TY - JOUR
T1 - Scenario development for D–T operation at JET
JF - Nuclear Fusion
Y1 - 2019
A1 - Garzotti, L.
A1 - Challis, C.
A1 - Dumont, R.
A1 - Frigione, D.
A1 - Graves, J.
A1 - Lerche, E.
A1 - Mailloux, J.
A1 - Mantsinen, M.
A1 - Rimini, F.
A1 - Tsalas, M.
A1 - Casson, F.
A1 - Czarnecka, A.
A1 - Eriksson, J.
A1 - Felton, R.
A1 - Frassinetti, L.
A1 - Gallart, D.
A1 - J. Garcia
A1 - Giroud, C.
A1 - Joffrin, E.
A1 - Kim, H. T.
A1 - Krawczyk, N.
A1 - Lennholm, M.
A1 - Lomas, P.
A1 - Lowry, C.
A1 - Meneses, L.
A1 - Nunes, I.
A1 - Roach, C. M.
A1 - Romanelli, M.
A1 - Sharapov, S.
A1 - Silburn, S.
A1 - Sips, G.
A1 - Stefanikova, E.
A1 - Valcárcel, D. F.
A1 - Valovic, M.
A1 - JET Contributors
AB - The JET exploitation plan foresees D–T operations in 2020 (DTE2). With respect to the first D–T campaign in 1997 (DTE1), when JET was equipped with a carbon wall, the experiments will be conducted in presence of a beryllium–tungsten ITER-like wall and will benefit from an extended and improved set of diagnostics and higher additional heating power (32 MW neutral beam injection + 8 MW ion cyclotron resonance heating). There are several challenges presented by operations with the new wall: a general deterioration of the pedestal confinement; the risk of heavy impurity accumulation in the core, which, if not controlled, can cause the radiative collapse of the discharge; the requirement to protect the divertor from excessive heat loads, which may damage it permanently. Therefore, an intense activity of scenario development has been undertaken at JET during the last three years to overcome these difficulties and prepare the plasmas needed to demonstrate stationary high fusion performance and clear alpha particle effects. The paper describes the status and main achievements of this scenario development activity, both from an operational and plasma physics point of view.
VL - 59
IS - 7
U1 - FP
U2 - TP
U5 - d9b15e69bfe1a729038a69b113dc934d
ER -
TY - JOUR
T1 - Modelling of JET hybrid plasmas with emphasis on performance of combined ICRF and NBI heating
JF - Nuclear Fusion
Y1 - 2018
A1 - Gallart, D.
A1 - Mantsinen, M. J.
A1 - Challis, C.
A1 - Frigione, D.
A1 - Graves, J.
A1 - Belonohy, E.
A1 - Casson, F.
A1 - Czarnecka, A.
A1 - Eriksson, J.
A1 - Tsalas, M.
A1 - J. Garcia
A1 - Goniche, M.
A1 - Hellesen, C.
A1 - Hobirk, J.
A1 - Jacquet, P.
A1 - Joffrin, E.
A1 - Krawczyk, N.
A1 - King, D.
A1 - Lennholm, M.
A1 - Lerche, E.
A1 - Pawelec, E.
A1 - Saez, X.
A1 - Sertoli, M.
A1 - Sips, G.
A1 - Solano, E.
A1 - Vallejos, P.
A1 - Valisa, M.
A1 - JET Contributors
AB - 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 match the cyclotron frequency of minority H at the centre of the tokamak coinciding with the second harmonic cyclotron resonance of D. The modelling takes into account the synergy between ICRF and NBI heating through the second harmonic cyclotron resonance of D beam ions, allowing us to assess its impact on the neutron rate R NT. For discharges carried out with a fixed ICRF antenna frequency and changing toroidal magnetic field to vary the resonance position, we evaluate the influence of the resonance position on the heating performance and central impurity control. The H concentration is varied between discharges in order to test its role in the heating performance. It is found that discharges with a resonance beyond ~0.15 m from the magnetic axis R 0 suffer from MHD activity and impurity accumulation in these plasma conditions. According to our modelling, the ICRF enhancement of R NT increases with the ICRF power absorbed by deuterons as the H concentration decreases. We find that in the recent hybrid discharges, this ICRF enhancement varies due to a variation of H concentration and is in the range of 10%–25%. The modelling of a recent record high-performance hybrid discharge shows that ICRF fusion yield enhancement of ~30% and ~15% respectively can be achieved in the ramp-up phase and during the main heating phase. We extrapolate the results to DT and find that the best performing hybrid discharges correspond to an equivalent fusion power of ~7.0 MW in DT. Finally, an optimization analysis of the bulk ion heating for the DT scenario reveals around 15%–20% larger bulk ion heating for the 3He minority scenario as compared to the H minority scenario.
VL - 58
IS - 10
U1 - FP
U2 - TP
U5 - 4da08865ab28a340661ee07615fca105
ER -
TY - JOUR
T1 - ELM frequency feedback control on JET
JF - Nuclear Fusion
Y1 - 2015
A1 - Lennholm, M.
A1 - Beaumont, P. S.
A1 - Carvalho, I. S.
A1 - Chapman, I.T.
A1 - Felton, R.
A1 - Frigione, D.
A1 - Garzotti, L.
A1 - Goodyear, A.
A1 - Graves, J.
A1 - Tsalas, M.
A1 - Grist, D.
A1 - Jachmich, S.
A1 - Lang, P.
A1 - Lerche, E.
A1 - de la Luna, E.
A1 - Mooney, R.
A1 - Morris, J.
A1 - M F F Nave
A1 - Rimini, F.
A1 - Sips, G.
A1 - Solano, E.
A1 - JET-EFDA Contributors
AB - This paper describes the first development and implementation of a closed loop edge localized mode (ELM) frequency controller using gas injection as the actuator. The controller has been extensively used in recent experiments on JET and it has proved to work well at ELM frequencies in the 15–40 Hz range. The controller responds effectively to a variety of disturbances, generally recovering the requested ELM frequency within approximately 500 ms. Controlling the ELM frequency has become of prime importance in the new JET configuration with all metal walls, where insufficient ELM frequency is associated with excessive tungsten influx. The controller has allowed successful operation near the minimum acceptable ELM frequency where the best plasma confinement can be achieved. Use of the ELM frequency controller in conjunction with pellet injection has enabled investigations of ELM triggering by pellets while maintaining the desired ELM frequency even when pellets fail to trigger ELMs.
VL - 55
U1 - FP
U2 - PDG
U5 - 3bda42d1e65385a69f8f1e4ab2b8220b
ER -
TY - JOUR
T1 - Overview of MAST results
JF - Nuclear Fusion
Y1 - 2015
A1 - Chapman, I.T.
A1 - Adamek, J.
A1 - Akers, R. J.
A1 - Allan, S.
A1 - Appel, L.
A1 - Asunta, O.
A1 - Barnes, M.
A1 - N. Ben Ayed
A1 - Hawke, J.
A1 - Bigelow, T.
A1 - Boeglin, W.
A1 - Bradley, J.
A1 - Brünner, J.
A1 - Cahyna, P.
A1 - Carr, M.
A1 - Caughman, J.
A1 - Cecconello, M.
A1 - Challis, C.
A1 - Chapman, S.
A1 - Chorley, J.
A1 - Colyer, G.
A1 - Conway, N.
A1 - Cooper, W. A.
A1 - Cox, M.
A1 - Crocker, N.
A1 - Crowley, B.
A1 - Cunningham, G.
A1 - Danilov, A.
A1 - Darrow, D.
A1 - Dendy, R.
A1 - Diallo, A.
A1 - Dickinson, D.
A1 - Diem, S.
A1 - Dorland, W.
A1 - Dudson, B.
A1 - Dunai, D.
A1 - Easy, L.
A1 - Elmore, S.
A1 - Field, A.
A1 - Fishpool, G.
A1 - Fox, M.
A1 - Fredrickson, E.
A1 - Freethy, S.
A1 - Garzotti, L.
A1 - Ghim, Y. C.
A1 - Gibson, K.
A1 - Graves, J.
A1 - Gurl, C.
A1 - Guttenfelder, W.
A1 - Ham, C.
A1 - Harrison, J.
A1 - Harting, D.
A1 - Havlickova, E.
A1 - Hawkes, N.
A1 - Hender, T.
A1 - Henderson, S.
A1 - Highcock, E.
A1 - Hillesheim, J.
A1 - Hnat, B.
A1 - Holgate, J.
A1 - Horacek, J.
A1 - Howard, J.
A1 - Huang, B.
A1 - Imada, K.
A1 - Jones, O.
A1 - S. Kaye
A1 - Keeling, D.
A1 - Kirk, A.
A1 - Klimek, I.
A1 - Kocan, M.
A1 - Leggate, H.
A1 - Lilley, M.
A1 - Lipschultz, B.
A1 - Lisgo, S.
A1 - Liu, Y. Q.
A1 - Lloyd, B.
A1 - Lomanowski, B.
A1 - Lupelli, I.
A1 - Maddison, G.
A1 - J. Mailloux
A1 - Martin, R.
A1 - McArdle, G.
A1 - McClements, K.
A1 - McMillan, B.
A1 - Meakins, A.
A1 - Meyer, H.
A1 - Michael, C.
A1 - Militello, F.
A1 - Milnes, J.
A1 - Morris, A. W.
A1 - Motojima, G.
A1 - Muir, D.
A1 - Nardon, E.
A1 - Naulin, V.
A1 - Naylor, G.
A1 - Nielsen, A.
A1 - O'Brien, M.
A1 - O'Gorman, T.
A1 - Ono, Y.
A1 - Oliver, H.
A1 - Pamela, S.
A1 - Pangioni, L.
A1 - Parra, F.
A1 - Patel, A.
A1 - Peebles, W.
A1 - Peng, M.
A1 - Perez, R.
A1 - Pinches, S.
A1 - Piron, L.
A1 - Podesta, M.
A1 - Price, M.
A1 - Reinke, M.
A1 - Ren, Y.
A1 - Roach, C.
A1 - Robinson, J.
A1 - Romanelli, M.
A1 - Rozhansky, V.
A1 - Saarelma, S.
A1 - Sangaroon, S.
A1 - Saveliev, A.
A1 - Scannell, R.
A1 - Schekochihin, A.
A1 - Sharapov, S.
A1 - Sharples, R.
A1 - Shevchenko, V.
A1 - Silburn, S.
A1 - J. Simpson
A1 - Storrs, J.
A1 - Takase, Y.
A1 - Tanabe, H.
A1 - Tanaka, H.
A1 - Taylor, D.
A1 - Taylor, G.
A1 - Thomas, D.
A1 - Thomas-Davies, N.
A1 - Thornton, A.
A1 - Turnyanskiy, M.
A1 - Valovic, M.
A1 - Vann, R.
A1 - Walkden, N.
A1 - Wilson, H.
A1 - Wyk, L. V.
A1 - Yamada, T.
A1 - Zoletnik, S.
A1 - MAST Team
A1 - MAST Upgrade Teams
VL - 55
IS - 10
U1 - FP
U2 - TP
U5 - 9d7b191e90422e8ed8bcf2078b75987f
ER -