Showing 1 - 8 of 8 Journals Results
2021
UKAEA-CCFE-PR(21)21
M. Fitzgerald S. E. Sharapov P. Siren E. Tholerus M. Dreval G. Szepesi P. Olivares T. Jonsson N. Fil J. Ferreira P. Rodrigues A. Figueiredo D. Borba R. Coelho F. Nabais J. Mailloux H.J.C. Oliver C. Di Troia F. Napoli Z. Stancar R. Dumont D. Keeling
In this work, we use reduced and perturbative models to examine the stability of TAEs during the ITB afterglow in JET experiments designed for the observation of alpha driven TAEs. We demonstrate that in JET-like conditions, it is sufficient to use an incompressible cold plasma model for the TAE to reproduce the experimental adiabatic features su…
Preprint2019
UKAEA-CCFE-PR(19)20
Sergei Gerasimov P. Abreu G Artaserse M. Baruzzo P. Buratti I.S. Carvalho I.H. Coffey E. de la Luna T.C. Hender R.B. Henriques R. Felton U. Kruezi P.J. Lomas P. McCullen M. Maslov E. Matveeva S. Moradi L. Piron F.G. Rimini W. Schippers G. Szepesi M. Tsalas L.E. Zakharov
The paper presents an analysis of disruptions occurring during JET-ILW plasma operations covering the period from the start of ILW (ITER-like wall) operation up to completion of JET operation in 2016. The total number of disruptions was 1951 including 466 with deliberately induced disruptions. The average disruption rate of unintended disruptions i…
Preprint Published2018
UKAEA-CCFE-PR(19)10
A. Ho J. Citrin F. Auriemma C. Bourdelle F. J. Casson Hyun-Tae Kim P. Manas G. Szepesi H. Weisen JET Contributors
This paper outlines an approach towards improved rigour in tokamak turbulence transport model validation within integrated modelling. Gaussian process regression (GPR) techniques were applied for profile fitting during the preparation of integrated modelling simulations. This allows for rigourous sensitivity tests of prescribed initial and bound…
Preprint Published2018
UKAEA-CCFE-PR(18)28
M. Fitzgerald J. Buchanan S. E. Sharapov V. G. Kiptily M. Sertoli G. Szepesi J. Boom R. Akers D. King JET contributors
Fishbones are ubiquitous in high-performance JET plasmas and are typically considered to be unimportant for scenario design. However, during recent high-performance hybrid experiments, sporadic and explosive fishbones have been observed which correlate with a reduction in performance and main chamber hotspots. Clear evidence has been obtained of fu…
Preprint Published2017
CCFE-PR(17)76
V. 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 Published2016
CCFE-PR(16)09
M. Valovič P.T. Lang A. Kirk W. Suttrop M. Cavedon G. Cseh M. Dunne L.R. Fischer L. Garzotti L. Guimarais G. Kocsis A. Mlynek B. Plőckl R. Scannell T. Szepesi G. Tardini A. Thornton E. Viezzer E. Wolfrum The ASDEX Upgrade team The EUROfusion MST1 team
The complete refuelling of the plasma density loss (pump-out) caused by mitigation of Edge Localised Modes (ELMs) is demonstrated on the ASDEX Upgrade tokamak. The plasma is refuelled by injection of frozen deuterium pellets and ELMs are mitigated by external resonant magnetic perturbations (RMPs). In this experiment relevant dimensionless paramete…
Preprint Published2014
L. Garzotti J. Figueiredo C. M. Roach M. Valovic D. Dickinson G. Naylor M. Romanelli R. Scannell G. Szepesi The Mast Team
Reactor grade plasmas are likely to be fuelled by pellet injection. This technique transiently perturbs the profiles, driving the density profile hollow and flattening the edge temperature profile. After the pellet perturbation, the density and temperature profiles relax towards their quasi-steady-state shape. Microinstabilities influence plasma co…
Published2013