M. Fitzgerald R. Dumont D. Keeling J. Mailloux S. Sharapov M. Dreval A. Figueiredo R. Coelho J. Ferreira P. Rodrigues F. Nabais D. Borba Ž. Štancar G. Szepesi R.A. Tinguely N Fil P.G. Puglia H.J.C. Oliver V. Kiptily M. Baruzzo M. Lennholm P. Siren J. Garcia C.F. Maggi
A toroidal Alfven eigenmode (TAE) has been observed driven by alpha particles in the Joint European Torus (JET). The observation was made in dedicated deuterium-tritium experiments where radio-frequency (RF) heating was absent, in the so-called “afterglow” period when neutral beam heating was removed. Agreement with reduced and perturbative mod…
PreprintR. B. Morales A. Salmi P. Abreu C. H. S. Amador P. Carman J. Fessey J. Flanagan M. Fontana C. Giroud S. Hacquin S. Heuraux L. Meneses R. Sabot A. Silva A. Sirinelli G. Szepesi D. Taylor D. Terranova
JET’s frequency-modulated continuous-wave (FMCW) reflectometers have been operating well with the current design since 2005 and density profiles are being automatically calculated intershot since then[1]. However, the calculated profiles had long suffered from several shortcomings – poor agreement to other diagnostics; sometimes inappropriat…
PreprintM. Kong E. Nardon M. Hoelzl D. Bonfiglio D. Hu U. Sheikh A. Boboc P. Carvalho T.C. Hender S. Jachmich K.D. Lawson S. Silburn Ž. Štancar R. Sweeney G. Szepesi the JOREK team JET contributors
Shattered pellet injection (SPI), with research started in recent years, is the current concept for the ITER disruption mitigation system (DMS) to prevent disruption-related damage. Compared with impurity SPI, pure deuterium (D2) SPI could contribute to runaway electron (RE) avoidance in ITER via a strong dilution cooling before the thermal quen…
PreprintG. Szepesi L.C. Appel E. de la Luna L. Frassinetti P. Gaudio M. Gelfusa S. Gerasimov N.C. Hawkes M. Sertoli D. Terranova
Many of the essential data analysis procedures for a tokamak experiment rely on the knowledge of the magnetic field structure obtained from MHD force balance. On JET, the code that is responsible for computing the magnetic equilibrium is called EFIT++. Interpretation of JET data has been challenging due to inconsistencies between diagnostic meas…
PreprintC. Giroud S. Brezinsek R. Pitts I.S. Carvalho A. Huber E. Kaveeva D. Keeling J. Mailloux S. Aleiferis B. Chapman S. Henderson L. Garzotti E. Lerche M. MArin M. Maslov M. Brix P. Carvalho I. Coffey J. Fontdecaba L. Horvath I. Jepu J. Karhunen E. Litherland-Smith A. Meigs R.B. Morales T. Pereira D. Refy Z. Stancar M. Sertoli S. Silburn G. Szepesi A. Thorman M. Tomes I. Veselova B. Viola S. Wiesen JET contributors,
JET has investigated one the key issues for the baseline scenario in ITER, the integration of a radiative divertor for heat load control with the use of neon and nitrogen as seed impurity. A characterization of the choice of the impurity seed on plasma confinement, neutrons, pedestal MHD stability, pedestal instabilities, core transport is given…
PreprintM. 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…
PreprintS.N. Gerasimov G Artaserse P. Buratti I.S. Carvalho E. de la Luna T.C. Hender R.B. Henriques P.J. Lomas E. Matveeva S. Moradi L. Piron F.G. Rimini G. Szepesi L.E. Zakharov JET Contributors
An n = 1 locked, or slowly rotating, mode has been observed in most pulses prior to JET disruptions. However, a small fraction of non-disruptive pulses has a locked mode which eventually vanishes without disruption. Hence, on JET the locked mode amplitude is routinely used as an indicator of unhealthy plasma. There are two threshold levels…
Preprint PublishedSergei 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 PublishedA. 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 PublishedM. 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…
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