peeters A. Sal
New transport experiments on JET indicate that ion stiffness mitigation in the core of a rotating plasma, as described by Mantica et al. [ Phys. Rev. Lett. 102, 175002 (2009) ] results from the combined effect of high rotational shear and low magnetic shear. The observations have important implications for the understanding of improved ion core con…
PublishedR. Koch E. Lerche D. Van Eester M. Nightingale
A steady-state tokamak reactor (SSTR) requires a high efficiency current drive system, from plug to driven mega-amps. RF systems working in the ion-cyclotron range of frequencies (ICRF) have high efficiency from plug to antenna but a limited current drive (CD) efficiency and centrally peaked CD profiles. The latter feature is not adequate for a SST…
PublishedE. Lerche D. Van Eester J. Ongena M.L. Mayoral T. Johnson et al.
The non-active operation phase of ITER will be done in H|4 He plasmas at half the nominal magnetic field, B 0 =2.65T. At this field|for the given frequency range of the ICRF system (f=40-55MHz), three ICRF heating scenarios are available a priori : (i) Fundamental ICRH of majority H plasmas at f?40MHz, (ii) second harmonic (N=2) 3 He ICRH in H plas…
PublishedD. Van Eester E. Lerche A. Argouarch T. Blackman F. Durodie et al.
A set of simulation/interpretation tools based on transmission line theory and on the RF model developed by M. Vrancken [2] has been developed to study the ITER-like Antenna (ILA) at JET. For given tuning element settings, the unique solution of the equations governing the ILA circuit requires solving a system of coupled linear equations relating t…
PublishedE. Lerche V. Bobkov P. Jacquet M.L. Mayoral A. Messiaen et al.
Using the JET A2 ICRF antennas [1], experiments were carried out to assess the performance of three different dipole phasing configurations relevant for the operation of the ICRF antenna in ITER. Three similar discharges with dipole, "symmetric dipole" and "super dipole" phasings were compared. In the "super dipole" case, higher coupling was confir…
Published