J. Ball F. I. Parra
Breaking the up-down symmetry of tokamaks removes a constraint limiting intrinsic momentum transport, and hence toroidal rotation, to be small. Using gyrokinetic theory, we study the effect of different up-down asymmetric flux surface shapes on the turbulent transport of momentum. This is done by perturbatively expanding the gyrokinetic equation in…
Preprint PublishedL. Xue X. R. Duan G. Y. Zheng Y. Q. Liu Y. D. Pan S. L. Yan V. N. Dokuka V. E. Lukash R. R. Khayrutdinov
Cold and hot vertical displacement events (VDEs) are frequently related to the disruption of vertically-elongated tokamaks. The weak poloidal magnetic field around the null-points of a snowflake divertor configuration may influence the vertical displacement process. In this paper, the major disruption with a cold VDE and the vertical disruption in …
PublishedJ. Ball F. I. Parra M. Barnes
A poloidal tilting symmetry of the local nonlinear _f gyrokinetic model is demonstrated analytically and verified numerically. This symmetry shows that poloidally rotating all the flux surface shaping effects with large poloidal mode number by a single tilt angle has an exponentially small effect on the transport properties of a tokamak. This is sh…
Preprint PublishedP. Jacquet et al
Experiments have been performed under the coordination of the International Tokamak Physics Activity (ITPA) on several tokamaks, including ASDEX Upgrade (AUG), JET and DIII-D, to characterize the increased ICRF antenna loading achieved by optimizing the position of gas injection relative to the RF antennas. On DIII-D, AUG and JET (with the ITER-Lik…
Preprint PublishedS.Y. Allan S. Elmore G. Fishpool B. Dudson The MAST Team The EUROFusion MST1 Team
Retarding field energy analysers (RFEAs) have been used to compare the ion temperature ( T i ) of large plasma filaments with the background plasma (composed of small scale filaments) at the midplane and divertor target in L mode discharges in the Mega Amp Spherical Tokamak (MAST). At low densities, at the midplane and divertor, at distances from 2…
Preprint PublishedJ. C. Hillesheim E. Delabie H. Meyer C. F. Maggi L. Meneses E. Poli JET Contributors
High spatial resolution Doppler backscattering measurements in JET have enabled new insights into the development of the edge . We observe fine-scale spatial structures in the edge well with a wave number kr ? i ˜ 0.4–0.8, consistent with stationary zonal flows, the characteristics of which vary with density. The zonal flow amplitude and wavelen…
Preprint PublishedM. E. A. Coury S. L. Dudarev W. M. C. Foulkes A. P. Horsfield Pui-Wai Ma J. S. Spencer
Hubbard-like Hamiltonians are widely used to describe on-site Coulomb interactions in magnetic and stronglycorrelated solids, but there is much confusion in the literature about the form these Hamiltonians should take for shells of p and d orbitals. This paper derives the most general s , p , and d orbital Hubbard-like Hamiltonians consistent with …
Preprint PublishedA. De Backer A. Sand C.J. Ortiz C. Domain P. Olsson E. Berthod C.S. Becquart
The damage produced by primary knock-on atoms (PKA) in W has been investigated from the threshold displacement energy (TDE) where it produces one Self Interstitial Atom (SIA) – vacancy pair to larger energies, up to 100 keV, where a large molten volume is formed. The TDE has been determined in different crystal directions using the Born Oppenheim…
Preprint PublishedS. Wiesen M. Groth S. Brezinsek M. Wischmeier JET contributors
An overview is given on the recent progress on edge modelling activities for the JET ITER like wall using the computational tools like the SOLPS or EDGE2D-EIRENE code. The validation process of these codes on JET with its metallic plasma-facing components is an important step towards predictive studies for ITER and DEMO in relevant divertor operati…
Preprint PublishedA. Widdowson A. Baron-Wiechec P. Batistoni E. Belonohy J.P. Coad P. Dinca D. Flammini F. Fox K Heinola I. Jepu J. Likonen S. Lilley C.P. Lungu G.F. Matthews J. Naish O. Pompilian C. Porosnicu M. Rubel R. Villari JET Contributors
JET components are removed periodically for surface analysis to assess material migration and fuel retention. This paper describes issues related to handling JET components and procedures for preparing samples for analysis; in particular a newly developed procedure for cutting beryllium tiles is presented. Consideration is also given to the hazards…
Preprint Published