M. Maslov J. Citrin P. Jacquet Y. Kazakov D. L. Keeling D. B. King E. Lerche M. Marin J. Ongena D. Van Eester
As part of the preparation for the second JET DT campaign (DTE2), a series of isotope control experiments in H/D mixtures [1] have shown that NBI fuelling species has only a weak effect on the core isotope composition, which remains determined by the edge H/D ratio and therefore by the injected gas.
Preprint PublishedC.D. Challis S. Brezinsek I. Coffey N. Hawkes D. Keeling D. King G. Pucella E. Viezzer JET Contributors
The initial Ohmic current ramp phase of JET hybrid plasmas, including a current ‘overshoot’ before the main heating, is used to optimise the q-profile shape to allow access to high β and avoid MHD instabilities [1]. Such hybrid plasmas have never been operated using tritium (T) or mixed deuterium-tritium (D-T) fuel. However, experiments with i…
Preprint PublishedL. Horvath C.F. Maggi A. Chankin S. Saarelma A.R. Field E. Belonohy A. Boboc G. Corrigan E.G. Delabie J. Flanagan L. Frassinetti C. Giroud D. Harting D. Keeling D. King M. Maslov G.F. Matthews S. Menmuir S.A. Silburn J. Simpson A.C.C Sips H. Weisen K.J. Gibson JET Contributors
The pedestal structure, ELM losses and linear MHD stability are analysed in a series of JET-ILW H and D type I ELMy H-mode plasmas. The pedestal pressure (pPED) is typically higher in D than in H at the same input power, with the difference mainly due to lower density in H than in D. At the same input power, the pedestal electron pres…
Preprint PublishedI. Turner R. McAdams W. Arter A. Ash M. Barnard D. Ciric I. Day D. Keeling D. King C. Lane M. Nicassio T. Robinson A. Shepherd J. Zacks
Increased neutralisation and hence injected neutral beam power can be achieved by increasing the neutraliser target. This has the potential to increase the loading on the ion source backplate due to backstreaming electrons. Measurements of the backplate power loading due to backstreaming electrons are presented for the JET EP2 neutral beam injector…
Preprint PublishedD.B. King C.D. Challis E.G. Delabie D. Keeling G.F. Matthews S. Silburn JET contributors
The dependence of JET neutron deficit and energy balance on neutral beam (PINI) selection has been investigated experimentally. The discrepancy between neutrons predicted and measured during JET pulses has consistently deviated, with the measured neutrons typically being lower than expected by simulation. A number of investigations into this hav…
Preprint PublishedD. Gallart M. Mantsinen C. Challis D. Frigione J. Graves E. Belonohy F. Casson A. Czarnecka J. Eriksson J. Garcia M. Goniche C. Hellesen J. Hobirk P. Jacquet E. Joffrin N. Krawczyk D. King M. Lennholm E. Lerche E. Pawelec X. Sáez M. Sertoli G. Sips E. Solano M. Tsalas P. Vallejos Olivares M. Valisa
During the 2015-2016 JET campaigns many efforts have been devoted to the exploration of high-performance plasma scenarios envisaged for DT operation in JET. In this paper we review various key recent hybrid discharges and model the combined ICRF+NBI heating. These deuterium discharges with deuterium beams had the ICRF antenna frequency tuned to mat…
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…
Preprint PublishedM. Maslov D. King E. Viezzer D. Keeling C. Giroud T. Tala A. Salmi M. Marin J. Citrin C. Bourdelle E. Solano JET contributors
Particle transport is of a great importance for understanding physics of tokamak plasmas and planning future experiments on larger machines such as ITER. The subject was intensively studied in the past, particularly in relation to density peaking and presence of anomalous inward particle convection in L- and H-mode. While in the L-mode case presenc…
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 PublishedL. Piron B. Zaniol D. Bonfiglio L. Carraro A. Kirk L. Marrelli R. Martin C. Piron P. Piovesan M. Zuin
This work presents the first evidence of helical flow in RFX-mod q(a) < 2 tokamak plasmas. The flow pattern is characterized by the presence of convective cells with m = 1 and n = 1 periodicity in the poloidal and toroidal direction, respectively. A similar helical flow deformation has been observed in the same device when operatedfas a Reversed…
Preprint Published