Krassimir Kirov Yu. Baranov I.S. Carvalho C.D. Challis J. Eriksson D. Frigione L. Garzotti J. Graves P. Jacquet D.L. Keeling E. Lerche P.J. Lomas C. Lowry M. Mantsinen F. Rimini and JET Contributors
Fast ion synergistic effects were studied by predictive modelling of JET best performing pulses for various levels of Neutral Beam (NB) and Radio Frequency (RF) power. Calculated DD neutron yields were analysed with the intention of separating the impact of sheer synergistic effects due to changes in fast ion (FI) distribution function (DF) from su…
Preprint PublishedS. Breton F.J. Casson C. Bourdelle J. Citrin Y. Baranov Y. Camenen C. Challis J. Garcia G. Corrigan L. Garzotti S. Henderson F. Koechl M. OMullane T. Puetterich M. Sertoli M. Valisa JET contributors
For the first time, over five confinement times, the self-consistent flux driven time evolution of heat, momentum transport and particle fluxes of electrons and multiple ions including Tungsten (W) is modeled within the integrated modeling platform JETTO [Romanelli M et al PFR 2014], using first principle-based codes : namely, QuaLiKiz [Bourd…
Preprint PublishedDL Keeling CD Challis I Jenkins NC Hawkes I Lupelli C Michael MFM. de Bock the MAST Team JET contributors
Experiments have been carried out on the MAST and JET tokamaks intended to compare the electrical resistivity of the plasma with theoretical formulations. The tests consist of obtaining motional stark effect (MSE) measurements in MHD-free plasmas during plasma current ramp-up (JET and MAST), ramp-down (MAST) and in stationary state (JET and MAST). …
Preprint PublishedV. G. Kiptily M. Fitzgerald V. Goloborodko S. E. Sharapov C. D. Challis D. Frigione J. Graves M. J. Mantsinen P. Beaumont M. Garcia-Munoz C. Perez von Thun J. F. R. Rodriguez D. Darrow D. Keeling D. King K. G. McClements E. Solano S. Schmuck G. Sips G. Szepesi JET contributors
During development of a high-performance hybrid scenario for future deuterium–tritium experiments on the Joint European Torus, an increased level of fast ion losses in the MeV energy range was observed during the instability of high-frequency n = 1 fishbones. The fishbones are excited during deuterium neutral beam injection combined with…
Preprint PublishedI. Jenkins C.D. Challis D.L. Keeling E. Surrey
Engineering and technical constraints on Neutral Beam Injection (NBI) in DEMO may determine the available beam energy and may also strongly impact the Neutral Beam Current Drive (NBCD) efficiency by restricting available beam tangential radii. These latter are determined by factors such as the inter-TF coil spacing, as well as the degree of requir…
Preprint PublishedD. L. Keeling T. R. Barrett M. Cecconello C. D. Challis N. Hawkes O. M. Jones I. Klimek K. G. McClements A. Meakins J. Milnes M. Turnyanskiy The MAST team
The phenomenon of redistribution of neutral beam fast-ions due to MHD activity in plasma has been observed on many tokamaks and more recently has been a focus of research on MAST ( Turnyanskiy M. et al, 2013 Nucl. Fusion 53 053016 ). n=1 fishbone modes are observed to cause a large decrease in the neutron emission rate indicating to exist a signifi…
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 PublishedC.D. Challis J. Garcia M. Beurskens P. Buratti E. Delabie P. Drewelow L. Frassinetti C. Giroud N. Hawkes J. Hobirk E. Joffrin D. Keeling D.B. King C.F. Maggi J. Mailloux C. Marchetto D. McDonald I. Nunes G. Pucella S. Saarelma J. Simps
The replacement of the JET carbon wall (C-wall) by a Be/W ITER-like wall (ILW) has affected the plasma energy confinement. To investigate this, experiments have been performed with both the C-wall and ILW to vary the heating power over a wide range for plasmas with different shapes. It was found that the power degradation of thermal energy confinem…
Preprint PublishedS. Saarelma A. Järvinen M. Beurskens C. Challis L. Frassinetti C. Giroud M. Groth M. Leyland C. Maggi J. Simpson JET Contributors
The H-mode pedestal plays an important role in determining global confinement in tokamaks. In high triangularity H-mode experiments in Joint European Torus with the ITER-like wall (JET-ILW), significantly higher pedestal temperature and global confinement have been achieved with nitrogen seeding. The experimentally observed increase in pedestal hei…
Preprint PublishedM-L. Mayoral V. Bobkov A. Czarnecka I. Day A. Ekedahl P. Jacquet M. Goniche R. King K. Kirov E. Lerche J. Mailloux D. Van Eester O. Asunta C. Challis D. Ciric J.W. Coenen L. Colas C. Giroud M. Graham I. Jenkins E. Joffrin T. Jones D.
The major aspects linked to the use of the JET auxiliary heating systems: NBI, ICRF and LHCD, in the new JET ITER-like wall (JET-ILW) are presented. We show that although there were issues related to the operation of each system, efficient and safe plasma heating was obtained with room for higher power. For the NBI up to 25.7MW was safely injected;…
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