F. G. Rimini D. Alves G. Arnoux M. Baruzzo E. Belonohy I. Carvalho R. Felton E. Joffrin P. Lomas P. McCullen A. Neto I. Nunes C. Reux A. Stephen D. Valcarcel S. Wiesen JET EFDA contributors
The JET tokamak is unique amongst present fusion devices in its capability to operate at high plasma current, providing the closest plasma parameters to ITER. The physics benefits of high current operation have to be balanced against the risks to the integrity of the machine due to high force disruptions. The installation of the ITER-Like Wall (ILW…
Preprint PublishedC.F. Maggi S. Saarelma F.J. Casson C. Challis E. de la Luna L. Frassinetti C. Giroud E. Joffrin J. Simpson M. Beurskens I. Chapman J. Hobirk M. Leyland P. Lomas C. Lowry I. Nunes F. Rimini A.C.C. Sips H. Urano JET Contributors
New experiments in 2013-2014 have investigated the physics responsible for the decrease in H-mode pedestal confinement observed in the initial phase of JET-ILW operation (2012 Experimental Campaigns). The effects of plasma triangularity, global beta and neutrals on pedestal confinement and stability have been investigated systematically. The stabil…
Preprint PublishedE. Lerche M. Goniche P. Jacquet D. Van Eester V. Bobkov L. Colas A. Czarnecka S. Brezinsek M.Brix K. Crombe M. Graham M. Groth I. Monakhov T. Mathurin G. Matthews L. Meneses C. Noble V. Petrzilka F. Rimini A. Shaw JET-EFDA Contributors
Recent JET-ILW [1,2] experiments reiterated the importance of tuning the plasma fuelling in order to optimize ion cyclotron resonance frequency (ICRF) heating in high power H-mode discharges. By fuelling the plasma from gas injection modules (GIMs) located in the midplane and on the top of the machine instead of adopting the more standardly used di…
Preprint PublishedE. Lerche M. Goniche P. Jacquet D. Van Eester V. Bobkov L. Colas I. Monakhov F. Rimini A. Czarnecka K. Crombé R. Dumont J. Hobirk Y. Kazakov M.-L. Mayoral L. Meneses J. Mlynar C. Noble I. Nunes J. Ongena V. Petrzilka M. Reich M. Santala
Ion cyclotron resonance frequency (ICRF) heating has been an essential component in the development of high power H-mode scenarios in JET-ILW. The steps that were taken for the successful use of ICRF heating in terms of enhancing the power capabilities and optimizing the heating performance in view of core impurity mitigation in these experiments w…
Preprint PublishedE. Lerche D. Van Eester Y. Kazakov P. Jacquet I. Monakhov M. Goniche L. Colas F. Rimini K. Crombé R. Dumont V. Kiptily M. Santala JET Contributors
Heating single ion species plasmas with ICRF is a challenging task: Fundamental ion cyclotron heating (w = w ci ) suffers from the adverse polarization of the RF electric fields near the majority cyclotron resonance while second harmonic heating (w = 2w ci ) typically requires pre-heating of the plasma ions to become efficient. Recently, w = 2w ci …
Preprint PublishedK. K. Kirov Yu. Baranov E. Barbato M. Brix G. Corrigan A. Ekedahl M. Goniche J. Mailloux V. Petrzilka F. Rimini M. Stamp JET EFDA Contributors
An overview of the recent results of Lower Hybrid (LH) experiments at JET with the ITER-like wall (ILW) is presented. Topics relevant to LH wave coupling are addressed as well as issues related to ILW and LH system protections. LH wave coupling was studied in conditions determined by ILW recycling and operational constraints. It was concluded that …
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…
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…
PublishedC. Giroud G.P. Maddison S. Jachmich F. Rimini M. Beurskens I. Balboa S. Brezinsek R. Coelho J.W.Coenen Et Al
This paper reports the impact on confinement and power load of the high-shape 2.5MA ELMy H-mode scenario at JET of a change from an all carbon plasma facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding…
PublishedK.K. Kirov J. Mailloux A. Ekedahl V. Petrzilka G. Arnoux Yu. Baranov M. Brix M. Goniche S. Jachmich M.-L. Mayoral J. Ongena F. Rimini M. Stamp JET EFDA Contributors
In this paper important aspects of Lower Hybrid (LH) operation with the ITER Like Wall (ILW) [1] at JET are reported. Impurity release during LH operation was investigated and it was found that there is no significant Be increase with LH power. Concentration of W was analysed in more detail and it was concluded that LH contributes negligibly to its…
Published