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1. Effects of Kinetic Ballooning Modes on the electron distribution function in the core of high-performance tokamak plasmas

Author

S. Mazzi, G. Giruzzi, Y. Camenen, R. Dumont, M. Fontana, E. de la Luna, F.P. Orsitto, L. Senni, K. Aleynikova, S. Brunner, B.J. Frei, J. Garcia, A. Zocco, D. Frigione, L. Garzotti, F. Rimini, D. van Eester, JET Contributors, and the EUROfusion Tokamak Exploitation Team

Subjects
Kinetic Ballooning modes, high-performance fusion plasmas, electron distribution function, discrepancy ECE-Thomson, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This article is dedicated to study the physical causes of a long-standing issue experienced in different tokamak devices throughout the last decades: the observed discrepancies between electron cyclotron emission (ECE) and Thomson Scattering (TS) diagnostic measurements at high temperature in the core tokamak plasmas. A recently developed heuristic model (Fontana et al 2023 Phys. Plasmas 30 122503), tested on an extensive data set from multiple pulses in the frame of recent JET campaigns, showed that such ECE-TS discrepancy could be reconciled by introducing a bipolar perturbation in the electron distribution function. Such a perturbation indeed modifies the EC emission and absorption spectra. Nonetheless, the heuristic model does not provide the physical mechanisms causing such a bipolar perturbation. In this work, detailed gyrokinetic analyses unveil the unexplored wave-particle interaction between electrons and the Kinetic Ballooning Modes (KBMs) in tokamak plasmas. The numerical studies of the core of a selected high-temperature pulse of the JET device revealed that the electron- β was large enough to destabilize KBMs. Such KBMs affect the electron distribution function in momentum space with a characteristic bipolar structure. The position of the bipolar structure in the velocity space is intimately linked to the electron diamagnetic frequency. The amplitude of the perturbation, assessed through nonlinear computations, is shown to be dependent on the amplitude of the KBM-induced turbulent fluxes. Thus, this study demonstrates that KBMs, destabilized by the high- β plasma conditions achieved in the core of high-temperature scenarios, perturb the electron distribution function forming bipolar structures in momentum space and, thereby, modifying the EC spectrum. Therefore, the reported mechanism may represent an intriguing explanation of the ECE-TS measurement discrepancy in the deep core of high-temperature plasmas.

Published
2024
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2. Overview of the EUROfusion Tokamak Exploitation programme in support of ITER and DEMO

Author

E. Joffrin, M. Wischmeier, M. Baruzzo, A. Hakola, A. Kappatou, D. Keeling, B. Labit, E. Tsitrone, N. Vianello, the ASDEX Upgrade Team, JET Contributors, the MAST-U Team, the TCV Team, the WEST Team, the EUROfusion Tokamak Exploitation Team:, D. Abate, J. Adamek, M. Agostini, C. Albert, F.C.P. Albert Devasagayam, S. Aleiferis, E. Alessi, J. Alhage, S. Allan, J. Allcock, M. Alonzo, G. Anastasiou, E. Andersson Sunden, C. Angioni, Y. Anquetin, L. Appel, G.M. Apruzzese, M. Ariola, C. Arnas, J.F. Artaud, W. Arter, O. Asztalos, L. Aucone, M.H. Aumeunier, F. Auriemma, J. Ayllon, E. Aymerich, A. Baciero, F. Bagnato, L. Bähner, F. Bairaktaris, P. Balázs, L. Balbinot, I. Balboa, M. Balden, A. Balestri, M. Baquero Ruiz, T. Barberis, C. Barcellona, O. Bardsley, S. Benkadda, T. Bensadon, E. Bernard, M. Bernert, H. Betar, R. Bianchetti Morales, J. Bielecki, R. Bilato, P. Bilkova, W. Bin, G. Birkenmeier, R. Bisson, P. Blanchard, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, K. Bogar, P. Bohm, T. Bolzonella, F. Bombarda, N. Bonanomi, L. Boncagni, D. Bonfiglio, R. Bonifetto, M. Bonotto, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, C. Bowman, S. Brezinsek, D. Brida, F. Brochard, R. Brunet, D. Brunetti, V. Bruno, R. Buchholz, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, J. Cai, R. Calado, J. Caloud, S. Cancelli, F. Cani, B. Cannas, M. Cappelli, S. Carcangiu, A. Cardinali, S. Carli, D. Carnevale, M. Carole, M. Carpita, D. Carralero, F. Caruggi, I.S. Carvalho, I. Casiraghi, A. Casolari, F.J. Casson, C. Castaldo, A. Cathey, F. Causa, J. Cavalier, M. Cavedon, J. Cazabonne, M. Cecconello, L. Ceelen, A. Celora, J. Cerovsky, C.D. Challis, R. Chandra, A. Chankin, B. Chapman, H. Chen, M. Chernyshova, A.G. Chiariello, P. Chmielewski, A. Chomiczewska, C. Cianfarani, G. Ciraolo, J. Citrin, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, I.H. Coffey, C. Colandrea, L. Colas, S. Conroy, C. Contre, N.J. Conway, L. Cordaro, Y. Corre, D. Costa, S. Costea, D. Coster, X. Courtois, C. Cowley, T. Craciunescu, G. Croci, A.M. Croitoru, K. Crombe, D.J. Cruz Zabala, G. Cseh, T. Czarski, A. Da Ros, A. Dal Molin, M. Dalla Rosa, Y. Damizia, O. D’Arcangelo, P. David, M. De Angeli, E. De la Cal, E. De La Luna, G. De Tommasi, J. Decker, R. Dejarnac, D. Del Sarto, G. Derks, C. Desgranges, P. Devynck, S. Di Genova, L.E. di Grazia, A. Di Siena, M. Dicorato, M. Diez, M. Dimitrova, T. Dittmar, L. Dittrich, J.J. Domínguez Palacios Durán, P. Donnel, D. Douai, S. Dowson, S. Doyle, M. Dreval, P. Drews, L. Dubus, R. Dumont, D. Dunai, M. Dunne, A. Durif, F. Durodie, G. Durr Legoupil Nicoud, B. Duval, R. Dux, T. Eich, A. Ekedahl, S. Elmore, G. Ericsson, J. Eriksson, B. Eriksson, F. Eriksson, S. Ertmer, A. Escarguel, B. Esposito, T. Estrada, E. Fable, M. Faitsch, N. Fakhrayi Mofrad, A. Fanni, T. Farley, M. Farník, N. Fedorczak, F. Felici, X. Feng, J. Ferreira, D. Ferreira, N. Ferron, O. Fevrier, O. Ficker, A.R. Field, A. Figueiredo, N. Fil, D. Fiorucci, M. Firdaouss, R. Fischer, M. Fitzgerald, M. Flebbe, M. Fontana, J. Fontdecaba Climent, A. Frank, E. Fransson, L. Frassinetti, D. Frigione, S. Futatani, R. Futtersack, S. Gabriellini, D. Gadariya, D. Galassi, K. Galazka, J. Galdon, S. Galeani, D. Gallart, A. Gallo, C. Galperti, M. Gambrioli, S. Garavaglia, J. Garcia, M. Garcia Munoz, J. Gardarein, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, M. Gelfusa, J. Gerardin, S.N. Gerasimov, R. Gerru Miguelanez, G. Gervasini, Z. Ghani, F.M. Ghezzi, G. Ghillardi, L. Giannone, S. Gibson, L. Gil, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, T. Gleiter, M. Gobbin, V. Goloborodko, A. González Ganzábal, T. Goodman, V. Gopakumar, G. Gorini, T. Görler, S. Gorno, G. Granucci, D. Greenhouse, G. Grenfell, M. Griener, W. Gromelski, M. Groth, O. Grover, M. Gruca, A. Gude, C. Guillemaut, R. Guirlet, J. Gunn, T. Gyergyek, L. Hagg, J. Hall, C.J. Ham, M. Hamed, T. Happel, G. Harrer, J. Harrison, D. Harting, N.C. Hawkes, P. Heinrich, S. Henderson, P. Hennequin, R. Henriques, S. Heuraux, J. Hidalgo Salaverri, J. Hillairet, J.C. Hillesheim, A. Hjalmarsson, A. Ho, J. Hobirk, E. Hodille, M. Hölzl, M. Hoppe, J. Horacek, N. Horsten, L. Horvath, M. Houry, K. Hromasova, J. Huang, Z. Huang, A. Huber, E. Huett, P. Huynh, A. Iantchenko, M. Imrisek, P. Innocente, C. Ionita Schrittwieser, H. Isliker, P. Ivanova, I. Ivanova Stanik, M. Jablczynska, S. Jachmich, A.S. Jacobsen, P. Jacquet, A. Jansen van Vuuren, A. Jardin, H. Järleblad, A. Järvinen, F. Jaulmes, T. Jensen, I. Jepu, S. Jessica, T. Johnson, A. Juven, J. Kalis, J. Karhunen, R. Karimov, A.N. Karpushov, S. Kasilov, Y. Kazakov, P.V. Kazantzidis, W. Kernbichler, HT. Kim, D.B. King, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, A. Kit, T. Kiviniemi, F. Kjær, E. Klinkby, A. Knieps, U. Knoche, M. Kochan, F. Köchl, G. Kocsis, J.T.W. Koenders, L. Kogan, Y. Kolesnichenko, Y. Kominis, M. Komm, M. Kong, B. Kool, S.B. Korsholm, D. Kos, M. Koubiti, J. Kovacic, Y. Kovtun, E. Kowalska Strzeciwilk, K. Koziol, M. Kozulia, A. Krämer Flecken, A. Kreter, K. Krieger, U. Kruezi, O. Krutkin, O. Kudlacek, U. Kumar, H. Kumpulainen, M.H. Kushoro, R. Kwiatkowski, M. La Matina, M. Lacquaniti, L. Laguardia, P. Lainer, P. Lang, M. Larsen, E. Laszynska, K.D. Lawson, A. Lazaros, E. Lazzaro, M.Y.K. Lee, S. Leerink, M. Lehnen, M. Lennholm, E. Lerche, Y. Liang, A. Lier, J. Likonen, O. Linder, B. Lipschultz, A. Listopad, X. Litaudon, E. Litherland Smith, D. Liuzza, T. Loarer, P.J. Lomas, J. Lombardo, N. Lonigro, R. Lorenzini, C. Lowry, T. Luda di Cortemiglia, A. Ludvig Osipov, T. Lunt, V. Lutsenko, E. Macusova, R. Mäenpää, P. Maget, C.F. Maggi, J. Mailloux, S. Makarov, K. Malinowski, P. Manas, A. Mancini, D. Mancini, P. Mantica, M. Mantsinen, J. Manyer, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, S. Marchioni, A. Mariani, M. Marin, M. Markl, T. Markovic, D. Marocco, S. Marsden, L. Martellucci, P. Martin, C. Martin, F. Martinelli, L. Martinelli, J.R. Martin Solis, R. Martone, M. Maslov, R. Masocco, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, M.L. Mayoral, D. Mazon, S. Mazzi, C. Mazzotta, G. McArdle, R. McDermott, K. McKay, A.G. Meigs, C. Meineri, A. Mele, V. Menkovski, S. Menmuir, A. Merle, H. Meyer, K. Mikszuta Michalik, D. Milanesio, F. Militello, A. Milocco, I.G. Miron, J. Mitchell, R. Mitteau, V. Mitterauer, J. Mlynar, V. Moiseenko, P. Molna, F. Mombelli, C. Monti, A. Montisci, J. Morales, P. Moreau, J.M. Moret, A. Moro, D. Moulton, P. Mulholland, M. Muraglia, A. Murari, A. Muraro, P. Muscente, D. Mykytchuk, F. Nabais, Y. Nakeva, F. Napoli, E. Nardon, M.F. Nave, R.D. Nem, A. Nielsen, S.K. Nielsen, M. Nocente, R. Nouailletas, S. Nowak, H. Nyström, R. Ochoukov, N. Offeddu, S. Olasz, C. Olde, F. Oliva, D. Oliveira, H.J.C. Oliver, P. Ollus, J. Ongena, F.P. Orsitto, N. Osborne, R. Otin, P. Oyola Dominguez, D.I. Palade, S. Palomba, O. Pan, N. Panadero, E. Panontin, A. Papadopoulos, P. Papagiannis, G. Papp, V.V. Parail, C. Pardanaud, J. Parisi, A. Parrott, K. Paschalidis, M. Passoni, F. Pastore, A. Patel, B. Patel, A. Pau, G. Pautasso, R. Pavlichenko, E. Pawelec, B. Pegourie, G. Pelka, E. Peluso, A. Perek, E. Perelli Cippo, C. Perez Von Thun, P. Petersson, G. Petravich, Y. Peysson, V. Piergotti, L. Pigatto, C. Piron, L. Piron, A. Pironti, F. Pisano, U. Plank, B. Ploeckl, V. Plyusnin, A. Podolnik, Y. Poels, G. Pokol, J. Poley, G. Por, M. Poradzinski, F. Porcelli, L. Porte, C. Possieri, A. Poulsen, I. Predebon, G. Pucella, M. Pueschel, P. Puglia, O. Putignano, T. Pütterich, V. Quadri, A. Quercia, M. Rabinski, L. Radovanovic, R. Ragona, H. Raj, M. Rasinski, J. Rasmussen, G. Ratta, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Refy, M. Reich, H. Reimerdes, B.C.G. Reman, O. Renders, C. Reux, D. Ricci, M. Richou, S. Rienacker, D. Rigamonti, F. Rigollet, F.G. Rimini, D. Ripamonti, N. Rispoli, N. Rivals, J.F. Rivero Rodriguez, C. Roach, G. Rocchi, S. Rode, P. Rodrigues, J. Romazanov, C.F. Romero Madrid, J. Rosato, R. Rossi, G. Rubino, J. Rueda Rueda, J. Ruiz Ruiz, P. Ryan, D. Ryan, S. Saarelma, R. Sabot, M. Salewski, A. Salmi, L. Sanchis, A. Sand, J. Santos, K. Särkimäki, M. Sassano, O. Sauter, G. Schettini, S. Schmuck, P. Schneider, N. Schoonheere, R. Schramm, R. Schrittwieser, C. Schuster, N. Schwarz, F. Sciortino, M. Scotto D’Abusco, S. Scully, A. Selce, L. Senni, M. Senstius, G. Sergienko, S.E. Sharapov, R. Sharma, A. Shaw, U. Sheikh, G. Sias, B. Sieglin, S.A. Silburn, C. Silva, A. Silva, D. Silvagni, B. Simmendefeldt Schmidt, L. Simons, J. Simpson, L. Singh, S. Sipilä, Y. Siusko, S. Smith, A. Snicker, E.R. Solano, V. Solokha, M. Sos, C. Sozzi, F. Spineanu, G. Spizzo, M. Spolaore, L. Spolladore, C. Srinivasan, A. Stagni, Z. Stancar, G. Stankunas, J. Stober, P. Strand, C.I. Stuart, F. Subba, G.Y. Sun, H.J. Sun, W. Suttrop, J. Svoboda, T. Szepesi, G. Szepesi, B. Tal, T. Tala, P. Tamain, G. Tardini, M. Tardocchi, D. Taylor, G. Telesca, A. Tenaglia, A. Terra, D. Terranova, D. Testa, C. Theiler, E. Tholerus, B. Thomas, E. Thoren, A. Thornton, A. Thrysoe, Q. TICHIT, W. Tierens, A. Titarenko, P. Tolias, E. Tomasina, M. Tomes, E. Tonello, A. Tookey, M. Toscano Jiménez, C. Tsironis, C. Tsui, A. Tykhyy, M. Ugoletti, M. Usoltseva, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, SI. Valvis, M. van Berkel, D. Van Eester, S. Van Mulders, M. van Rossem, R. Vann, B. Vanovac, J. Varela Rodriguez, J. Varje, S. Vartanian, M. Vecsei, L. Velarde Gallardo, M. Veranda, T. Verdier, G. Verdoolaege, K. Verhaegh, L. Vermare, G. Verona Rinati, J. Vicente, E. Viezzer, L. Vignitchouk, F. Villone, B. Vincent, P. Vincenzi, M.O. Vlad, G. Vogel, I. Voitsekhovitch, I. Voldiner, P. Vondracek, N.M.T. VU, T. Vuoriheimo, C. Wade, E. Wang, T. Wauters, M. Weiland, H. Weisen, N. Wendler, D. Weston, A. Widdowson, S. Wiesen, M. Wiesenberger, T. Wijkamp, M. Willensdorfer, T. Wilson, A. Wojenski, C. Wuethrich, I. Wyss, L. Xiang, S. Xu, D. Yadykin, Y. Yakovenko, H. Yang, V. Yanovskiy, R. Yi, B. Zaar, G. Zadvitskiy, L. Zakharov, P. Zanca, D. Zarzoso, Y. Zayachuk, J. Zebrowski, M. Zerbini, P. Zestanakis, C. F. B. Zimmermann, M. Zlobinski, A. Zohar, V.K. Zotta, X. Zou, M. Zuin, M. Zurita, and I. Zychor

Subjects
JET, ASDEX Upgrade, MAST-U, TCV, WEST, Tokamak Exploitation Task Force, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Within the 9th European Framework programme, since 2021 EUROfusion is operating five tokamaks under the auspices of a single Task Force called ‘Tokamak Exploitation’. The goal is to benefit from the complementary capabilities of each machine in a coordinated way and help in developing a scientific output scalable to future largre machines. The programme of this Task Force ensures that ASDEX Upgrade, MAST-U, TCV, WEST and JET (since 2022) work together to achieve the objectives of Missions 1 and 2 of the EUROfusion Roadmap: i) demonstrate plasma scenarios that increase the success margin of ITER and satisfy the requirements of DEMO and, ii) demonstrate an integrated approach that can handle the large power leaving ITER and DEMO plasmas. The Tokamak Exploitation task force has therefore organized experiments on these two missions with the goal to strengthen the physics and operational basis for the ITER baseline scenario and for exploiting the recent plasma exhaust enhancements in all four devices (PEX: Plasma EXhaust) for exploring the solution for handling heat and particle exhaust in ITER and develop the conceptual solutions for DEMO. The ITER Baseline scenario has been developed in a similar way in ASDEX Upgrade, TCV and JET. Key risks for ITER such as disruptions and run-aways have been also investigated in TCV, ASDEX Upgrade and JET. Experiments have explored successfully different divertor configurations (standard, super-X, snowflakes) in MAST-U and TCV and studied tungsten melting in WEST and ASDEX Upgrade. The input from the smaller devices to JET has also been proven successful to set-up novel control schemes on disruption avoidance and detachment.

Published
2024
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3. Overview of T and D–T results in JET with ITER-like wall

Author

C.F. Maggi, D. Abate, N. Abid, P. Abreu, O. Adabonyan, M. Afzal, I. Ahmad, M. Akhtar, R. Albanese, S. Aleiferis, E. Alessi, P. Aleynikov, J. Alguacil, J. Alhage, M. Ali, H. Allen, M. Allinson, M. Alonzo, E. Alves, R. Ambrosino, E. Andersson Sundén, P. Andrew, M. Angelone, C. Angioni, I. Antoniou, L. Appel, C. Appelbee, C. Aramunde, M. Ariola, G. Arnoux, G. Artaserse, J.-F. Artaud, W. Arter, V. Artigues, F.J. Artola, A. Ash, O. Asztalos, D. Auld, F. Auriemma, Y. Austin, L. Avotina, J. Ayllón, E. Aymerich, A. Baciero, L. Bähner, F. Bairaktaris, I. Balboa, M. Balden, N. Balshaw, V.K. Bandaru, J. Banks, A. Banon Navarro, C. Barcellona, O. Bardsley, M. Barnes, R. Barnsley, M. Baruzzo, M. Bassan, A. Batista, P. Batistoni, L. Baumane, B. Bauvir, L. Baylor, C. Bearcroft, P. Beaumont, D. Beckett, A. Begolli, M. Beidler, N. Bekris, M. Beldishevski, E. Belli, F. Belli, S. Benkadda, J. Bentley, E. Bernard, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, H. Betar, M. Beurskens, P.G. Bhat, S. Bickerton, J. Bielecki, T. Biewer, R. Bilato, P. Bílková, G. Birkenmeier, R. Bisson, J.P.S. Bizarro, P. Blatchford, A. Bleasdale, V. Bobkov, A. Boboc, A. Bock, G. Bodnar, P. Bohm, L. Bonalumi, N. Bonanomi, D. Bonfiglio, X. Bonnin, P. Bonofiglo, J. Booth, D. Borba, D. Borodin, I. Borodkina, T.O.S.J. Bosman, C. Bourdelle, M. Bowden, I. Božičević Mihalić, S.C. Bradnam, B. Breizman, S. Brezinsek, D. Brida, M. Brix, P. Brown, D. Brunetti, M. Buckley, J. Buermans, H. Bufferand, P. Buratti, A. Burckhart, A. Burgess, A. Buscarino, A. Busse, D. Butcher, G. Calabrò, L. Calacci, R. Calado, R. Canavan, B. Cannas, M. Cannon, M. Cappelli, S. Carcangiu, P. Card, A. Cardinali, S. Carli, P. Carman, D. Carnevale, B. Carvalho, I.S. Carvalho, P. Carvalho, I. Casiraghi, F.J. Casson, C. Castaldo, J.P. Catalan, N. Catarino, F. Causa, M. Cavedon, M. Cecconello, L. Ceelen, C.D. Challis, B. Chamberlain, R. Chandra, C.S. Chang, A. Chankin, B. Chapman, P. Chauhan, M. Chernyshova, A. Chiariello, G.-C. Chira, P. Chmielewski, A. Chomiczewska, L. Chone, J. Cieslik, G. Ciraolo, D. Ciric, J. Citrin, Ł. Ciupinski, R. Clarkson, M. Cleverly, P. Coates, V. Coccorese, R. Coelho, J.W. Coenen, I.H. Coffey, A. Colangeli, L. Colas, J. Collins, S. Conroy, C. Contré, N.J. Conway, D. Coombs, P. Cooper, S. Cooper, L. Cordaro, C. Corradino, Y. Corre, G. Corrigan, D. Coster, T. Craciunescu, S. Cramp, D. Craven, R. Craven, G. Croci, D. Croft, K. Crombé, T. Cronin, N. Cruz, A. Cufar, A. Cullen, A. Dal Molin, S. Dalley, P. David, A. Davies, J. Davies, S. Davies, G. Davis, K. Dawson, S. Dawson, I. Day, G. De Tommasi, J. Deane, M. Dearing, M. De Bock, J. Decker, R. Dejarnac, E. Delabie, E. de la Cal, E. de la Luna, D. Del Sarto, A. Dempsey, W. Deng, A. Dennett, G.L. Derks, G. De Temmerman, F. Devasagayam, P. de Vries, P. Devynck, A. di Siena, D. Dickinson, T. Dickson, M. Diez, P. Dinca, T. Dittmar, L. Dittrich, J. Dobrashian, T. Dochnal, A.J.H. Donné, W. Dorland, S. Dorling, S. Dormido-Canto, R. Dotse, D. Douai, S. Dowson, R. Doyle, M. Dreval, P. Drews, G. Drummond, Ph. Duckworth, H.G. Dudding, R. Dumont, P. Dumortier, D. Dunai, T. Dunatov, M. Dunne, I. Ďuran, F. Durodié, R. Dux, T. Eade, E. Eardley, J. Edwards, T. Eich, A. Eksaeva, H. El-Haroun, R.D. Ellis, G. Ellwood, C. Elsmore, S. Emery, G. Ericsson, B. Eriksson, F. Eriksson, J. Eriksson, L.G. Eriksson, S. Ertmer, G. Evans, S. Evans, E. Fable, D. Fagan, M. Faitsch, D. Fajardo Jimenez, M. Falessi, A. Fanni, T. Farmer, I. Farquhar, B. Faugeras, S. Fazinić, N. Fedorczak, K. Felker, R. Felton, H. Fernandes, D.R. Ferreira, J. Ferreira, G. Ferrò, J. Fessey, O. Février, O. Ficker, A.R. Field, A. Figueiredo, J. Figueiredo, A. Fil, N. Fil, P. Finburg, U. Fischer, G. Fishpool, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, S. Foley, N. Fonnesu, M. Fontana, J.M. Fontdecaba, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, C. Fowler, P. Fox, O. Franklin, E. Fransson, L. Frassinetti, R. Fresa, D. Frigione, T. Fülöp, M. Furseman, S. Gabriellini, D. Gadariya, S. Gadgil, K. Gál, S. Galeani, A. Galkowski, D. Gallart, M. Gambrioli, T. Gans, J. Garcia, M. García-Muñoz, L. Garzotti, J. Gaspar, R. Gatto, P. Gaudio, D. Gear, T. Gebhart, S. Gee, M. Gelfusa, R. George, S.N. Gerasimov, R. Gerru, G. Gervasini, M. Gethins, Z. Ghani, M. Gherendi, P.-I. Gherghina, F. Ghezzi, L. Giacomelli, C. Gibson, L. Gil, M.R. Gilbert, A. Gillgren, E. Giovannozzi, C. Giroud, G. Giruzzi, J. Goff, V. Goloborodko, R. Gomes, J.-F. Gomez, B. Gonçalves, M. Goniche, J. Gonzalez-Martin, A. Goodyear, S. Gore, G. Gorini, T. Görler, N. Gotts, E. Gow, J.P. Graves, J. Green, H. Greuner, E. Grigore, F. Griph, W. Gromelski, M. Groth, C. Grove, R. Grove, N. Gupta, S. Hacquin, L. Hägg, A. Hakola, M. Halitovs, J. Hall, C.J. Ham, M. Hamed, M.R. Hardman, Y. Haresawa, G. Harrer, J.R. Harrison, D. Harting, D.R. Hatch, T. Haupt, J. Hawes, N.C. Hawkes, J. Hawkins, S. Hazael, J. Hearmon, P. Heesterman, P. Heinrich, M. Held, W. Helou, O. Hemming, S.S. Henderson, R. Henriques, R.B. Henriques, D. Hepple, J. Herfindal, G. Hermon, J.C. Hillesheim, K. Hizanidis, A. Hjalmarsson, A. Ho, J. Hobirk, O. Hoenen, C. Hogben, A. Hollingsworth, S. Hollis, E. Hollmann, M. Hölzl, M. Hook, M. Hoppe, J. Horáček, N. Horsten, A. Horton, L.D. Horton, L. Horvath, S. Hotchin, Z. Hu, Z. Huang, E. Hubenov, A. Huber, V. Huber, T. Huddleston, G.T.A. Huijsmans, Y. Husain, P. Huynh, A. Hynes, D. Iglesias, M.V. Iliasova, M. Imríšek, J. Ingleby, P. Innocente, V. Ioannou-Sougleridis, N. Isernia, I. Ivanova-Stanik, E. Ivings, S. Jachmich, T. Jackson, A.S. Jacobsen, P. Jacquet, H. Järleblad, A. Järvinen, F. Jaulmes, N. Jayasekera, F. Jenko, I. Jepu, E. Joffrin, T. Johnson, J. Johnston, C. Jones, E. Jones, G. Jones, L. Jones, T.T.C. Jones, A. Joyce, M. Juvonen, A. Kallenbach, P. Kalnina, D. Kalupin, P. Kanth, A. Kantor, A. Kappatou, O. Kardaun, J. Karhunen, E. Karsakos, Ye.O. Kazakov, V. Kazantzidis, D.L. Keeling, W. Kelly, M. Kempenaars, D. Kennedy, K. Khan, E. Khilkevich, C. Kiefer, H.-T. Kim, J. Kim, S.H. Kim, D.B. King, D.J. Kinna, V.G. Kiptily, A. Kirjasuo, K.K. Kirov, A. Kirschner, T. Kiviniemi, G. Kizane, C. Klepper, A. Klix, G. Kneale, M. Knight, P. Knight, R. Knights, S. Knipe, U. Knoche, M. Knolker, M. Kocan, F. Köchl, G. Kocsis, J.T.W. Koenders, Y. Kolesnichenko, Y. Kominis, M. Kong, B. Kool, V. Korovin, S.B. Korsholm, B. Kos, D. Kos, M. Koubiti, Y. Kovtun, E. Kowalska-Strzęciwilk, K. Koziol, Y. Krasikov, A. Krasilnikov, V. Krasilnikov, M. Kresina, A. Kreter, K. Krieger, A. Krivska, U. Kruezi, I. Książek, H. Kumpulainen, B. Kurzan, S. Kwak, O.J. Kwon, B. Labit, M. Lacquaniti, A. Lagoyannis, L. Laguardia, A. Laing, V. Laksharam, N. Lam, H.T. Lambertz, B. Lane, M. Langley, E. Lascas Neto, E. Łaszyńska, K.D. Lawson, A. Lazaros, E. Lazzaro, G. Learoyd, C. Lee, K. Lee, S. Leerink, T. Leeson, X. Lefebvre, H.J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, F. Leipold, I. Lengar, M. Lennholm, E. Leon Gutierrez, L.A. Leppin, E. Lerche, A. Lescinskis, S. Lesnoj, L. Lewin, J. Lewis, J. Likonen, Ch. Linsmeier, X. Litaudon, E. Litherland-Smith, F. Liu, T. Loarer, A. Loarte, R. Lobel, B. Lomanowski, P.J. Lomas, J. Lombardo, R. Lorenzini, S. Loreti, V.P. Loschiavo, M. Loughlin, T. Lowe, C. Lowry, T. Luce, R. Lucock, T. Luda Di Cortemiglia, M. Lungaroni, C.P. Lungu, T. Lunt, V. Lutsenko, B. Lyons, J. Macdonald, E. Macusova, R. Mäenpää, H. Maier, J. Mailloux, S. Makarov, P. Manas, A. Manning, P. Mantica, M.J. Mantsinen, J. Manyer, A. Manzanares, Ph. Maquet, M. Maraschek, G. Marceca, G. Marcer, C. Marchetto, O. Marchuk, A. Mariani, G. Mariano, M. Marin, A. Marin Roldan, M. Marinelli, T. Markovič, L. Marot, C. Marren, S. Marsden, S. Marsen, J. Marsh, R. Marshall, L. Martellucci, A.J. Martin, C. Martin, R. Martone, S. Maruyama, M. Maslov, M. Mattei, G.F. Matthews, D. Matveev, E. Matveeva, A. Mauriya, F. Maviglia, M. Mayer, M.-L. Mayoral, S. Mazzi, C. Mazzotta, R. McAdams, P.J. McCarthy, P. McCullen, R. McDermott, D.C. McDonald, D. McGuckin, V. McKay, L. McNamee, A. McShee, D. Mederick, M. Medland, S. Medley, K. Meghani, A.G. Meigs, S. Meitner, S. Menmuir, K. Mergia, S. Mianowski, P. Middleton, J. Mietelski, K. Mikszuta-Michalik, D. Milanesio, E. Milani, E. Militello-Asp, F. Militello, J. Milnes, A. Milocco, S. Minucci, I. Miron, J. Mitchell, J. Mlynář, V. Moiseenko, P. Monaghan, I. Monakhov, A. Montisci, S. Moon, R. Mooney, S. Moradi, R.B. Morales, L. Morgan, F. Moro, J. Morris, T. Mrowetz, L. Msero, S. Munot, A. Muñoz-Perez, M. Muraglia, A. Murari, A. Muraro, B. N’Konga, Y.S. Na, F. Nabais, R. Naish, F. Napoli, E. Nardon, V. Naulin, M.F.F. Nave, R. Neu, S. Ng, M. Nicassio, D. Nicolai, A.H. Nielsen, S.K. Nielsen, D. Nina, C. Noble, C.R. Nobs, M. Nocente, H. Nordman, S. Nowak, H. Nyström, J. O’Callaghan, M. O’Mullane, C. O’Neill, C. Olde, H.J.C. Oliver, R. Olney, J. Ongena, G.P. Orsitto, A. Osipov, R. Otin, N. Pace, L.W. Packer, E. Pajuste, D. Palade, J. Palgrave, O. Pan, N. Panadero, T. Pandya, E. Panontin, A. Papadopoulos, G. Papadopoulos, G. Papp, V.V. Parail, A. Parsloe, K. Paschalidis, M. Passeri, A. Patel, A. Pau, G. Pautasso, R. Pavlichenko, A. Pavone, E. Pawelec, C. Paz-Soldan, A. Peacock, M. Pearce, I.J. Pearson, E. Peluso, C. Penot, K. Pepperell, A. Perdas, T. Pereira, E. Perelli Cippo, C. Perez von Thun, D. Perry, P. Petersson, G. Petravich, N. Petrella, M. Peyman, L. Pigatto, M. Pillon, S. Pinches, G. Pintsuk, C. Piron, A. Pironti, F. Pisano, R. Pitts, U. Planck, N. Platt, V. Plyusnin, M. Podesta, G. Pokol, F.M. Poli, O.G. Pompilian, M. Poradzinski, M. Porkolab, C. Porosnicu, G. Poulipoulis, A.S. Poulsen, I. Predebon, A. Previti, D. Primetzhofer, G. Provatas, G. Pucella, P. Puglia, K. Purahoo, O. Putignano, T. Pütterich, A. Quercia, G. Radulescu, V. Radulovic, R. Ragona, M. Rainford, P. Raj, M. Rasinski, D. Rasmussen, J. Rasmussen, J.J. Rasmussen, A. Raso, G. Rattá, S. Ratynskaia, R. Rayaprolu, M. Rebai, A. Redl, D. Rees, D. Réfy, R. Reichle, H. Reimerdes, B.C.G. Reman, C. Reux, S. Reynolds, D. Rigamonti, E. Righi, F.G. Rimini, J. Risner, J.F. Rivero-Rodriguez, C.M. Roach, J. Roberts, R. Robins, S. Robinson, D. Robson, S. Rode, P. Rodrigues, P. Rodriguez-Fernandez, S. Romanelli, J. Romazanov, E. Rose, C. Rose-Innes, R. Rossi, S. Rowe, D. Rowlands, C. Rowley, M. Rubel, G. Rubinacci, G. Rubino, M. Rud, J. Ruiz Ruiz, F. Ryter, S. Saarelma, A. Sahlberg, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, F. Sanchez, I. Sanders, D. Sandiford, F. Sanni, O. Sauter, P. Sauvan, G. Schettini, A. Shevelev, A.A. Schekochihin, K. Schmid, B.S. Schmidt, S. Schmuck, M. Schneider, P.A. Schneider, N. Schoonheere, R. Schramm, D. Scoon, S. Scully, M. Segato, J. Seidl, L. Senni, J. Seo, G. Sergienko, M. Sertoli, S.E. Sharapov, R. Sharma, A. Shaw, R. Shaw, H. Sheikh, U. Sheikh, N. Shi, P. Shigin, D. Shiraki, G. Sias, M. Siccinio, B. Sieglin, S.A. Silburn, A. Silva, C. Silva, J. Silva, D. Silvagni, D. Simfukwe, J. Simpson, P. Sirén, A. Sirinelli, H. Sjöstrand, N. Skinner, J. Slater, T. Smart, R.D. Smirnov, N. Smith, P. Smith, T. Smith, J. Snell, L. Snoj, E.R. Solano, V. Solokha, C. Sommariva, K. Soni, M. Sos, J. Sousa, C. Sozzi, T. Spelzini, F. Spineanu, L. Spolladore, D. Spong, C. Srinivasan, G. Staebler, A. Stagni, I. Stamatelatos, M.F. Stamp, Ž. Štancar, P.A. Staniec, G. Stankūnas, M. Stead, B. Stein-Lubrano, A. Stephen, J. Stephens, P. Stevenson, C. Steventon, M. Stojanov, D.A. St-Onge, P. Strand, S. Strikwerda, C.I. Stuart, S. Sturgeon, H.J. Sun, S. Surendran, W. Suttrop, J. Svensson, J. Svoboda, R. Sweeney, G. Szepesi, M. Szoke, T. Tadić, B. Tal, T. Tala, P. Tamain, K. Tanaka, W. Tang, G. Tardini, M. Tardocchi, D. Taylor, A.S. Teimane, G. Telesca, A. Teplukhina, A. Terra, D. Terranova, N. Terranova, D. Testa, B. Thomas, V.K. Thompson, A. Thorman, A.S. Thrysoe, W. Tierens, R.A. Tinguely, A. Tipton, H. Todd, M. Tomeš, A. Tookey, P. Tsavalas, D. Tskhakaya, L.-P. Turică, A. Turner, I. Turner, M. Turner, M.M. Turner, G. Tvalashvili, A. Tykhyy, S. Tyrrell, A. Uccello, V. Udintsev, A. Vadgama, D.F. Valcarcel, A. Valentini, M. Valisa, M. Vallar, M. Valovic, M. Van Berkel, K.L. van de Plassche, M. van Rossem, D. Van Eester, J. Varela, J. Varje, T. Vasilopoulou, G. Vayakis, M. Vecsei, J. Vega, M. Veis, P. Veis, S. Ventre, M. Veranda, G. Verdoolaege, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, E. Viezzer, L. Vignitchouk, R. Vila, R. Villari, F. Villone, P. Vincenzi, A. Vitins, Z. Vizvary, M. Vlad, I. Voldiner, U. Von Toussaint, P. Vondráček, B. Wakeling, M. Walker, R. Walker, M. Walsh, R. Walton, E. Wang, F. Warren, R. Warren, J. Waterhouse, C. Watts, T. Webster, M. Weiland, H. Weisen, M. Weiszflog, N. Wendler, A. West, M. Wheatley, S. Whetham, A. Whitehead, D. Whittaker, A. Widdowson, S. Wiesen, M. Willensdorfer, J. Williams, I. Wilson, T. Wilson, M. Wischmeier, A. Withycombe, D. Witts, A. Wojcik-Gargula, E. Wolfrum, R. Wood, R. Woodley, R. Worrall, I. Wyss, T. Xu, D. Yadykin, Y. Yakovenko, Y. Yang, V. Yanovskiy, R. Yi, I. Young, R. Young, B. Zaar, R.J. Zabolockis, L. Zakharov, P. Zanca, A. Zarins, D. Zarzoso Fernandez, K.-D. Zastrow, Y. Zayachuk, M. Zerbini, W. Zhang, B. Zimmermann, M. Zlobinski, A. Zocco, V.K. Zotta, M. Zuin, W. Zwingmann, and I. Zychor

Subjects
magnetic fusion, JET-ILW, D–T, tritium, alpha particles, fusion prediction, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

In 2021 JET exploited its unique capabilities to operate with T and D–T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D–T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements—new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors—as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D–T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D–T plasmas to date and expanding our understanding of isotopes and D–T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D–T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D–T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D–T operations is presented in (King et al Nucl. Fusion submitted).

Published
2024
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4. Fuelling of deuterium–tritium plasma by peripheral pellets in JET experiments

Author

M. Valovič, S. Aleiferis, P. Blatchford, A. Boboc, M. Brix, P. Carvalho, I. Carvalho, M. Fontdecaba Climent, D. Dunai, L. Frassinetti, L. Garzotti, F. Köchl, J.C. Lowry, E. de la Luna, C.F. Maggi, R.B. Morales, S. Nowak, C. Olde, D. Réfy, F. Rimini, S. Silburn, Ž. Štancar, G. Tvalashvili, M. Vecsei, and the JET Contributors

Subjects
tokamak, pellets, JET deuterium–tritium plasma, particle losses, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

A baseline scenario of deuterium–tritium (D–T) plasma with peripheral high-field-side fuelling pellets has been produced in JET in order to mimic the situation in ITER. The isotope mix ratio is controlled in order to target the value of 50%–50% by a combination of tritium gas puffing and deuterium pellet injection. Multiple factors controlling the fuelling efficiency of individual pellets are analysed, with the following findings: (1) prompt particle losses due to pellet-triggered edge-localised modes (ELMs) are detected, (2) the plasmoid drift velocity might be smaller than that predicted by simulation, (3) post-pellet particle loss is controlled by transient phases with ELMs.The overall pellet particle flux normalised to the heat flux is similar to that in previous pellet fuelling experiments in AUG and JET.

Published
2024
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5. Analysis of fusion alphas interaction with RF waves in D-T plasma at JET

Author

K.K. Kirov, F. Auriemma, P.J. Bonofiglo, C.D. Challis, E. De la Luna, J. Eriksson, D. Gallart, J. Garcia, M. Gorelenkova, J. Hobirk, P. Jacquet, A. Kappatou, Y. Kazakov, D. Keeling, D. King, V. Kiptily, E. Lerche, C. Maggi, J. Mailloux, P. Mantica, M. Mantsinen, M. Maslov, S. Menmuir, R. Sharma, P. Siren, Z. Stancar, D. Van Eester, and JET Contributors

Subjects
JET, DT plasma, alphas, synergistic effects, ICRH, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This work studies the influence of radio frequency (RF) waves in the ion cyclotron resonance heating (ICRH) range of frequencies on fusion alphas during the recent JET D-T campaign. Fusion alphas from D-T reactions are created with energies of about 3.5 MeV and therefore have significant Doppler shifts enabling synergistic interactions between them and RF waves at a broad range of frequencies, including the ones foreseen for future fusion machines in ITER (Schneider et al 2021 Nucl. Fusion 61 126058) and SPARC (Creely et al 2020 J. Plasma Phys. 86 865860502). Resonant interactions between RF waves and alphas, also called synergistic effects, will modify the alpha distribution and ultimately will have an impact on alpha orbit losses and heating. Data from JET 3.43 T/2.3 MA pulses based on the hybrid scenario (Hobirk et al 2023 Nucl. Fusion ; Hobirk et al 29th IAEA FEC23 Conf. ( 16–21 October 2023 ); Challis et al 48th EPS Conf. on Plasma Physics ( 27 June–1 July 2022 ) during the DTE2 campaign (Maggi et al 2023 Nucl. Fusion )) were used for the analysis in this study. The impact of synergistic effects on alpha orbit losses and alpha heating are assessed. The conclusions are based on the analysis of experimental data for fast alpha losses, i.e. measurements from neutral particle analyser (NPA), fast ion losses scintillator detector, Faraday cups (FCs), and TRANSP (Hawryluk et al 1980 Physics of Plasmas Close to Thermonuclear Conditions vol 1 (CEC) pp 19–46) simulations. Experimental data and TRANSP analysis indicates that there are indeed changes in the alpha distribution function (DF) due to interaction with RF waves. Data from the NPA show increased ^4 He flux in the range from a few hundred keV up to 800 keV for pulses with RF power, while TRANSP clearly shows modifications in the fast alpha DF for these energies. Data from the scintillator detector and the FCs were compared for pulses with and without ICRH power and versus cases with enhanced alpha losses due to MHD activity. The trends from these diagnostics consistently show no additional alpha losses due to interaction with RF waves. TRANSP predictions for the impact of ynergistic effects on alpha heating show up to a 42% increase in alpha electron heating and up to a 25% increase in alpha ion heating. These effects, however, become negligibly small, less than 1%, when alpha heating is compared to the total auxiliary heating power in the investigated JET pulses.

Published
2024
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6. Exploring the physics of a high-performance H-mode scenario with small ELMs at low collisionality in JET with Be/W wall

Author

E. de la Luna, J. Garcia, M. Sertoli, P. Lomas, S. Mazzi, Ž. Štancar, M. Dunne, N. Aiba, S. Silburn, M. Faitsch, G. Szepesi, F. Auriemma, I. Balboa, L. Frassinetti, L. Garzotti, S. Menmuir, D. Refy, F. Rimini, E.R. Solano, C. Sozzi, M. Vecsei, and JET Contributors

Subjects
fusion energy, tokamaks, plasma confinement, pedestal physics, gyrokinetic simulations, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

A new H-mode regime at low density and low edge safety factor ( q _95 = 3.2, with $I_\mathrm{p}$ = 3 MA) that combines high energy confinement, stationary conditions for density and radiation and small Edge Localized Modes (ELMs) have been found in JET with Be/W wall. Such a regime is achieved by operating without external gas puffing, leading to a decrease in the edge density and a substantial increase in rotation and ion temperature in both the pedestal and the core region. Transport modelling shows a reduction of the turbulence, which starts in the pedestal region and extends into the plasma core, and outward impurity convection, consistent with the improved energy confinement and the lack of W accumulation observed in those conditions. In addition, large type I ELMs, typically found in gas-fuelled plasmas, are replaced by smaller and more frequent ELMs, whose appearance is correlated with a substantial reduction of the pedestal density and its gradient. Pedestals in this operating regime are stable to peeling–ballooning modes, consistent with the lack of large ELMs. This is in contrast to results in unfuelled JET-C plasmas that typically operated at higher pedestal densities and developed low frequency, large type I ELMs, thus pointing to the low density as one of the critical parameters for accessing this small ELMs regime in JET. This small ELMs regime exhibits the same low pedestal collisionality ( $\nu_{\mathrm{e},\mathrm{ped}}^*\sim0.1$ ) expected in ITER and operates at low q _95 , thus making it different from other small ELMs regimes that are typically obtained at higher q _95 and higher pedestal collisionality. These features make this newly developed H-mode regime in JET with Be/W wall a valuable tool for exploring the underlying transport, the different mechanisms of turbulence stabilization, as well as the physics associated with the appearance of small ELMs in high-temperature plasmas at ITER relevant pedestal collisionality.

Published
2024
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7. Density profiles in stellarators: an overview of particle transport, fuelling and profile shaping studies at TJ-II

Author

J.A. Alonso, D. Alegre, J. Alonso, R. Antón, A. Arias-Camisón, E. Ascasíbar, A. Baciero, J.M. Barcala, M. Barnes, E. Blanco, L. Bueno, A. Bustos, S. Cabrera, E. de la Cal, I. Calvo, A. Cappa, D. Carralero, R. Carrasco, B. Carreras, R. Castro, A. de Castro, L. Cebrián, M. Chamorro, A.A. Chmyga, P. Colino, J. Duque, F.J. Escoto, T. Estrada, A. Fernández, J. Fraguas, J.M. Fontdecaba, A. Gabriel, L. García, I. García-Cortés, R. García-Gómez, J.M. García-Regaña, G. Godino-Sedano, J. Gómez-Manchón, A. González, A. González-Jerez, V. Guisse, J. Hernández-Sánchez, J. Hernanz, C. Hidalgo, P. Ivanova, A. Jiménez-Denche, D. Jiménez-Rey, G. Kocsis, M. Koepke, A.S. Kozachek, F. Lapayese, M. Liniers, D. López, D. López-Bruna, B. López-Miranda, E. de la Luna, E. Maragkoudakis, F. Martín-Díaz, G. Martín-Gómez, J. Martínez-Fernández, K.J. McCarthy, F. Medina, D. Medina-Roque, M. Medrano, P. Méndez, F.J. Miguel, B. van Milligen, A. Molinero, G. Motojima, S. Mulas, M. Navarro, I. Nedzelskiy, R. Nuñez, M. Ochando, E. Oyarzábal, J.L. de Pablos, F. Palomares, N. Panadero, F.I. Parra, C. Pastor, I. Pastor, A. de la Peña, R. Peralta, A. Pereira, P. Pons-Villalonga, A.B. Portas, E. Poveda, F.J. Ramos, G.A. Rattá, M. Redondo, C. Reynoso, E. Rincón, J. de la Riva, C. Rodríguez-Fernández, A. Ros, E. Sánchez, J. Sánchez, E. Sánchez-Sarabia, J.A. Sebastián, E.R. Solano, A. Soleto, T. Szepesi, F.L. Tabarés, D. Tafalla, H. Takahashi, N. Tamura, H. Thienpondt, A. Tolkachev, V. Tribaldos, R. Unamuno, J. Varela, J. Vega, J.L. Velasco, and I. Voldiner

Subjects
particle transport, fuelling, cryogenic pellet injection, stellarator, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

We provide an overview of activities carried out at the TJ-II stellarator for improving our understanding of- and developing plasma physics models for particle density profiles in stellarators. Namely, we report on recent progress in turbulent particle transport simulation, validation of pellet deposition models, density profile shaping for performance control and new experimental techniques for edge turbulence and plasma-neutral interaction.

Published
2024
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8. JET machine operations in T&D-T

Author

The JET Operations Team (presented by D.B. King), E. Abdelrahman, A. Abdul Hamid, N. Abid, K. Abraham, O. Adabonyan, C. Adlam, M. Afzal, M. Akhtar, V. Aldred, S. Aldworth, S. Aleiferis, M. Ali, R. Alie, R. Allan, H. Allen, E. Alli, M. Allinson, P. Almond, J. Angus, K. Antcliffe, I. Antoniou, L. Appel, C. Appelbee, C. Aramunde, N. Archer, S. Aria, H. Arkuszynski, M. Arshad, G. Artaserse, A. Ash, C. Ashe, T. Aue, D. Auld, B. Austin, Y. Austin, C. Ayres, R.B. Morales, S. Baker, S. Bakes, I. Balboa, C. Balshaw, N. Balshaw, J. Banks, J. Banner, A. Barnard, M. Barnard, M. Baruzzo, C. Basagiannis, S. Bathe Hariyanandan, P. Batistoni, R. Baughan, P. Beaumont, D. Beckett, A. Begolli, M. Beldishevski, K. Bell, E. Belonohy, J. Bentley, J. Bernardo, M. Berry, J. Bhatt, S. Bickerton, J. Bielecki, W. Bird, D. Blackett, K. Blackman, S. Blake, P. Blatchford, A. Bleasdale, A. Boboc, J. Booth, P. Boulting, M. Bowden, C. Boyd, K. Boyd, R. Bracey, D. Brennan, A. Brett, M. Bright, M. Brix, I. Brooks, B. Brown, P. Brown, M. Brown, P. Brummitt, B. Viola, A. Buckingham, M. Buckley, J. Bumpass, M. Burford, A. Burgess, J. Burton-Sweeten, A. Busse, D. Butcher, P. Cahill, P. Camp, I. Campbell, R. Canavan, J. Cane, M. Cannon, N. Canterbury, A. Carberry, P. Card, M. Carlick, M. Carlo, P. Carman, A. Carruthers, S. Carter, I.S. Carvalho, P. Carvalho, F. Casson, D. Chalk, B. Chamberlain, P. Chauhan, A. Chow, A. Churchman, D. Ciric, M. Clark, J. Clarkson, R. Clarkson, T. Clayton, M. Cleverly, P. Coates, I. Coffey, J. Collins, S. Conroy, N.J. Conway, R. Conway, J. Cook, M. Cooke, D. Coombs, P. Cooper, S. Cooper, G. Corrigan, R. Cotterell, A. Coulson, M. Cox, S. Cox, S. Cramp, D. Craven, R. Craven, M. Crick, D. Croft, T. Cronin, Z. Cui, A. Cullen, R. Cumming, C. Cummings, A. Dal Molin, P. Dalgliesh, S. Dalley, A. Danquah, S. Davies, G. Davis, H. Dawson, K. Dawson, S. Dawson, I. Day, L. de Caires, E. de la Luna, K. Deakin, J. Deane, M. Dearing, A. Dennett, T. Dickson, J. Dobrashian, T. Dochnal, S. Dorling, D. Douai, S. Dowson, J. Drewitt, G. Drummond, P. Dumortier, R. Eade, R. Eastham, K. Eden, J. Edmond, J. Edwards, P. Edwards, H. Elamin, S. Elford, H. El-Haroun, P. Ellis, C. Elsmore, S. Emery, G. Evans, S. Evans, D. Fagan, T. Farmer, I. Farquhar, R. Felton, F. Ferner, J. Fessey, P. Finburg, G. Fishpool, L. Fittill, J. Flanagan, K. Flinders, S. Foley, M. Fontana, M. Fortune, J. Foster, C. Fowler, P. Fox, O. Franklin, R. Franklin, R. Fraser, S. French, M. Furseman, A. Gabbidon, L. Garcia, J. Garcia, M. Gardener, D. Gear, T. Gedling, S. Gee, P. Gell, R. George, S. Gerasimov, M. Gethins, Z. Ghani, L. Giacomelli, C. Gibson, V. Gilsenan, C. Giroud, R. Glen, J. Goff, C. Goodman, A. Goodyear, A. Gordon, S. Gore, S. Gosden, N. Gotts, E. Gow, W. Graham, G. Graham, M. Green, R. Gregory, R. Griffiths, T. Griffiths, F. Griph, C. Grundy, T. Grundy, D. Guard, D. Guest, C. Gurl, S. Hacquin, A. Hakola, K. Hammond, H. Harmer, P. Harper, S. Harris, D. Hart, D. Hattan, A. Haupt, J. Hawes, N. Hawkes, J. Hawkins, P. Hawkins, S. Hayes, S. Hazael, D. Heads, P. Heesterman, O. Hemming, R.B. Henriques, G. Hermon, G. Hewson, T. Hibberd, M. Hill, J. Hillesheim, I. Hirb, K. Ho, C. Hogben, A. Hollingsworth, S. Hollis, M. Hook, D. Hopley, N. Horsten, A. Horton, L.D. Horton, L. Horvath, S. Hotchin, Z. Huang, E. Hubenov, V. Huber, A. Huber, C. Huddart, T. Huddleston, T. Hunter, Y. Husain, A. Hynes, J. Ingleby, S. Ives, E. Ivings, S. Jackson, T. Jackson, P. Jacquet, N. Jayasekera, I. Jepu, D. Jezzard, E. Joffrin, R. Johnson, J. Johnston, C. Jones, E. Jones, G. Jones, L. Jones, S. Jones, T. Jones, M. Jones, A. Joyce, M. Juvonen, A. Kantor, A. Kappatou, G. Karajgikar, J. Karhunen, I. Karnowska-Paterski, E. Karsakos, G. Kaveney, G. Kay, D. Keeling, T. Keenan, R. Kelly, W. Kelly, D. Kennedy, R. Kennedy, O. Kent, K. Khan, D. King, D. Kinna, V. Kiptily, K. Kirov, G. Kneale, M. Knight, P. Knight, J. Knipe, R. Knipe, S. Knipe, P. Kochanski, D. Kos, M. Kovari, E. Kowalska-Strzęciwilk, N. Kraus, M. Kresina, B. Labit, A. Laing, V. Laksharam, N. Lam, B. Lane, C. Lane, T. Lavender, A. Lawson, K. Lawson, G. Learoyd, T. Leeson, X. Lefebvre, J. Lehmann, M. Lennholm, K. Lennon, E. Lerche, S. Lesnoj, E. Letellier, L. Lewin, J. Lewis, J. Li, G. Liddiard, E. Litherland-Smith, F. Liu, R. Lobel, J. Logan, P. Lomas, C. Long, U. Losada, C. Loveridge, T. Lowe, C. Lowry, R. Lucock, G. Lyons, J. Macdonald, P. Macheta, T. Madden, J. Maddock, C.F. Maggi, J. Mailloux, A. Manning, C. Manning, N. Mantel, A. Manzanares, S. Marsden, J. Marsh, R. Marshall, A. Martin, M. Maslov, G. Matthews, N. Mayfield, M. Mayoral, R. McAdams, L. McCafferty, P. McCullen, D. McDonald, A. McDonnell, D. McGuckin, T. McIver, V. McKay, R. McKean, L. McNamee, A. McShee, R. Meadows, D. Mederick, M. Medland, K. Meghani, A. Meigs, S. Menmuir, I. Merrigan, S. Mianowski, P. Middleton, C. Miles, J. Milnes, A. Milocco, J. Mitchell, P. Mitchell, P. Monaghan, I. Monakhov, P. Moody, R. Mooney, C. Moore, N. Mooring, L. Morgan, R. Morgan, J. Morris, O. Morton, S. Morton, P. Mulvana, S. Munot, R. Munro-Smith, K. Musgrave, R. Naish, N. Neethiraj, J. Neilson, A. Newman, S. Ng, M. Nicassio, K. Nicholls, M. Nightingale, C. Noble, R. Normington, C. Nygaard, J. O’Callaghan, R. Olney, B. O’Meara, M. O’Mullane, C. O’Neill, C. Opara, K. O’Rourke, J. Ottley, K. Otu, A. Owen, N. Pace, K. Palamartchouk, D. Paley, J. Palgrave, G. Papadopoulos, V. Parail, A. Parrott, A. Parsloe, L. Parsons, R. Parsons, A. Patel, J. Patel, A. Peacock, M. Pearce, T. Pearce, I. Pearson, J. Penzo, A. Perdas, T. Pereira, C. Perez Von Thun, D. Perry, N. Petrella, M. Peyman, N. Platt, M. Poradzinski, M. Porter, M. Porton, C. Powell, J. Pozzi, M. Price, L. Price, P. Puglia, D. Pulley, K. Purahoo, M. Rainford, A. Raj, S. Randhawa, S. Rapa, K. Ravisankar, C. Rayner, A. Read, C. Reux, S. Reynolds, V. Riccardo, L. Richiusa, D. Rigamonti, F. Rimini, J. Roberts, R. Robins, S. Robinson, T. Robinson, D. Robson, S. Romanelli, F. Rose, C. Rose-Innes, D. Rouse, S. Rowe, N. Rowland, D. Rowlands, M. Rubel, K. Sabin, R. Salmon, H. Salter, A. Sanders, E. Sanders, I. Sanders, D. Sandiford, F. Sanni, R. Sarwar, R. Sayles, C. Scaysbrook, G. Scott, D. Scraggs, S. Scully, R. Sealey, E. Searle, M. Segato, M. Sertoli, C. Shanks, R. Sharma, A. Shaw, K. Sheahan, H. Sheikh, D. Shrestha, R. Siddiqui, S. Silburn, J. Silva, D. Simfukwe, J. Simpson, M. Sinclair, A. Sips, P. Sirén, S. Skeats, N. Skinner, B. Slade, J. Slater, T. Smart, G. Smith, J. Smith, N. Smith, P. Smith, T. Smith, F. P. Smith, J. Snell, K. Snelling, K. Soare, E. Solano, A. Spelzini, C. Srinivasan, Z. Stancar, P.A. Staniec, M. Stead, R. Steadman, L. Steel, D. Steele, A. Stephen, J. Stephens, L. Stevenson, P. Stevenson, C. Steventon, L. Sticklen, M. Stojanov, S. Strikwerda, C. Stuart, G. Stubbs, N. Studd, W. Studholme, H. Sun, S. Surendran, G. Szepesi, M. Szoke, H. Tan, A. Taylor, D. Taylor, K. Taylor, A. Thingore, B. Thomas, J. Thomas, A. Thorman, A. Tilley, A. Tipton, N. Tipton, H. Todd, P. Tonner, A. Tookey, M. Towndrow, M. Tsang, E. Tsitrone, I. Turner, M. Turner, G. Tvalashvili, S. Tyrrell, A. Vadgama, D. Valcarcel, Q. Van Der Westhuizen, J. Verdon, N. Vianello, A. Vittal, Z. Vizvary, B. Wakeling, M. Walker, R. Walker, T. Wall, M. Walsh, T. Walsh, J. Walters, J. Walton, R. Walton, S. Warder, F. Warren, R. Warren, J. Waterhouse, T. Webster, G. Wells, C. Wellstood, A. West, M. Wheatley, S. Whiffin, A. Whitehead, C. Whitehead, D. Whittaker, A. Widdowson, J. Wilcox, D. Wilkins, R. Wilkins, J. Williams, M. Williams, D. Willoughby, A. Wilson, I. Wilson, T. Wilson, M. Wischmeier, P. Wise, G. Withenshaw, A. Withycombe, D. Witts, J. Witts, R. Wood, L. Woodham, C. Woodley, J. Woodley, R. Woodley, B. Woods, S. Wray, T. Xu, I. Young, R. Young, K-D. Zastrow, Y. Zayachuk, and M. Zerbini

Subjects
JET, tritium, operations, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

JET, the world’s largest operating tokamak with unique Be/W wall and tritium handling capability, completed a Deuterium-Tritium (D-T) campaign in 2021 (Maggi et al 29th Fusion Energy Conf. ) following a decade of preparatory experiments, dedicated enhancements, technical rehearsals and training (Horton et al 2016 Fusion Eng. Des. 109–111 925). Operation with tritium raises significant technical, safety and scientific challenges not encountered in standard protium or deuterium operation. This contribution describes the tritium operational requirements, pulses and technical preparations, new operating procedures, lessons learned and details on the achieved operational availability and performance. The preparation and execution of the recent JET tritium experiments benefitted from the previous experience in 1991 (Preliminary Tritium Experiment), 1997 (DTE1 campaign) and 2003 (Trace Tritium Campaigns) and consisted of the following five phases: technical rehearsals and scenario preparation, tritium commissioning, 100% tritium campaign, D-T campaign (DTE2), tritium clean-up. Following the clean-up JET resumed normal operation and is currently undertaking a further D-T campaign (DTE3).

Published
2024
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9. The core–edge integrated neon-seeded scenario in deuterium–tritium at JET

Author

C. Giroud, I.S. Carvalho, S. Brezinsek, A. Huber, D. Keeling, J. Mailloux, R.A. Pitts, E. Lerche, R. Henriques, J. Hillesheim, K. Lawson, M. Marin, E. Pawelec, M. Sos, H.J. Sun, M. Tomes, S. Aleiferis, A. Bleasdale, M. Brix, A. Boboc, J. Bernardo, P. Carvalho, I. Coffey, S. Henderson, D.B. King, F. Rimini, M. Maslov, E. Alessi, T. Craciunescu, M. Fontana, J.M. Fontdecaba, L. Garzotti, Z. Ghani, L. Horvath, I. Jepu, J. Karhunen, D. Kos, E. Litherland-Smith, A. Meigs, S. Menmuir, R.B. Morales, S. Nowak, E. Peluso, T. Pereira, V. Parail, G. Petravich, G. Pucella, P. Puglia, D. Refy, S. Scully, M. Sertoli, S. Silburn, D. Taylor, B. Thomas, A. Tookey, Ž. Štancar, G. Szepesi, B. Viola, A. Widdowson, E. de la Luna, and JET Contributors

Subjects
JET, baseline, deuterium–tritium, detachment, neon, seeding, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This paper reports the first experiment carried out in deuterium–tritium addressing the integration of a radiative divertor for heat-load control with good confinement. Neon seeding was carried out for the first time in a D–T plasma as part of the second D–T campaign of JET with its Be/W wall environment. The technical difficulties linked to the re-ionisation heat load are reported in T and D–T. This paper compares the impact of neon seeding on D–T plasmas and their D counterpart on the divertor detachment, localisation of the radiation, scrape-off profiles, pedestal structure, edge localised modes and global confinement.

Published
2024
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10. Characterisation of divertor detachment onset in JET-ILW hydrogen, deuterium, tritium and deuterium–tritium low-confinement mode plasmas

Author

M. Groth, V. Solokha, S. Aleiferis, S. Brezinsek, M. Brix, I.S. Carvalho, P. Carvalho, G. Corrigan, D. Harting, N. Horsten, I. Jepu, J. Karhunen, K. Kirov, B. Lomanowski, K.D. Lawson, C. Lowry, A.G. Meigs, S. Menmuir, E. Pawelec, T. Pereira, A. Shaw, S. Silburn, B. Thomas, S. Wiesen, P. Börner, D. Borodin, S. Jachmich, D. Reiter, G. Sergienko, Z. Stancar, B. Viola, P. Beaumont, J. Bernardo, I. Coffey, N.J. Conway, E. de la Luna, D. Douai, C. Giroud, J. Hillesheim, L. Horvath, A. Huber, P. Lomas, C.F. Maggi, M. Maslov, C. Perez von Thun, S. Scully, N. Vianello, and M. Wischmeier

Subjects
Detachment, Hydrogen isotopes, JET, Nuclear engineering. Atomic power, TK9001-9401
Abstract

Measurements of the ion currents to and plasma conditions at the low-field side (LFS) divertor target plate in low-confinement mode plasmas in the JET ITER-like wall materials configuration show that the core plasma density required to detach the LFS divertor plasma is independent of the hydrogenic species protium, deuterium and tritium, and a 40 %/60 % deuterium–tritium mixture. This observation applies to a divertor plasma configuration with the LFS strike line connected to the horizontal part of the LFS divertor chosen because of its superior diagnostic coverage. The finding is independent of the operational status of the JET cryogenic pump. The electron temperature (Te) at the LFS strike line was markedly reduced from 25 eV to 5 eV over a narrow range of increasing core plasma density, and observed to be between 2 eV and 3 eV at the onset of detachment. The electron density (ne) peaks across the LFS plasma when Te at the target plate is 1 eV, and spatially moves to the X-point for higher core densities. The density limit was found approximately 20 % higher in protium than in tritium and deuterium–tritium plasmas.

Published
2023
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11. The JET hybrid scenario in Deuterium, Tritium and Deuterium-Tritium

Author

J. Hobirk, C.D. Challis, A. Kappatou, E. Lerche, D. Keeling, D. King, S. Aleiferis, E. Alessi, C. Angioni, F. Auriemma, M. Baruzzo, É. Belonohy, J. Bernardo, A. Boboc, I.S. Carvalho, P. Carvalho, F.J. Casson, A. Chomiczewska, J. Citrin, I.H. Coffey, N.J. Conway, D. Douai, E. Delabie, B. Eriksson, J. Eriksson, O. Ficker, A.R. Field, M. Fontana, J.M. Fontdecaba, L. Frassinetti, D. Frigione, D. Gallart, J. Garcia, M. Gelfusa, Z. Ghani, L. Giacomelli, E. Giovannozzi, C. Giroud, M. Goniche, W. Gromelski, S. Hacquin, C. Ham, N.C. Hawkes, R.B. Henriques, J.C. Hillesheim, A. Ho, L. Horvath, I. Ivanova-Stanik, P. Jacquet, F. Jaulmes, E. Joffrin, H.T. Kim, V. Kiptily, K. Kirov, D. Kos, E. Kowalska-Strzeciwilk, H. Kumpulainen, K. Lawson, M. Lennholm, X. Litaudon, E. Litherland-Smith, P.J. Lomas, E. de la Luna, C.F. Maggi, J. Mailloux, M.J. Mantsinen, M. Maslov, G. Matthews, K.G. McClements, A.G. Meigs, S. Menmuir, A. Milocco, I.G. Miron, S. Moradi, R.B. Morales, S. Nowak, F. Orsitto, A. Patel, L. Piron, C. Prince, G. Pucella, E. Peluso, C. Perez von Thun, E. Rachlew, C. Reux, F. Rimini, S. Saarelma, P. A Schneider, S. Scully, M. Sertoli, S. Sharapov, A. Shaw, S. Silburn, A. Sips, P. Siren, C. Sozzi, E.R. Solano, Z. Stancar, G. Stankunas, C. Stuart, H.J. Sun, G. Szepesi, D. Valcarcel, M. Valisa, G. Verdoolaege, B. Viola, N. Wendler, M. Zerbini, and JET Contributors

Subjects
magnetic fusion, hybrid scenario, Tritium, D-T, isotope effects, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The JET hybrid scenario has been developed from low plasma current carbon wall discharges to the record-breaking Deuterium-Tritium plasmas obtained in 2021 with the ITER-like Be/W wall. The development started in pure Deuterium with refinement of the plasma current, and toroidal magnetic field choices and succeeded in solving the heat load challenges arising from 37 MW of injected power in the ITER like wall environment, keeping the radiation in the edge and core controlled, avoiding MHD instabilities and reaching high neutron rates. The Deuterium hybrid plasmas have been re-run in Tritium and methods have been found to keep the radiation controlled but not at high fusion performance probably due to time constraints. For the first time this scenario has been run in Deuterium-Tritium (50:50). These plasmas were re-optimised to have a radiation-stable H-mode entry phase, good impurity control through edge T _i gradient screening and optimised performance with fusion power exceeding 10 MW for longer than three alpha particle slow down times, 8.3 MW averaged over 5 s and fusion energy of 45.8 MJ.

Published
2023
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12. Divertor power load investigations with deuterium and tritium in type-I ELMy H-mode plasmas in JET with the ITER-like wall

Author

M. Faitsch, I. Balboa, P. Lomas, S.A. Silburn, A. Tookey, D. Kos, A. Huber, E. de la Luna, D. Keeling, A. Kappatou, and JET Contributors

Subjects
tritium, power exhaust, type-I ELMs, power fall-off length, tokamak, JET, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Divertor power load is a major challenge towards a burning plasma in a next-step tokamak. Here, the first results of a divertor power load characterisation in tritium plasmas in type-I ELMy H-mode, obtained in the JET deuterium-tritium campaign (DTE2) performed in 2021, are presented. It is demonstrated that both, transient loads due to type-I ELMs as well as the power fall-off length, do not exhibit an explicit ion mass dependence, with remarkably similar values in the tritium plasmas and in the deuterium references. This gives an improved credence to published scaling law predictions, solely based on deuterium plasma experiments. Moreover, the type-I ELM impact on the inner divertor target is studied in deuterium discharges. A slightly increased parallel energy fluence on the inner target with a factor of 1.08 compared to the outer target is observed. This is explained by the smaller major radius of the inner target.

Published
2023
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13. JET D-T scenario with optimized non-thermal fusion

Author

M. Maslov, E. Lerche, F. Auriemma, E. Belli, C. Bourdelle, C.D. Challis, A. Chomiczewska, A. Dal Molin, J. Eriksson, J. Garcia, J. Hobirk, I. Ivanova-Stanik, Ph. Jacquet, A. Kappatou, Y. Kazakov, D.L. Keeling, D.B. King, V. Kiptily, K. Kirov, D. Kos, R. Lorenzini, E. De La Luna, C.F. Maggi, J. Mailloux, P. Mantica, M. Marin, G. Matthews, I. Monakhov, M. Nocente, G. Pucella, D. Rigamonti, F. Rimini, S. Saarelma, M. Salewski, E.R. Solano, Ž. Štancar, G. Stankunas, H. Sun, M. Tardocchi, D. Van Eester, and JET Contributors

Subjects
tokamak, nuclear fusion, tritium, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

In JET deuterium-tritium (D-T) plasmas, the fusion power is produced through thermonuclear reactions and reactions between thermal ions and fast particles generated by neutral beam injection (NBI) heating or accelerated by electromagnetic wave heating in the ion cyclotron range of frequencies (ICRFs). To complement the experiments with 50/50 D/T mixtures maximizing thermonuclear reactivity, a scenario with dominant non-thermal reactivity has been developed and successfully demonstrated during the second JET deuterium-tritium campaign DTE2, as it was predicted to generate the highest fusion power in JET with a Be/W wall. It was performed in a 15/85 D/T mixture with pure D-NBI heating combined with ICRF heating at the fundamental deuterium resonance. In steady plasma conditions, a record 59 MJ of fusion energy has been achieved in a single pulse, of which 50.5 MJ were produced in a 5 s time window ( P _fus = 10.1 MW) with average Q = 0.33, confirming predictive modelling in preparation of the experiment. The highest fusion power in these experiments, P _fus = 12.5 MW with average Q = 0.38, was achieved over a shorter 2 s time window, with the period of sustainment limited by high-Z impurity accumulation. This scenario provides unique data for the validation of physics-based models used to predict D-T fusion power.

Published
2023
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14. Experiments in high-performance JET plasmas in preparation of second harmonic ICRF heating of tritium in ITER

Author

M.J. Mantsinen, P. Jacquet, E. Lerche, D. Gallart, K. Kirov, P. Mantica, D. Taylor, D. Van Eester, M. Baruzzo, I. Carvalho, C.D. Challis, A. Dal Molin, E. Delabie, E. De La Luna, R. Dumont, P. Dumortier, J. Eriksson, D. Frigione, J. Garcia, L. Garzotti, C. Giroud, R. Henriques, J. Hobirk, A. Kappatou, Y. Kazakov, D. Keeling, D. King, V. Kiptily, M. Lennholm, P. Lomas, C. Lowry, C.F. Maggi, J. Mailloux, M. Maslov, S. Menmuir, I. Monakhov, R.B. Morales, C. Noble, M. Nocente, A. Patel, G. Pucella, C. Reux, D. Rigamonti, F. Rimini, A. Sheikh, S. Silburn, P. Siren, E.R. Solano, Z. Stancar, M. Tardocchi, and JET Contributors

Subjects
ICRF heating, fast ions, computational modelling, JET tokamak, H-mode hybrid plasma scenario, deuterium–tritium fuel mixture, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The reference ion cyclotron resonance frequency (ICRF) heating schemes for ITER deuterium–tritium (D-T) plasmas at the full magnetic field of 5.3 T are second harmonic heating of T and ^3 He minority heating. The wave-particle resonance location for these schemes coincide and are central at a wave frequency of 53 MHz at 5.3 T. Experiments have been carried out in the second major D-T campaign (DTE2) at JET, and in its prior D campaigns, to integrate these ICRF scenarios in JET high-performance plasmas and to compare their performance with the commonly used hydrogen (H) minority heating. In 50:50 D:T plasmas, up to 35% and 5% larger fusion power and diamagnetic energy content, respectively, were obtained with second harmonic heating of T as compared to H minority heating at comparable total input powers and gas injection rates. The core ion temperature was up to 30% and 20% higher with second harmonic T and ^3 He minority heating, respectively, with respect to H minority heating. These are favourable results for the use of these scenarios in ITER and future fusion reactors. According to modelling, adding ICRF heating to neutral beam injection using D and T beams resulted in a 10%–20% increase of on-axis bulk ion heating in the D-T plasmas due to its localisation in the plasma core. Central power deposition was confirmed with the break-in-slope and fast Fourier transform analysis of ion and electron temperature in response to ICRF modulation. The tail temperature of fast ICRF-accelerated tritons, their enhancement of the fusion yield and time behaviour as measured by an upgraded magnetic proton recoil spectrometer and neutral particle analyser were found in agreement with theoretical predictions. No losses of ICRF-accelerated ions were observed by fast ion detectors, which was as expected given the high plasma density of n _e ≈ 7–8 × 10 ^19 m ^−3 in the main heating phase that limited the formation of ICRF-accelerated fast ion tails. ^3 He was introduced in the machine by ^3 He gas injection, and the ^3 He concentration was measured by a high-resolution optical penning gauge in the sub-divertor region. The DTE2 experiments with ^3 He minority heating were carried with a low ^3 He concentration in the range of 2%–4% given the fact that the highest neutron rates with ^3 He minority heating in D plasmas were obtained at low ^3 He concentrations of ∼2%, which also coincided with the highest plasma diamagnetic energy content. In addition to ^3 He introduced by ^3 He gas injection, an intrinsic concentration of ^3 He of the order of 0.2%–0.4% was measured in D-T plasmas before ^3 He was introduced in the device, which is attributed to the radioactive decay of tritium to ^3 He. According to modelling, even such low intrinsic concentrations of ^3 He lead to significant changes in ICRF power partitioning during second harmonic heating of T due to absorption of up to 30% of the wave power by ^3 He.

Published
2023
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15. L-H transition studies in tritium and deuterium–tritium campaigns at JET with Be wall and W divertor

Author

E.R. Solano, G. Birkenmeier, C. Silva, E. Delabie, J.C. Hillesheim, A. Baciero, I. Balboa, M. Baruzzo, A. Boboc, M. Brix, J. Bernardo, C. Bourdelle, I.S. Carvalho, P. Carvalho, C.D. Challis, M. Chernyshova, A. Chomiczewska, R. Coelho, I. Coffey, T. Craciunescu, E. de la Cal, E. de la Luna, R. Dumont, P. Dumortier, M. Fontana, J.M. Fontdecaba, L. Frassinetti, D. Gallart, J. Garcia, C. Giroud, W. Gromelski, R.B. Henriques, J. Hall, A. Ho, L.D. Horton, L. Horvath, P. Jacquet, I. Jepu, E. Joffrin, A. Kappatou, D.L. Keeling, D.B. King, V.G. Kiptily, K.K. Kirov, D. Kos, E. Kowalska-Strzęciwilk, M. Lennholm, E. Lerche, E. Litherland-Smith, A. Loarte, B. Lomanowski, P.J. Lomas, C.F. Maggi, J. Mailloux, M.J. Mantsinen, M. Maslov, A.G. Meigs, I. Monakhov, R.B. Morales, A.H. Nielsen, D. Nina, C. Noble, E. Pawelec, M. Poradzinski, G. Pucella, P. Puglia, D. Réfy, J. Juul Rasmussen, E. Righi, F.G. Rimini, T. Robinson, M. Sertoli, S.A. Silburn, G. Sips, P. Sirén, Ž. Štancar, H.J. Sun, G. Szepesi, D. Taylor, E. Tholerus, B. Thomas, G. Verdoolaege, P. Vincenzi, B. Viola, N. Vianello, T. Wilson, and JET Contributors

Subjects
L-H transition, power threshold, tokamaks, Tritium, DT, JET-ILW, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The recent deuterium–tritium campaign in JET-ILW (DTE2) has provided a unique opportunity to study the isotope dependence of the L-H power threshold in an ITER-like wall environment (Be wall and W divertor). Here we present results from dedicated L-H transition experiments at JET-ILW, documenting the power threshold in tritium and deuterium–tritium plasmas, comparing them with the matching deuterium and hydrogen datasets. From earlier experiments in JET-ILW it is known that as plasma isotopic composition changes from deuterium, through varying deuterium/hydrogen concentrations, to pure hydrogen, the value of the line averaged density at which the threshold is minimum, ${\bar n_{{\text{e}},{\text{min}}}}$ , increases, leading us to expect that ${\bar n_{{\text{e}},{\text{min}}}}$ (T) < ${\bar n_{{\text{e}},{\text{min}}}}$ (DT) < ${\bar n_{{\text{e}},{\text{min}}}}$ (D) < ${\bar n_{{\text{e}},{\text{min}}}}$ (H). The new power threshold data confirms these expectations in most cases, with the corresponding ordering of the minimum power thresholds. We present a comparison of this data to power threshold scalings, used for extrapolation to future devices such as ITER and DEMO.

Published
2023
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16. Impact of interaction between RF waves and fast NBI ions on the fusion performance in JET DTE2 campaign

Author

K.K. Kirov, C.D. Challis, E. De la Luna, J. Eriksson, D. Gallart, J. Garcia, M. Gorelenkova, J. Hobirk, P. Jacquet, A. Kappatou, Y.O. Kazakov, D. Keeling, D. King, E. Lerche, C. Maggi, J. Mailloux, P. Mantica, M. Mantsinen, M. Maslov, S. Menmuir, P. Siren, Z. Stancar, D. Van Eester, and JET Contributors

Subjects
RF waves, fast ions, DT plasma, JET, fusion performance, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

This work presents a study of the interaction between radio frequency (RF) waves used for ion cyclotron resonance heating and the fast deuterium (D) and tritium (T) neutral Beam injected (NBI) ions in DT plasma. The focus is on the effects of this interaction, also referred to as synergistic effects, on the fusion performance in the recent JET DTE2 campaign. Experimental data from dedicated pulses at 3.43 T/2.3 MA heated at (i) 51.4 MHz, giving the central minority H and n = 2 D, and at (ii) 32.2 MHz for the central minority ^3 He and n = 2 T. Resonances are analysed and conclusions are drawn and supported by modelling of the synergistic effects. Modelling with transport code TRANSP runs with and without the RF kick operator predict a moderate increase, of about 10%, in DT rates for the case of the RF wave—fast D NBI ion interactions at the n = 2 harmonic of ion cyclotron resonance, and a negligible impact due to synergistic interaction between fast T NBI ions and RF waves. JETTO modelling gives a 29% enhancement in fusion rates due to the interction between RF waves and fast D NBI ions, and an 18% enhancement in fast T NBI ions. Analysis of experimental neutron rates compared to TRANSP predictions without synergistic effects and magnetic proton recoil neutron spectrometer indicate an enhancement of approximately 25%–28% in fusion rates due to RF interaction with fast D ions, and an enhancement of approximately 5%–8% when RF waves and fast T NBI ions are interacting. The contributions of various heating and fast ion sources are assessed and discussed.

Published
2023
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17. Global scaling of the heat transport in fusion plasmas

Author

Sara Moradi, Johan Anderson, Michele Romanelli, Hyun-Tae Kim, JET contributors, X. Litaudon, S. Abduallev, M. Abhangi, P. Abreu, M. Afzal, K. M. Aggarwal, T. Ahlgren, J. H. Ahn, L. Aho-Mantila, N. Aiba, M. Airila, R. Albanese, V. Aldred, D. Alegre, E. Alessi, P. Aleynikov, A. Alfier, A. Alkseev, M. Allinson, B. Alper, E. Alves, G. Ambrosino, R. Ambrosino, L. Amicucci, V. Amosov, E. Andersson Sundén, M. Angelone, M. Anghel, C. Angioni, L. Appel, C. Appelbee, P. Arena, M. Ariola, H. Arnichand, S. Arshad, A. Ash, N. Ashikawa, V. Aslanyan, O. Asunta, F. Auriemma, Y. Austin, L. Avotina, M. D. Axton, C. Ayres, M. Bacharis, A. Baciero, D. Baião, S. Bailey, A. Baker, I. Balboa, M. Balden, N. Balshaw, R. Bament, J. W. Banks, Y. F. Baranov, M. A. Barnard, D. Barnes, M. Barnes, R. Barnsley, A. Baron Wiechec, L. Barrera Orte, M. Baruzzo, V. Basiuk, M. Bassan, R. Bastow, A. Batista, P. Batistoni, R. Baughan, B. Bauvir, L. Baylor, B. Bazylev, J. Beal, P. S. Beaumont, M. Beckers, B. Beckett, A. Becoulet, N. Bekris, M. Beldishevski, K. Bell, F. Belli, M. Bellinger, É. Belonohy, N. Ben Ayed, N. A. Benterman, H. Bergsȧker, J. Bernardo, M. Bernert, M. Berry, L. Bertalot, C. Besliu, M. Beurskens, B. Bieg, J. Bielecki, T. Biewer, M. Bigi, P. Bìlkovà, F. Binda, A. Bisoffi, J. P. S. Bizarro, C. Björkas, J. Blackburn, K. Blackman, T. R. Blackman, P. Blanchard, P. Blatchford, V. Bobkov, A. Boboc, G. Bodnàr, O. Bogar, I. Bolshakova, T. Bolzonella, N. Bonanomi, F. Bonelli, J. Boom, J. Booth, D. Borba, D. Borodin, I. Borodkina, A. Botrugno, C. Bottereau, P. Boulting, C. Bourdelle, M. Bowden, C. Bower, C. Bowman, T. Boyce, C. Boyd, H. J. Boyer, J. M. A. Bradshaw, V. Braic, R. Bravanec, B. Breizman, S. Bremond, P. D. Brennan, S. Breton, A. Brett, S. Brezinsek, M. D. J. Bright, M. Brix, W. Broeckx, M. Brombin, A. Brosawski, D. P. D. Brown, M. Brown, E. Bruno, J. Bucalossi, J. Buch, J. Buchanan, M. A. Buckley, R. Budny, H. Bufferand, M. Bulman, N. Bulmer, P. Bunting, P. Buratti, A. Burckhart, A. Buscarino, A. Busse, N. K. Butler, I. Bykov, J. Byrne, P. Cahyna, G. Calabrò, I. Calvo, Y. Camenen, P. Camp, D. C. Campling, J. Cane, B. Cannas, A. J. Capel, P. J. Card, A. Cardinali, P. Carman, M. Carr, D. Carralero, L. Carraro, B. B. Carvalho, I. Carvalho, P. Carvalho, F. J. Casson, C. Castaldo, N. Catarino, J. Caumont, F. Causa, R. Cavazzana, K. Cave-Ayland, M. Cavinato, M. Cecconello, S. Ceccuzzi, E. Cecil, A. Cenedese, R. Cesario, C. D. Challis, M. Chandler, D. Chandra, C. S. Chang, A. Chankin, I. T. Chapman, S. C. Chapman, M. Chernyshova, G. Chitarin, G. Ciraolo, D. Ciric, J. Citrin, F. Clairet, E. Clark, M. Clark, R. Clarkson, D. Clatworthy, C. Clements, M. Cleverly, J. P. Coad, P. A. Coates, A. Cobalt, V. Coccorese, V. Cocilovo, S. Coda, R. Coelho, J. W. Coenen, I. Coffey, L. Colas, S. Collins, D. Conka, S. Conroy, N. Conway, D. Coombs, D. Cooper, S. R. Cooper, C. Corradino, Y. Corre, G. Corrigan, S. Cortes, D. Coster, A. S. Couchman, M. P. Cox, T. Craciunescu, S. Cramp, R. Craven, F. Crisanti, G. Croci, D. Croft, K. Crombé, R. Crowe, N. Cruz, G. Cseh, A. Cufar, A. Cullen, M. Curuia, A. Czarnecka, H. Dabirikhah, P. Dalgliesh, S. Dalley, J. Dankowski, D. Darrow, O. Davies, W. Davis, C. Day, I. E. Day, M. De Bock, A. de Castro, E. de la Cal, E. de la Luna, G. De Masi, J. L. de Pablos, G. De Temmerman, G. De Tommasi, P. de Vries, K. Deakin, J. Deane, F. Degli Agostini, R. Dejarnac, E. Delabie, N. den Harder, R. O. Dendy, J. Denis, P. Denner, S. Devaux, P. Devynck, F. Di Maio, A. Di Siena, C. Di Troia, P. Dinca, R. Dinca, B. Ding, T. Dittmar, H. Doerk, R. P. Doerner, T. Donné, S. E. Dorling, S. Dormido-Canto, S. Doswon, D. Douai, P. T. Doyle, A. Drenik, P. Drewelow, P. Drews, Ph. Duckworth, R. Dumont, P. Dumortier, D. Dunai, M. Dunne, I. Duran, F. Durodié, P. Dutta, B. P. Duval, R. Dux, K. Dylst, N. Dzysiuk, P. V. Edappala, J. Edmond, A. M. Edwards, J. Edwards, Th. Eich, A. Ekedahl, R. El-Jorf, C. G. Elsmore, M. Enachescu, G. Ericsson, F. Eriksson, J. Eriksson, L. G. Eriksson, B. Esposito, S. Esquembri, H. G. Esser, D. Esteve, B. Evans, G. E. Evans, G. Evison, G. D. Ewart, D. Fagan, M. Faitsch, D. Falie, A. Fanni, A. Fasoli, J. M. Faustin, N. Fawlk, L. Fazendeiro, N. Fedorczak, R. C. Felton, K. Fenton, A. Fernades, H. Fernandes, J. Ferreira, J. A. Fessey, O. Février, O. Ficker, A. Field, S. Fietz, A. Figueiredo, J. Figueiredo, A. Fil, P. Finburg, M. Firdaouss, U. Fischer, L. Fittill, M. Fitzgerald, D. Flammini, J. Flanagan, C. Fleming, K. Flinders, N. Fonnesu, J. M. Fontdecaba, A. Formisano, L. Forsythe, L. Fortuna, E. Fortuna-Zalesna, M. Fortune, S. Foster, T. Franke, T. Franklin, M. Frasca, L. Frassinetti, M. Freisinger, R. Fresa, D. Frigione, V. Fuchs, D. Fuller, S. Futatani, J. Fyvie, K. Gàl, D. Galassi, K. Galazka, J. Galdon-Quiroga, J. Gallagher, D. Gallart, R. Galvão, X. Gao, Y. Gao, J. Garcia, A. Garcia-Carrasco, M. Garca-Munoz, J.-L. Gardarein, L. Garzotti, P. Gaudio, E. Gauthier, D. F. Gear, S. J. Gee, B. Geiger, M. Gelfusa, S. Gerasimov, G. Gervasini, M. Gethins, Z. Ghani, M. Ghate, M. Gherendi, J. C. Giacalone, L. Giacomelli, C. S. Gibson, T. Giegerich, C. Gil, L. Gil, S. Gilligan, D. Gin, E. Giovannozzi, J. B. Girardo, C. Giroud, G. Giruzzi, S. Glöggler, J. Godwin, J. Goff, P. Gohil, V. Goloborod'ko, R. Gomes, B. Goncalves, M. Goniche, M. Goodliffe, A. Goodyear, G. Gorini, M. Gosk, R. Goulding, A. Goussarov, R. Gowland, B. Graham, M. E. Graham, J. P. Graves, N. Grazier, P. Grazier, N. R. Green, H. Greuner, B. Grierson, F. S. Griph, C. Grisolia, D. Grist, M. Groth, R. Grove, C. N. Grundy, J. Grzonka, D. Guard, C. Guérard, C. Guillemaut, R. Guirlet, C. Gurl, H. H. Utoh, L. J. Hackett, S. Hacquin, A. Hagar, R. Hager, A. Hakola, M. Halitovs, S. J. Hall, S. P. Hallworth Cook, C. Hamlyn-Harris, K. Hammond, C. Harrington, J. Harrison, D. Harting, F. Hasenbeck, Y. Hatano, D. R. Hatch, T. D. V. Haupt, J. Hawes, N. C. Hawkes, J. Hawkins, P. Hawkins, P. W. Haydon, N. Hayter, S. Hazel, P. J. L. Heesterman, K. Heinola, C. Hellesen, T. Hellsten, W. Helou, O. N. Hemming, T. C. Hender, M. Henderson, S. S. Henderson, R. Henriques, D. Hepple, G. Hermon, P. Hertout, C. Hidalgo, E. G. Highcock, M. Hill, J. Hillairet, J. Hillesheim, D. Hillis, K. Hizanidis, A. Hjalmarsson, J. Hobirk, E. Hodille, C. H. A. Hogben, G. M. D. Hogeweij, A. Hollingsworth, S. Hollis, D. A. Homfray, J. Horàcek, G. Hornung, A. R. Horton, L. D. Horton, L. Horvath, S. P. Hotchin, M. R. Hough, P. J. Howarth, A. Hubbard, A. Huber, V. Huber, T. M. Huddleston, M. Hughes, G. T. A. Huijsmans, C. L. Hunter, P. Huynh, A. M. Hynes, D. Iglesias, N. Imazawa, F. Imbeaux, M. Imrìŝek, M. Incelli, P. Innocente, M. Irishkin, I. Ivanova-Stanik, S. Jachmich, A. S. Jacobsen, P. Jacquet, J. Jansons, A. Jardin, A. Järvinen, F. Jaulmes, S. Jednoróq, I. Jenkins, C. Jeong, I. Jepu, E. Joffrin, R. Johnson, T. Johnson, Jane Johnston, L. Joita, G. Jones, T. T. C. Jones, K. K. Hoshino, A. Kallenbach, K. Kamiya, J. Kaniewski, A. Kantor, A. Kappatou, J. Karhunen, D. Karkinsky, I. Karnowska, M. Kaufman, G. Kaveney, Y. Kazakov, V. Kazantzidis, D. L. Keeling, T. Keenan, J. Keep, M. Kempenaars, C. Kennedy, D. Kenny, J. Kent, O. N. Kent, E. Khilkevich, H. T. Kim, H. S. Kim, A. Kinch, C. King, D. King, R. F. King, D. J. Kinna, V. Kiptily, A. Kirk, K. Kirov, A. Kirschner, G. Kizane, C. Klepper, A. Klix, P. Knight, S. J. Knipe, S. Knott, T. Kobuchi, F. Köchl, G. Kocsis, I. Kodeli, L. Kogan, D. Kogut, S. Koivuranta, Y. Kominis, M. Köppen, B. Kos, T. Koskela, H. R. Koslowski, M. Koubiti, M. Kovari, E. Kowalska-Strzeciwilk, A. Krasilnikov, V. Krasilnikov, N. Krawczyk, M. Kresina, K. Krieger, A. Krivska, U. Kruezi, I. Ksiazek, A. Kukushkin, A. Kundu, T. Kurki-Suonio, S. Kwak, R. Kwiatkowski, O. J. Kwon, L. Laguardia, A. Lahtinen, A. Laing, N. Lam, H. T. Lambertz, C. Lane, P. T. Lang, S. Lanthaler, J. Lapins, A. Lasa, J. R. Last, E. Laszynska, R. Lawless, A. Lawson, K. D. Lawson, A. Lazaros, E. Lazzaro, J. Leddy, S. Lee, X. Lefebvre, H. J. Leggate, J. Lehmann, M. Lehnen, D. Leichtle, P. Leichuer, F. Leipold, I. Lengar, M. Lennholm, E. Lerche, A. Lescinskis, S. Lesnoj, E. Letellier, M. Leyland, W. Leysen, L. Li, Y. Liang, J. Likonen, J. Linke, Ch. Linsmeier, B. Lipschultz, G. Liu, Y. Liu, V. P. Lo Schiavo, T. Loarer, A. Loarte, R. C. Lobel, B. Lomanowski, P. J. Lomas, J. Lönnroth, J. M. López, J. López-Razola, R. Lorenzini, U. Losada, J. J. Lovell, A. B. Loving, C. Lowry, T. Luce, R. M. A. Lucock, A. Lukin, C. Luna, M. Lungaroni, C. P. Lungu, M. Lungu, A. Lunniss, I. Lupelli, A. Lyssoivan, N. Macdonald, P. Macheta, K. Maczewa, B. Magesh, P. Maget, C. Maggi, H. Maier, J. Mailloux, T. Makkonen, R. Makwana, A. Malaquias, A. Malizia, P. Manas, A. Manning, M. E. Manso, P. Mantica, M. Mantsinen, A. Manzanares, Ph. Maquet, Y. Marandet, N. Marcenko, C. Marchetto, O. Marchuk, M. Marinelli, M. Marinucci, T. Markovic, D. Marocco, L. Marot, C. A. Marren, R. Marshal, A. Martin, Y. Martin, A. Martín de Aguilera, F. J. Martínez, J. R. Martín-Solís, Y. Martynova, S. Maruyama, A. Masiello, M. Maslov, S. Matejcik, M. Mattei, G. F. Matthews, F. Maviglia, M. Mayer, M. L. Mayoral, T. May-Smith, D. Mazon, C. Mazzotta, R. McAdams, P. J. McCarthy, K. G. McClements, O. McCormack, P. A. McCullen, D. McDonald, S. McIntosh, R. McKean, J. McKehon, R. C. Meadows, A. Meakins, F. Medina, M. Medland, S. Medley, S. Meigh, A. G. Meigs, G. Meisl, S. Meitner, L. Meneses, S. Menmuir, K. Mergia, I. R. Merrigan, Ph. Mertens, S. Meshchaninov, A. Messiaen, H. Meyer, S. Mianowski, R. Michling, D. Middleton-Gear, J. Miettunen, F. Militello, E. Militello-Asp, G. Miloshevsky, F. Mink, S. Minucci, Y. Miyoshi, J. Mlynàr, D. Molina, I. Monakhov, M. Moneti, R. Mooney, S. Moradi, S. Mordijck, L. Moreira, R. Moreno, F. Moro, A. W. Morris, J. Morris, L. Moser, S. Mosher, D. Moulton, A. Murari, A. Muraro, S. Murphy, N. N. Asakura, Y. S. Na, F. Nabais, R. Naish, T. Nakano, E. Nardon, V. Naulin, M. F. F. Nave, I. Nedzelski, G. Nemtsev, F. Nespoli, A. Neto, R. Neu, V. S. Neverov, M. Newman, K. J. Nicholls, T. Nicolas, A. H. Nielsen, P. Nielsen, E. Nilsson, D. Nishijima, C. Noble, M. Nocente, D. Nodwell, K. Nordlund, H. Nordman, R. Nouailletas, I. Nunes, M. Oberkofler, T. Odupitan, M. T. Ogawa, T. O'Gorman, M. Okabayashi, R. Olney, O. Omolayo, M. O'Mullane, J. Ongena, F. Orsitto, J. Orszagh, B. I. Oswuigwe, R. Otin, A. Owen, R. Paccagnella, N. Pace, D. Pacella, L. W. Packer, A. Page, E. Pajuste, S. Palazzo, S. Pamela, S. Panja, P. Papp, R. Paprok, V. Parail, M. Park, F. Parra Diaz, M. Parsons, R. Pasqualotto, A. Patel, S. Pathak, D. Paton, H. Patten, A. Pau, E. Pawelec, C. Paz Soldan, A. Peackoc, I. J. Pearson, S.-P. Pehkonen, E. Peluso, C. Penot, A. Pereira, R. Pereira, P. P. Pereira Puglia, C. Perez von Thun, S. Peruzzo, S. Peschanyi, M. Peterka, P. Petersson, G. Petravich, A. Petre, N. Petrella, V. Petrzilka, Y. Peysson, D. Pfefferlé, V. Philipps, M. Pillon, G. Pintsuk, P. Piovesan, A. Pires dos Reis, L. Piron, A. Pironti, F. Pisano, R. Pitts, F. Pizzo, V. Plyusnin, N. Pomaro, O. G. Pompilian, P. J. Pool, S. Popovichev, M. T. Porfiri, C. Porosnicu, M. Porton, G. Possnert, S. Potzel, T. Powell, J. Pozzi, V. Prajapati, R. Prakash, G. Prestopino, D. Price, M. Price, R. Price, P. Prior, R. Proudfoot, G. Pucella, P. Puglia, M. E. Puiatti, D. Pulley, K. Purahoo, Th. Pütterich, E. Rachlew, M. Rack, R. Ragona, M. S. J. Rainford, A. Rakha, G. Ramogida, S. Ranjan, C. J. Rapson, J. J. Rasmussen, K. Rathod, G. Rattà, S. Ratynskaia, G. Ravera, C. Rayner, M. Rebai, D. Reece, A. Reed, D. Réfy, B. Regan, J. Regana, M. Reich, N. Reid, F. Reimold, M. Reinhart, M. Reinke, D. Reiser, D. Rendell, C. Reux, S. D. A. Reyes Cortes, S. Reynolds, V. Riccardo, N. Richardson, K. Riddle, D. Rigamonti, F. G. Rimini, J. Risner, M. Riva, C. Roach, R. J. Robins, S. A. Robinson, T. Robinson, D. W. Robson, R. Roccella, R. Rodionov, P. Rodrigues, J. Rodriguez, V. Rohde, F. Romanelli, M. Romanelli, S. Romanelli, J. Romazanov, S. Rowe, M. Rubel, G. Rubinacci, G. Rubino, L. Ruchko, M. Ruiz, C. Ruset, J. Rzadkiewicz, S. Saarelma, R. Sabot, E. Safi, P. Sagar, G. Saibene, F. Saint-Laurent, M. Salewski, A. Salmi, R. Salmon, F. Salzedas, D. Samaddar, U. Samm, D. Sandiford, P. Santa, M. I. K. Santala, B. Santos, A. Santucci, F. Sartori, R. Sartori, O. Sauter, R. Scannell, T. Schlummer, K. Schmid, V. Schmidt, S. Schmuck, M. Schneider, K. Schöpf, D. Schwörer, S. D. Scott, G. Sergienko, M. Sertoli, A. Shabbir, S. E. Sharapov, A. Shaw, R. Shaw, H. Sheikh, A. Shepherd, A. Shevelev, A. Shumack, G. Sias, M. Sibbald, B. Sieglin, S. Silburn, A. Silva, C. Silva, P. A. Simmons, J. Simpson, J. Simpson-Hutchinson, A. Sinha, S. K. Sipilä, A. C. C. Sips, P. Sirén, A. Sirinelli, H. Sjöstrand, M. Skiba, R. Skilton, K. Slabkowska, B. Slade, N. Smith, P. G. Smith, R. Smith, T. J. Smith, M. Smithies, L. Snoj, S. Soare, E. R. Solano, A. Somers, C. Sommariva, P. Sonato, A. Sopplesa, J. Sousa, C. Sozzi, S. Spagnolo, T. Spelzini, F. Spineanu, G. Stables, I. Stamatelatos, M. F. Stamp, P. Staniec, G. Stankunas, C. Stan-Sion, M. J. Stead, E. Stefanikova, I. Stepanov, A. V. Stephen, M. Stephen, A. Stevens, B. D. Stevens, J. Strachan, P. Strand, H. R. Strauss, P. Ström, G. Stubbs, W. Studholme, F. Subba, H. P. Summers, J. Svensson, L. Swiderski, T. Szabolics, M. Szawlowski, G. Szepesi, T. T. Suzuki, B. Tàl, T. Tala, A. R. Talbot, S. Talebzadeh, C. Taliercio, P. Tamain, C. Tame, W. Tang, M. Tardocchi, L. Taroni, D. Taylor, K. A. Taylor, D. Tegnered, G. Telesca, N. Teplova, D. Terranova, D. Testa, E. Tholerus, J. Thomas, J. D. Thomas, P. Thomas, A. Thompson, C.-A. Thompson, V. K. Thompson, L. Thorne, A. Thornton, A. S. Thrysoe, P. A. Tigwell, N. Tipton, I. Tiseanu, H. Tojo, M. Tokitani, P. Tolias, M. Tomes, P. Tonner, M. Towndrow, P. Trimble, M. Tripsky, M. Tsalas, P. Tsavalas, D. Tskhakaya jun, I. Turner, M. M. Turner, M. Turnyanskiy, G. Tvalashvili, S. G. J. Tyrrell, A. Uccello, Z. Ul-Abidin, J. Uljanovs, D. Ulyatt, H. Urano, I. Uytdenhouwen, A. P. Vadgama, D. Valcarcel, M. Valentinuzzi, M. Valisa, P. Vallejos Olivares, M. Valovic, M. Van De Mortel, D. Van Eester, W. Van Renterghem, G. J. van Rooij, J. Varje, S. Varoutis, S. Vartanian, K. Vasava, T. Vasilopoulou, J. Vega, G. Verdoolaege, R. Verhoeven, C. Verona, G. Verona Rinati, E. Veshchev, N. Vianello, J. Vicente, E. Viezzer, S. Villari, F. Villone, P. Vincenzi, I. Vinyar, B. Viola, A. Vitins, Z. Vizvary, M. Vlad, I. Voitsekhovitch, P. Vondràcek, N. Vora, T. Vu, W. W. Pires de Sa, B. Wakeling, C. W. F. Waldon, N. Walkden, M. Walker, R. Walker, M. Walsh, E. Wang, N. Wang, S. Warder, R. J. Warren, J. Waterhouse, N. W. Watkins, C. Watts, T. Wauters, A. Weckmann, J. Weiland, H. Weisen, M. Weiszflog, C. Wellstood, A. T. West, M. R. Wheatley, S. Whetham, A. M. Whitehead, B. D. Whitehead, A. M. Widdowson, S. Wiesen, J. Wilkinson, J. Williams, M. Williams, A. R. Wilson, D. J. Wilson, H. R. Wilson, J. Wilson, M. Wischmeier, G. Withenshaw, A. Withycombe, D. M. Witts, D. Wood, R. Wood, C. Woodley, S. Wray, J. Wright, J. C. Wright, J. Wu, S. Wukitch, A. Wynn, T. Xu, D. Yadikin, W. Yanling, L. Yao, V. Yavorskij, M. G. Yoo, C. Young, D. Young, I. D. Young, R. Young, J. Zacks, R. Zagorski, F. S. Zaitsev, R. Zanino, A. Zarins, K. D. Zastrow, M. Zerbini, W. Zhang, Y. Zhou, E. Zilli, V. Zoita, S. Zoletnik, and I. Zychor

Subjects
Physics, QC1-999
Abstract

A global heat flux model based on a fractional derivative of plasma pressure is proposed for the heat transport in fusion plasmas. The degree of the fractional derivative of the heat flux, α, is defined through the power balance analysis of the steady state. The model was used to obtain the experimental values of α for a large database of the Joint European Torus (JET) carbon-wall as well as ITER like-wall plasmas. The fractional degrees of the electron heat flux are found to be α

Published
2020
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18. Design and measuring performance of the ITER plasma position reflectometer in-port-plug antennas

Author

E. de la Luna, E.J. Blanco, T. Estrada, J. Martínez-Fernández, and A. Cappa

Subjects
Physics, Mechanical Engineering, Acoustics, Finite-difference time-domain method, Phase (waves), Near and far field, 01 natural sciences, 010305 fluids & plasmas, Ray tracing (physics), Amplitude, Nuclear Energy and Engineering, Position (vector), 0103 physical sciences, Spectrogram, General Materials Science, Antenna (radio), 010306 general physics, Civil and Structural Engineering
Abstract

Design parameters of the ITER Plasma Position Reflectometer (PPR) in-port-plug antennas are determined and their measurement performance is assessed using 2D full wave analysis. Two ITER scenarios were selected in order to determine the optimum antenna position and orientation, namely the ITER QDT = 10 baseline scenario (15 MA) and the low density one planned for the initial non-active phase at 7.5 MA. Using them to feed a 3D ray tracing code, the spatial position and optimum orientation angles of each set of emission and detection antennas were determined. Additionally, a far field analysis of the launching radiation patterns led to the definition of the antenna dimensions in terms of optimal power coupling. After this preliminary work, 2D full wave simulations using a finite difference time domain (FDTD) code were carried out to assess the measurement performance of the system. To this end, the detected wave amplitudes and phases were evaluated for each scenario and two models of the scrape-off layer (SOL) density profiles. By calculating the spectrogram of the complex amplitude of the detected wave, the reconstruction of the plasma density profile can be made and be directly compared with the input profiles. As a result from this synthetic diagnostic analysis, an estimation of the error in the determination of the last closed flux surface position was possible.

Published
2019
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19. Pedestal structure, stability and scalings in JET-ILW: the EUROfusion JET-ILW pedestal database

Author

M. Groth, Geert Verdoolaege, Petra Bilkova, Frederic Imbeaux, P. Bohm, Benoit Labit, E. Giovannozzi, C. F. Maggi, S. Saarelma, Jet Contributors, Richard Fridström, M. Owsiak, M. Dunne, E. de la Luna, Lorenzo Frassinetti, R. Scannell, J. C. Hillesheim, and JET Contributors

Subjects
Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, GLOBAL CONFINEMENT, ELMY H-MODES, pedestal scaling, 01 natural sciences, Stability (probability), 010305 fluids & plasmas, ENERGY, Pedestal, DENSITY LIMIT, Physics::Plasma Physics, DEPENDENCE, 0103 physical sciences, 010306 general physics, EDGE LOCALIZED MODES, Physics, Jet (fluid), Mechanics, pedestal structure, Condensed Matter Physics, TRANSPORT, Physics and Astronomy, SIMULATION, PB stability, 2-TERM MODEL, PARTICLE LOSSES
Abstract

The EUROfusion JET-ILW pedestal database is described, with emphasis on three main issues. First, the technical aspects are introduced, including a description of the data selection, the datasets, the diagnostics used, the experimental and theoretical methods implemented and the main definitions. Second, the JET-ILW pedestal structure and stability are described. In particular, the work describes the links between the engineering parameters (power, gas and divertor configuration) and the disagreement with the peeling-ballooning (PB) model implemented with ideal magnetohydrodynamics equations. Specifically, the work clarifies why the JET-ILW pedestal tends to be far from the PB boundary at high gas and high power, showing that a universal threshold in power and gas cannot be found but that the relative shift (the distance between the position of the pedestal density and of the pedestal temperature) plays a key role. These links are then used to achieve an empirical explanation of the behavior of the JET-ILW pedestal pressure with gas, power and divertor configuration. Third, the pedestal database is used to revise the scaling law of the pedestal stored energy. The work shows a reasonable agreement with the earlier Cordey scaling in terms of plasma current and triangularity dependence, but highlights some differences in terms of power and isotope mass dependence.

Published
2021
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20. Corrigendum: characterisation of highly radiating neon seeded plasmas in JET-ILW (2019 Nucl. Fusion 59 126031), Nuclear Fusion 60, 079501 (2020)

Author

M. Sertoli, Maryna Chernyshova, A. Huber, E. R. Solano, Ewa Kowalska-Strzęciwilk, G. Calabrò, H. J. Sun, M. Wischmeier, S. Wiesen, M. Bernert, Matthew Reinke, C.G. Lowry, E. Fable, E. de la Luna, U. Stroth, C. F. Maggi, Jet Contributors, S. Glöggler, and JET Contributors

Subjects
Nuclear and High Energy Physics, Jet (fluid), Materials science, Tokamak, High radiation, chemistry.chemical_element, Plasma, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, law.invention, Neon, chemistry, law, 0103 physical sciences, Plasma, Fusion, JET, Neon, Radiation, Seeding, Atomic physics, 010306 general physics
Abstract

This is the accepted manuscript (post-peer reviewed) of the following final paper: " Glöggler, S., Wischmeier, M., Fable, E., Solano, E.R., Sertoli, M., Bernert, M., Calabrò, G., Chernyshova, M., Huber, A., Kowalska-Strzȩciwilk, E., Lowry, C., De La Luna, E., Maggi, C.F., Stroth, U., Sun, H.J., Reinke, M.L., Wiesen, S., Characterisation of highly radiating neon seeded plasmas in JET-ILW, (2019) Nuclear Fusion, 59 (12), art. no. 126031,https://doi.org/10.1088/1741-4326/ab3f7a"

Published
2019
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22. Dimensionless scalings of confinement, heat transport and pedestal stability in JET-ILW and comparison with JET-C

Author

Hyun-Tae Kim, S. Menmuir, Jet Contributors, J. Flanagan, Elisabeth Rachlew, C. Giroud, P. Drewelow, U. Kruezi, E. Stefanikova, Petra Bilkova, P. J. Lomas, C. F. Maggi, E. de la Luna, M. N. A. Beurskens, M. Peterka, Lorenzo Frassinetti, Isabel L. Nunes, N Hawks, M. Kempenaars, S. Saarelma, J. E. Boom, L. Garzotti, F.G. Rimini, Ivan Lupelli, E. Delabie, A. Loarte, B. Lomanowski, M. Romanelli, L. Meneses, E. Joffrin, and JET Contributors

Subjects
DIII-D, Gyroradius, Astrophysics::High Energy Astrophysical Phenomena, Atmospheric-pressure plasma, Collisionality, complex mixtures, 01 natural sciences, 010305 fluids & plasmas, Physics::Fluid Dynamics, Pedestal, Physics::Plasma Physics, 0103 physical sciences, 010306 general physics, Physics, Jet (fluid), Mechanics, respiratory system, equipment and supplies, Condensed Matter Physics, Nuclear Energy and Engineering, Beta (plasma physics), Physics::Space Physics, High Energy Physics::Experiment, human activities, circulatory and respiratory physiology, Dimensionless quantity
Abstract

Three dimensionless scans in the normalized Larmor radius rho*, normalized collisionality nu* and normalized plasma pressure beta have been performed in JET with the ITER-like wall (JET-ILW). The n ...

Published
2017
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23. Power and particle fluxes to plasma-facing components in mitigated-ELM H-mode discharges on JET

Author

W. Fundamenski, Y. Liang, S. Jachmich, T. Eich, Jet-Efda Contributors, Stéphane Devaux, C. Giroud, E. de la Luna, H. R. Koslowski, S. Brezinsek, H. Thomsen, G. P. Maddison, and G. Arnoux

Subjects
Nuclear and High Energy Physics, Jet (fluid), Drop (liquid), chemistry.chemical_element, Plasma, Nitrogen, Power (physics), Pedestal, Nuclear Energy and Engineering, chemistry, Physics::Plasma Physics, Impurity, General Materials Science, Seeding, Atomic physics
Abstract

The effect of ELM-mitigation techniques such as the use of magnetic-field perturbations, gas fuelling and impurity seeding using nitrogen has been studied. With increasing ELM frequency the divertor–heat-flux factor reduces only weakly. The heat-flux factor, which has been analysed taking into account ELM-profile broadening and strike-point movement and which is proportional to the surface-temperature rise due to the heat pulse during the ELM, decreases with confinement and pedestal pressure at the same rate for mitigated ELMs using gas fuelling and magnetic-perturbation fields. Only at very high fuelling rates of nitrogen is a drastic drop of the heat-flux factor with modest confinement reduction found.

Published
2011
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24. Strike-point splitting induced by external magnetic perturbations: Observations on JET and MAST and associated modelling

Author

P. Denner, A. Kirk, Eric Nardon, Youwen Sun, S. Jachmich, Alberto Alfier, E. de la Luna, D. Harting, T. Eich, Yunfeng Liang, Stéphane Devaux, H. R. Koslowski, P. Cahyna, T. Gerbaud, G. De Temmerman, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Infrared, Field line, Plasma, Magnetic response, 01 natural sciences, 010305 fluids & plasmas, Computational physics, Nuclear magnetic resonance, Nuclear Energy and Engineering, Heat flux, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, General Materials Science, 010306 general physics
Abstract

International audience; Heat flux deposition profiles, calculated from infrared imaging, are presented for JET and MAST cases in the presence of external magnetic perturbations. In L-mode, a clear splitting of the strike-point is observed and well reproduced by modelling based on field line tracing with no plasma magnetic response included (vacuum field approximation). In H-mode, in contrast, the splitting is not clearly observed in spite of being expected from vacuum field modelling. As illustrated by modelling results, screening effects could explain the absence of a clear splitting in H-mode. (C) 2010 Elsevier B.V. All rights reserved.Assoc EURATOM IPP CR, Inst Plasma Phys AS CR Vvi, Prague, Czech Republic.Max Planck Inst Plasma Phys, D-85748 Garching, Germany.Culham Sci Ctr, EURATOM CCFE Fus Assoc, Abingdon OX14 3DB, Oxon, England.Assoc Euratom Enea Fus, Consorzio RFX, I-35127 Padua, Italy.Asociac EURATOM CIEMAT, Lab Nacl Fus, Madrid, Spain.FOM Inst Plasma Phys Rijnhuizen, NL-3439 MN Nieuwegein, Netherlands.Ecole Polytech, CNRS, UMR 7648, LPTP, F-91128 Palaiseau, France.Forschungszentrum Julich, Assoc EURATOM FZJ, D-52425 Julich, Germany.TEC, EURATOM Belgian State Assoc, LPP ERM KMS, Brussels, Belgium.

Published
2011
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26. Perturbation of tokamak magnetic surfaces by applied toroidally asymmetric magnetic fields

Author

S.K. Erents, M.F. Stamp, Jet-Efda Contributors, E. de la Luna, T. C. Hender, A. Savchkov, I. T. Chapman, S. Shibaev, D. F. Howell, Mikhail Gryaznevich, and R. Scannell

Subjects
Physics, Nuclear and High Energy Physics, Mega Ampere Spherical Tokamak, Tokamak, Joint European Torus, Magnetic confinement fusion, Plasma, Spherical tokamak, Condensed Matter Physics, Magnetic field, law.invention, Amplitude, Physics::Plasma Physics, law, Atomic physics
Abstract

The effects of applied three-dimensional magnetic error fields on magnetic surfaces are measured in both the Joint European Torus (JET) and the Mega Ampere Spherical Tokamak (MAST). Static perturbation fields with various amplitudes have been applied in both devices using non-axisymmetric coils producing a dominantly n = 1 magnetic field to systematically perturb the plasma flux surfaces. The displacement of the plasma boundary is found to increase linearly with the strength of the applied field, and agrees well with predictive modelling which superimposes vacuum non-axisymmetric fields on a 2D equilibrium.

Published
2007
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27. H-mode access in the low density regime on JET

Author

R. Sartori, N.C. Hawkes, Jet Contributors, A. Korotkov, E. de la Luna, S. Hacquin, Y. Andrew, E. Righi, M. G. O'Mullane, D.F. Howell, L. D. Horton, and A. Huber

Subjects
Physics, Jet (fluid), Electron density, Divertor, Magnetic confinement fusion, chemistry.chemical_element, Condensed Matter Physics, Neon, Pedestal, Nuclear Energy and Engineering, chemistry, Electron temperature, Atomic physics, Bar (unit)
Abstract

1 H-mode access studies under conditions of very low plasma density provide valuable information on the, physics of the edge transport barrier formation and are an important part of the operational scenario development for the next step fusion device, ITER. JET operation with a very low edge electron density, (n) over bar (e) = 0.8-1.4 x 10(19) m(-3), with the MkII gas box septum divertor was found to have a significant effect on the power threshold for the L-H transition, P-th. A sharp `turning point' below which P-th increases with decreasing (n) over bar (e) is found for I-p/B-t values of 2.5 MA/2.7 T, 2.5 MA/2.6T 2.5 MA/2.4T and 2.2 MA/2.4T. The pedestal electron temperature demonstrates a very similar dependence on the edge (n) over tilde (e) as P-th. The role of Z(eff) in the variation of the H-mode power threshold with density is also considered. Shots with the divertor septum present are compared with an identical (n) over bar (e) scan, run with the MkII GB septum replacement plate divertor at 2.5 MA/2.7 T and 2.5 MA/2.6 T. The results from this investigation indicate that removal of the septum may have lowered the (n) over tilde (e) `turning point' for P-th.

Published
2006
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28. Development of internal transport barrier scenarios at ITER-relevant high triangularity in JET

Author

M.R. de Baar, E. de la Luna, Efda-Jet Contributors, P. J. Lomas, A. Ekedahl, G. Saibene, P. de Vries, F. Crisanti, G. T. A. Huysmans, F.G. Rimini, X. Litaudon, Angelo A. Tuccillo, O. Tudisco, E. Giovannozzi, B. Alper, N. C. Hawkes, Vassili Parail, K.-D. Zastrow, and M. Becoulet

Subjects
Nuclear and High Energy Physics, Jet (fluid), Tokamak, Materials science, chemistry.chemical_element, Radius, Plasma, Edge (geometry), Condensed Matter Physics, Computational physics, law.invention, Neon, Pedestal, chemistry, law, Atomic physics, Edge-localized mode
Abstract

The development of scenarios characterized by H-mode confinement and internal transport barriers (ITBs) in high triangularity, δ ~ 0.4–0.5, discharges is of particular interest for ITER advanced tokamak operation. Previous JET experiments have shown that high triangularity favours H-modes which are ELM-free or develop type I edge localized mode (ELM) activity, which inhibits long lasting ITBs. The recent experiments reported here concentrate on integrated optimization of edge and core conditions. The stability of the edge pedestal was controlled using gas injection, deuterium or light impurities, and plasma current ramps. Both methods yield more ITB-friendly edge pedestal conditions, varying from small type I to type III ELMs and, in extreme cases, resulting in L-mode. In parallel, the conditions for triggering and sustaining ITBs encompassing a large proportion of the plasma volume (outer ITBs) were optimized, as opposed to less performing ITBs located closer to the plasma centre (inner ITB). These plasmas have deeply reversed target current profiles with qmin ~ 3 and a narrow inner ITB, located typically at a small normalized radius ρ < 0.5 and close to the reversed shear region, is routinely observed. Large radius outer ITBs are only triggered at an input power in excess of 20 MW, but they do not usually survive the transition into H-mode. The best results, in terms of sustained high confinement, have been obtained with neon injection; an outer ITB is triggered during the phase with L-mode edge and survives into H-mode for about 2 s, corresponding to ~10 times the global energy confinement time τE, at q95 = 7.5, H89βN ~ 3.5–4 and ~60% of the Greenwald density limit. In summary, a high triangularity scenario has been developed, which combines the desirable characteristics of controlled edge, long lasting wide ITBs and high performance at density higher than the low triangularity JET scenarios.

Published
2005
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29. Real-time measurement and control at JET experiment control

Author

R. Bridge, S. Griph, A.V. Stephen, I.D. Young, Tommaso Bolzonella, K.-D. Zastrow, C. Ingesson, P. Card, M. Beldishevski, N. C. Hawkes, F. Piccolo, M. D. J. Bright, Jacques Blum, Paolo Innocente, Diogo Alves, D. F. Howell, J. Davis, E. Vitale, J.W. Farthing, S. Popovichef, A. Huber, R. C. Felton, R. Barnsley, Luca Zabeo, Oliviero Barana, E. Joffrin, P. Heesterman, O. Hemming, J. Harling, Javier Sánchez, F. Crisanti, H. Leggate, C. H. A. Hogben, I. Coffey, T. Budd, G. Lloyd, C. Gowers, Filippo Sartori, Marco Valisa, M. Buckley, P. McCullen, E. Jones, D. Moreau, S. E. Dorling, M. Zerbini, K. Guenther, João M. C. Sousa, Didier Mazon, M. Walters, A. Goodyear, Andrea Murari, R. Lucock, C. Giroud, K. Bosak, S. Dalley, M. Stamp, M. Wheatley, Marco Riva, E. de la Luna, and T. Edlington

Subjects
Physics, Tokamak, Mechanical Engineering, Nuclear engineering, Divertor, Plasma, ITER-relevant, Neutral beam injection, law.invention, Nuclear magnetic resonance, Nuclear Energy and Engineering, Physics::Plasma Physics, JET, Control theory, law, Control system, General Materials Science, Plasma diagnostics, Interlock, Real-time, Civil and Structural Engineering
Abstract

Over the past few years, the preparation of ITER-relevant plasma scenarios has been the main focus of experimental activity on tokamaks. The development of integrated, simultaneous, real-time controls of plasma shape, current, pressure, temperature, radiation, neutron profiles and also impurities, ELMs and MHD are now seen to be essential for further development of quasi-steady state conditions with feedback, or the stabilisation of transient phenomena with event-driven actions. For this thrust, the EFDA JET Real-Time Project has developed a set of real-time plasma measurements, experiment control and communication facilities. The plasma diagnostics used for real-time experiments are Far Infra Red interferometry, polarimetry, visible, UV and X-ray spectroscopy, LIDAR, bolometry, neutron and magnetics. Further analysis systems produce integrated results, such as temperature profiles on geometry derived from MHD equilibrium solutions. The actuators include toroidal, poloidal and divertor coils, gas and pellet fuelling, neutral beam injection, radio frequency (ICRH) waves and microwaves (LH). The heating/fuelling operators can either define a power or gas request waveform or select the real-time instantaneous power/gas request from the real-time experiment central control (RTCC) system. The real-time experiment control system provides both a high-level, control-programming environment and interlocks with the actuators. A MATLAB facility is being developed for the development of more complex controllers. The plasma measurement, controller and plant control systems communicate in ATM network. The EFDA Real-Time Project is essential groundwork for future reactors such as ITER. It involves many staff from several institutions. The facility is now frequently used in experiments. This work has been conducted under the European Fusion Development Agreement and is partly funded by Euratom and the UK Engineering and Physical Sciences Research Council.

Published
2005
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30. New millimeter-wave access for JET reflectometry and ECE

Author

A. J. H. Donne, L. Meneses, C. Antonucci, Garrard Conway, L. Cupido, A. Guigon, Alessandro Bruschi, F. J. van Amerongen, J. M. Chareau, Carlo Sozzi, E. Manso, D. Starky, W.A. Bongers, J. Fessey, D. Sands, M. F. Graswinckel, D. Wagner, V. Ricardo, E. de la Luna, A. Simonetto, S. Cirant, Filipe da Silva, S. Hanks, P. Varela, T. Tisconia, N. Balshaw, and R. Pearce

Subjects
Reflectometry, Jet (fluid), Electron density, Materials science, business.industry, Thomson scattering, Mechanical Engineering, Millimeter-wave, Fusion power, Temperature measurement, Optics, Nuclear Energy and Engineering, Physics::Plasma Physics, Extremely high frequency, Corrugated waveguide, General Materials Science, Antenna (radio), business, Civil and Structural Engineering
Abstract

Millimeter-wave diagnostics at JET, mainly reflectometry, are employing state of art electronics, but are limited in performance by the existing waveguides and antenna system that are inadequate and obsolete. The use of long run waveguides with high losses and non-optimized antennas (in some cases, not pointing to relevant plasma positions) lead to difficult measurement conditions for reflectometry. The new access system presented in this article has been designed to improve the performance of reflectometry measurements and enable the installation of antennas for oblique viewing ECE. These two new antennae will allow the ECE radiation to be collected at different angles with respect to the magnetic field. This set-up, known as oblique ECE [1] , is expected to be extremely useful in improving the interpretation of ECE temperature measurements in all fusion experiments with significant additional heating. For reflectometry, there is an urgent need to improve the edge density measurements as both the lithium beam and Thomson scattering exhibit limitations of resolution at lower densities. The project proposal states that the expected improvement in reflectometry S/N ratio is 30 dB. If realized, this will allow broad band reflectometry, for the measurement of the electron density profile, for the first time in JET.

Published
2005
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31. Effect of sawtooth activity on tritium and beam deuterium evolution in trace tritium experiments on JET

Author

D. C. McDonald, Jet-Efda Contributors, Sergey Popovichev, Xavier Garbet, K.-D. Zastrow, E. de la Luna, B. Alper, D. C. McCune, I. Voitsekhovitch, V. G. Kiptily, G. Bonheure, S. E. Sharapov, and D. Stork

Subjects
Materials science, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Plasma, Sawtooth wave, Condensed Matter Physics, Nuclear physics, Nuclear Energy and Engineering, Deuterium, Physics::Plasma Physics, Physics::Accelerator Physics, Electron temperature, Neutron, Tritium, Plasma diagnostics, Atomic physics
Abstract

One of the scenarios actively studied during the 2003 trace tritium experimental campaign performed on JET includes a gas puff of small amounts of tritium into sawtooth-unstable H-mode plasmas heated by deuterium beams. The sawtooth crashes observed in these discharges, with the electron cyclotron emission diagnostics, are frequently accompanied by the oscillations of the 14 MeV neutron emission, produced mainly due to the reaction between the deuterium beam and the thermal tritium. Such oscillations are clearly seen in low density plasmas while they are weak or absent at high density. The goal of this work is to explain the different behaviour of the oscillations of neutron emission with density. For this purpose, the dynamics of the trace tritium and beam deuterium during the sawtooth crash in discharges with different plasma density is studied numerically using the TRANSP code. In addition, a possibility of using the neutron measurements in sawtoothing low density plasmas for the test of the full and partial reconnection models is discussed and the sensitivity of the simulations to the key parameters of these models is presented.

Published
2005
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32. On the use of MHD mode analysis as a technique for determination of q-profiles in JET plasmas

Author

P. Smeulders, C. D. Challis, E. de la Luna, J. Mailloux, B. Alper, N. C. Hawkes, M. F. F. Nave, S.N. Gerasimov, S. Hacquin, C. Boswell, S. E. Sharapov, M. Brix, R. Galvão, D. N. Borba, Efda-Jet Contributors, and E. Joffrin

Subjects
Physics, Jet (fluid), Cross-correlation, Plasma, Low frequency, Computational physics, Physics::Plasma Physics, Normal mode, Physics::Space Physics, ddc:530, Pickup, Plasma diagnostics, Atomic physics, Magnetohydrodynamics, Instrumentation
Abstract

JET plasmas show fluctuations from a large variety of MHD instabilities. A combination of spectral analysis, mode number analysis, and determination of mode radial position has the potential as a diagnostic for the plasma q profile. Mode frequencies and mode numbers are obtained from spectral and phase analysis from fast magnetic pickup signals. Cross correlation of magnetic and multiarray signals from ECE, SXR, and reflectometer systems provide the mode localization. The present status of the diagnostic systems used for fluctuation analysis is summarized, with particular emphasis on the fast magnetic pickup system. A new data collection system allows the magnetic signals to be recorded at 2 MHz for up to 32 s in each pulse. An example of q-profile validation from the observation of Alfven eigenmode cascades and a snake is given. At JET, Alfven cascades are used to determine q(min) in optimized shear discharges, while a variety of low frequency modes (such as the snake) allow the determination of the radial position of q integer values in monotonic and reversed shear q profiles. (C) 2004 American Institute of Physics.

Published
2004
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33. Characterization of pedestal parameters and edge localized mode energy losses in the Joint European Torus and predictions for the International Thermonuclear Experimental Reactor

Author

A. Loarte, G. Saibene, R. Sartori, T. Eich, A. Kallenbach, W. Suttrop, M. Kempenaars, M. Beurskens, M. de Baar, J. Lönnroth, P. J. Lomas, G. Matthews, W. Fundamenski, V. Parail, M. Becoulet, P. Monier-Garbet, E. de la Luna, B. Gonçalves, C. Silva, Y. Corre, and null Contributors to the EFDA-JET Workpr

Subjects
Nuclear physics, Physics, Thermonuclear fusion, Physics::Plasma Physics, Divertor, Joint European Torus, Plasma, Mechanics, Collisionality, Condensed Matter Physics, Kinetic energy, Edge-localized mode, Instability
Abstract

This paper presents the experimental characterization of pedestal parameters, edge localized mode (ELM) energy, and particle losses from the main plasma and the corresponding ELM energy fluxes on plasma facing components for a series of dedicated experiments in the Joint European Torus (JET). From these experiments, it is demonstrated that the simple hypothesis relating the peeling-ballooning linear instability to ELM energy losses is not valid. Contrary to previous observations at lower triangularities, small energy losses at low collisionality have been obtained in regimes at high plasma triangularity and q95∼4.5, indicating that the edge plasma magnetohydrodynamic stability is linked with the transport mechanisms that lead to the loss of energy by conduction during type I ELMs. Measurements of the ELM energy fluxes on the divertor target show that their time scale is linked to the ion transport along the field and the formation of a high energy sheath, in agreement with kinetic modeling of ELMs. Higher...

Published
2004
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34. Impact of bulk non-Maxwellian electrons on electron temperature measurements (invited)

Author

V. Krivenski, E. de la Luna, M. Zerbini, J. M. Travere, R. Prentice, C. Gowers, and G. Giruzzi

Subjects
Physics, Thomson scattering, Cyclotron, Plasma, Electron, Neutral beam injection, law.invention, Physics::Plasma Physics, law, Electron temperature, Plasma diagnostics, Atomic physics, Instrumentation, Ion cyclotron resonance
Abstract

In neutral beam injection and ion cyclotron resonance frequency (NBI+ICRF) heated high-temperature Joint European Torus (JET) plasmas, electron cyclotron emission (ECE) spectra measured by the Michelson interferometer are inconsistent with the electron bulk distribution being Maxwellian. This conclusion follows from new, accurate modeling of the ECE spectra over the full measured frequency range, covering the first four harmonics of the cyclotron frequency. A model distribution function obtained by fitting a measured ECE spectrum reveals a distortion of the Maxwellian that is sharply localized at ∼1.5×thermal momentum. A consequence deduced from this distribution is that the electron temperature measured by JET’s Thomson scattering diagnostic, which weighs the bulk electrons differently, should be lower than the ECE one in the spatial region where this distortion exists. This prediction appears to be confirmed by temperature profile comparisons showing that core Thomson scattering electron temperatures on JET are up to 20% lower than ECE values for plasmas with strong NBI+ICRF heating. The possibility of addressing experimentally the question of whether the plasma has a Maxwellian bulk is also discussed. This goal can be accomplished by observing the emission at different angles with respect to the magnetic field (oblique ECE). Simulations of oblique ECE spectra using the model distribution function obtained previously show an angular variation of the emission that is characteristic of the distorted bulk.

Published
2003
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35. Coupled core-SOL modelling of W contamination in H-mode JET plasmas with ITER-like wall

Author

Tuomas Koskela, E. Militello-Asp, M. Tsalas, M. Romanelli, F. Koechl, P. C. da Silva Aresta Belo, G. Corrigan, D. Harting, E. de la Luna, V.V. Parail, Jet-Efda Contributors, and A. G. Meigs

Subjects
Nuclear and High Energy Physics, Chemistry, Divertor, chemistry.chemical_element, Plasma, Transport barrier, Tungsten, 01 natural sciences, 010305 fluids & plasmas, Nuclear Energy and Engineering, Impurity, Sputtering, 0103 physical sciences, Pinch, General Materials Science, Atomic physics, 010306 general physics, Plasma density
Abstract

The influence of the ITER-like Wall (ILW) with divertor target plate made of tungsten (W), on plasma performance in JET H-mode is being investigated since 2011 (see F. Romanelli and references therein). One of the key issues in discharges with low level of D fuelling is observed accumulation of W in the plasma core, which leads to a reduction in plasma performance. To study the interplay between W sputtering on the target plate, penetration of W through the SOL and edge transport barrier (ETB) and its further accumulation in plasma core predictive modelling was launched using a coupled 1.5D core and 2D SOL code JINTRAC (Romanelli, 2014; Cenacchi and Taroni, 1988; Taroni et al., 1992; Wiesen et al., 2006). Simulations reveal the important role of ELMs in W sputtering and plasma density control. Analyses also confirm pivotal role played by the neo-classical pinch of heavy impurities within the ETB.

Published
2015
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36. Tungsten transport and sources control in JET ITER-like wall H-mode plasmas

Author

E. Joffrin, C. F. Maggi, Isabel L. Nunes, M. Tsalas, G. Maddison, G. F. Matthews, Nicolas Fedorczak, E. de la Luna, Jet-Efda Contributors, Bruce Lipschultz, P. Devynck, E. R. Solano, F. Rimini, S. Brezinsek, P. Monier-Garbet, Th. Pütterich, R. J. Dumont, P. de Vries, Patrick Tamain, E. Lerche, M. Goniche, and JET-EFDA Contributors

Subjects
Nuclear and High Energy Physics, Electron density, Jet (fluid), Divertor, Cyclotron, chemistry.chemical_element, Plasma, Tungsten, 7. Clean energy, law.invention, Nuclear Energy and Engineering, chemistry, law, Dielectric heating, General Materials Science, Beryllium, Atomic physics
Abstract

A set of discharges performed with the JET ITER-like wall is investigated with respect to control capabilities on tungsten sources and transport. In attached divertor regimes, increasing fueling by gas puff results in higher divertor recycling ion flux, lower divertor tungsten source, higher ELM frequency and lower core plasma radiation, dominated by tungsten ions. Both pedestal flushing by ELMs and divertor screening (including redeposition) are possibly responsible. For specific scenarios, kicks in plasma vertical position can be employed to increase the ELM frequency, which results in slightly lower core radiation. The application of ion cyclotron radio frequency heating at the very center of the plasma is efficient to increase the core electron temperature gradient and flatten electron density profile, resulting in a significantly lower central tungsten peaking. Beryllium evaporation in the main chamber did not reduce the local divertor tungsten source whereas core radiation was reduced by approximately 50%.

Published
2015
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37. Review of confinement and transport studies in the TJ-II flexible heliac

Author

A. Salas, P. Méndez, E. Ascasíbar, Javier Alonso, Macarena Liniers, L Almoguera, Jesús Vega, Angela Garcia, Romualdo Martín, J. A. Jiménez, Victor Tribaldos, Beatriz Brañas, R. Carrasco, J. Qin, Francisco Castejón, A. Portas, D. Tafalla, A. de la Peña, M. Medrano, B. Zurro, E. de la Luna, C. Fuentes, M. A. Ochando, J. Castellano, F. Medina, M. A. Pedrosa, Isabel García-Cortés, M Blaumoser, J Doncel, J. Botija, I. Kirpitchev, E. Sánchez, J. Sánchez, L. Rodríguez-Rodrigo, Francisco L. Tabarés, J. Guasp, A. López-Sánchez, S. Eguilior, A. Baciero, F. Lapayese, K. Likin, C. Hidalgo, I. Labrador, T. Estrada, C. Alejaldre, A. López-Fraguas, J. Herranz, B. van Milligen, V. Krivenski, E. de la Cal, Asunción Fernández, C Cremy, J.A. Romero, Luis F. Pacios, I. Pastor, K. J. McCarthy, R. Balbín, A. Cappa, L. Martínez-Laso, and J.R. Cepero

Subjects
Physics, Coupling, Nuclear and High Energy Physics, Hydrogen, chemistry.chemical_element, Plasma, Condensed Matter Physics, law.invention, Shear (sheet metal), Electric power transmission, Nuclear magnetic resonance, chemistry, law, Atomic physics, Transport studies, Helium, Stellarator
Abstract

TJ-II is a four period, low magnetic shear stellarator (R = 1.5 m, a < 0.22 m, B0 ≤ 1.2 T) which was designed to have a high degree of magnetic configuration flexibility. In the most recent experimental campaign, coupling of the full ECRH power (PECRH ≤ 600 kW) to the plasma has been possible using two ECRH transmission lines which have different power densities. Both helium and hydrogen fuelled plasmas have been investigated. The article reviews the latest physics results in particle control, configuration effects, and transport and fluctuation studies.

Published
2001
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38. Multichannel electron cyclotron emission radiometry in TJ-II stellarator

Author

Victor Tribaldos, T. Estrada, J. Sánchez, and E. de la Luna

Subjects
Physics, Heterodyne, Radiometer, business.industry, Cyclotron, Bolometer, law.invention, Optics, law, Radiometry, Plasma diagnostics, Heterodyne detection, business, Instrumentation, Stellarator
Abstract

Electron cyclotron emission measurements are routinely performed in TJ-II stellarator by means of a multichannel heterodyne radiometer. The radiometer is absolutely calibrated and measures the temperature profile with high temporal resolution. The description of the radiometer, the calibration procedure, and some data taken during the occurrence of fast phenomena in the plasma (edge localized mode-like events and central temperature crashes) are presented in the article.

Published
2001
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39. Edge-localized-mode-like events in the TJ-II stellarator

Author

Enrique Ascasibar, S.V. Shchepetov, J.A. Jiménez, Francisco L. Tabarés, T. Estrada, D. Tafalla, J. Qin, A. López-Fraguas, B. Zurro, J. Sanchez, E. de la Luna, J. Herranz, I. Pastor, Victor Tribaldos, Francisco Castejón, I. García-Cortés, Tj-Ii Team, and B. Brañas

Subjects
Physics, Nuclear and High Energy Physics, Electron, Radius, Plasma, Condensed Matter Physics, Instability, Flattening, law.invention, Physics::Plasma Physics, law, Electron temperature, Atomic physics, Edge-localized mode, Stellarator
Abstract

ELM-like activity has been recently observed in TJ-II, in plasmas with stored energy above 1 kJ. The plasma is observed to develop bursts of magnetic activity (seen in Mirnov coil signals) which are followed by a large and distinct spike in the Hα signal. An increase in electrostatic and magnetic fluctuations at the plasma edge and a cold pulse towards the plasma centre are also characteristics of these events. In addition, the electron temperature profile locally flattens at the plasma radius where the temperature is in the range 100-200 eV. This flattening can be explained in terms of enhanced electron heat conductivity. Between ELM-like events the electromagnetic turbulence at the edge decreases and the Te profiles recover their former shapes. This activity is probably triggered by a resonant m = 2, n = 3 mode.

Published
2000
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40. Two-dimensional effects of turbulence in density profile measurements by reflectometry

Author

V. Zhuravlev, E. de la Luna, and J. Sanchez

Subjects
Physics, Turbulence, Scattering, business.industry, Plasma, Condensed Matter Physics, WKB approximation, Computational physics, Amplitude modulation, Wavelength, Optics, Nuclear Energy and Engineering, Physics::Plasma Physics, Plasma diagnostics, Reflectometry, business
Abstract

Reflectometry is a very attractive diagnostic for measurements of density profile and plasma turbulence in reactor conditions, but the problem of interpretation of the results is not solved utterly. The reason for this is the plasma turbulence which leads to interference of signals, reflected simultaneously on different turbulent waves and back scattering of signal. Other source of perturbations is the multiple reflection of the signal between plasma and chamber wall. These effects can be simulated completely only in a 3-d full-wave code, though simulation of effects of scattering and interference may be reduced to 2-d taking advantage of the homogeneity of the plasma in the toroidal direction. Full-wave 2-d codes have been developed in recent time 1, but the use of this codes is limited due to the very complicated computations involved (a realistic simulation of a density profile measurement involves typically the calculation of the E-field detected at the antenna for a set of 2000 frequency values). In this work, a simple WKB 2-d code was used for qualitative simulation of effects of interference in situations where the turbulence size is larger than the signal wavelength.

Published
1996
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41. Electron cyclotron emission radiometer upgrade on the Joint European Torus (JET) tokamak

Author

J. Fessey, J. Sanchez, R. Prentice, G. Conway, C. Gowers, W. Suttrop, Jet Efda contributors, Victor Tribaldos, E. de la Luna, and J. M. Chareau

Subjects
Physics, Jet (fluid), Tokamak, Radiometer, business.industry, Joint European Torus, Cyclotron, law.invention, Optics, law, Electron temperature, High Energy Physics::Experiment, Plasma diagnostics, Spectral resolution, Atomic physics, business, Instrumentation
Abstract

The capabilities of the Joint European Torus (JET) electron cyclotron emission (ECE) diagnostics have recently been extended with an upgrading of the heterodyne radiometer. The number of channels has been doubled to 96 channels, with a frequency separation corresponding to 2.6 m for the X-mode due to harmonic overlap) at almost all magnetic field values used at JET (1.7 T

Published
2004
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42. Edge density profile measurements by amplitude modulation reflectometry on PBX-M tokamak

Author

R. Kaita, M. Ono, J. Sánchez, V. Zhuravlev, G. R. Hanson, John B Wilgen, and E. de la Luna

Subjects
Electron density, Tokamak, Materials science, Thomson scattering, business.industry, Condensed Matter Physics, law.invention, Amplitude modulation, Optics, Nuclear Energy and Engineering, law, Plasma diagnostics, business, Reflectometry, Microwave, Group delay and phase delay
Abstract

A reflectometer, based on the amplitude modulation technique, has been developed and operated on a PBX-M for the measurement of electron density profile. The system, operating with the extraordinary mode in the range of 32-50 GHz, is able to measure the density profile in the plasma edge from the scrape-off layer up to typically r/a=0.7. The determination of the time delay for each frequency is achieved by measuring the phase delay of a 200 MHz amplitude modulation envelope superimposed on the millimetre wave probing signal. The system has a final bandwidth of 40 kHz and is able to obtain the edge profile during a 1 ms sweep of the microwave source. High quality profiles are obtained in systematic good agreement with Thomson scattering measurements. The profile reconstruction from the raw data is direct, with only a need for minimal data processing. Profiles have been measured for ohmic, RF and NBI heated discharges. Features of the profile changes in the kH transition are shown. One of the goals of the instrument has been the measurement of the slight modifications to the edge density profile produced by the injection of ion Bernstein waves. These changes have been clearly observed and are in agreement with theoretical expectations.

Published
1995
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43. Swept frequency reflectometer for correlation studies in the TJ‐I tokamak

Author

T. Estrada, Beatriz Brañas, E. de la Luna, and J. Sánchez

Subjects
Maxima and minima, Physics, Optics, Homodyne detection, business.industry, Turbulence, Plasma diagnostics, Radius, business, Maxima, Instrumentation, Differential phase, Coherence (physics)
Abstract

An improved correlation reflectometer technique has been developed and implemented on TJ‐I to measure the radial correlation lengths of the density turbulence. The method uses homodyne detection and is based on the slow sweeping of one oscillator while the other remains at fixed frequency. The decay of the coherence shows maxima and minima as the distance between the two probing points increases. The maxima correspond to the relevant coherence values. The correlation length for the overall turbulence as well as the correlation length for the different frequency intervals can be directly determined in a single shot. By the operation in the Q‐band (33–50 GHz) extraordinary mode, the system reaches most of the plasma radius. Correlation lengths obtained at the edge are compared with those measured at deeper positions in the plasma. The proposed method can provide the values of the differential phase delay along the sweep, avoiding the effect of lost fringes even in the presence of turbulence. This opens the possibility of obtaining the information on the density profile if several channels are used.

Published
1993
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44. Electrostatic and magnetic fluctuations in the proximity of the velocity shear layer in the TJ‐I tokamak

Author

Beatriz Brañas, J. Sánchez, E. de la Luna, M. A. Pedrosa, T. Estrada, R. Balbín, Isabel García-Cortés, C. Hidalgo, and A. P. Navarro

Subjects
Fluid Flow and Transfer Processes, Physics, Tokamak, Condensed matter physics, Turbulence, Computational Mechanics, General Physics and Astronomy, Magnetic confinement fusion, Plasma, Condensed Matter Physics, Magnetic field, law.invention, Physics::Fluid Dynamics, Shear (sheet metal), symbols.namesake, Physics::Plasma Physics, Mechanics of Materials, law, Electric field, symbols, Langmuir probe
Abstract

The structure of the electrostatic and magnetic turbulence changes in the proximity of the naturally occurring velocity shear layer in the TJ‐I tokamak [Nucl. Fusion 30, 717 (1990)]. Both a modification in the fluctuation levels and autocorrelation times of the Langmuir probe ion saturation current and a decorrelation in the broadband magnetic fluctuations, have been observed in the proximity of the shear layer location. However, no direct correlation between the sheared poloidal flows and turbulence characteristics has been established.

Published
1992
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45. First applications of structural pattern recognition methods to the investigation of specific physical phenomena at JET

Author

N. Duro, A. Pereira, Matilde Santos, E. de la Luna, A. Murari, Gonzalo Farias, Raquel Dormido, A. Portas, Jesús Vega, Gonzalo Pajares, Hector Vargas, Sebastián Dormido-Canto, G.A. Rattá, and J. Sánchez

Subjects
Structure (mathematical logic), Jet (fluid), business.industry, Computer science, Mechanical Engineering, Access method, Pattern recognition, Domain (software engineering), Identification (information), Nuclear Energy and Engineering, Data retrieval, Pattern recognition (psychology), General Materials Science, Artificial intelligence, Explicit knowledge, business, Civil and Structural Engineering
Abstract

Structural pattern recognition techniques allow the identification of plasma behaviours. Physical properties are encoded in the morphological structure of signals. Intelligent access methods have been applied to JET databases to retrieve data according to physical criteria. On the one hand, the structural form of signals has been used to develop general purpose data retrieval systems to search for both similar entire waveforms and similar structural shapes inside waveforms. On the other hand, domain dependent knowledge was added to the structural information of signals to create particular data retrieval methods for specific physical phenomena. The inclusion of explicit knowledge assists in data analysis. The latter has been applied in JET to look for first, cut-offs in ECE heterodyne radiometer signals and, second, L-H transitions.

Published
2008
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46. First results with amplitude modulation reflectometry on the PBX‐M tokamak

Author

L. W. Schmitz, V. Zhuravlev, R. Kaita, G. R. Hanson, L. Blush, J.L. Dunlap, Isabel García-Cortés, J. Sánchez, George Tynan, E. de la Luna, John B Wilgen, B.P. LeBlanc, and J. H. Harris

Subjects
Electron density, Materials science, Tokamak, business.industry, Thomson scattering, law.invention, Amplitude modulation, Optics, law, Plasma diagnostics, Reflectometry, business, Instrumentation, Microwave, Group delay and phase delay
Abstract

Electron density profile measurements have been obtained on PBX‐M by amplitude modulation reflectometry. With this technique, the measurement of the time delay is obtained from the phase delay of the modulating envelope (200 MHz in PBX‐M). The system operates with the extraordinary mode, in the range 32–50 GHz. Under these conditions the density profile of PBX‐M can be probed from the scrape‐off layer up to typically r/a=0.7. With a final bandwidth of 40 kHz, the reflectometer is able to obtain the edge profile in 1 ms. The profiles obtained are relatively noise free and in good agreement with Thomson scattering measurements. Perturbations due to the strong‐edge turbulence are kept to a minimum, and no software filtering or other signal processing was necessary to extract the time delay information from the raw data. Profiles have been measured for ohmic and Neutron Beam Injection heated discharges.

Published
1995
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47. Amplitude modulation reflectometry for large fusion devices

Author

E. de la Luna, V. Zhuravlev, Beatriz Brañas, J. Sánchez, and T. Estrada

Subjects
Physics, Amplitude modulation, Amplitude, Optics, Modulation, business.industry, Phase (waves), Plasma diagnostics, business, Reflectometry, Instrumentation, Signal, Group delay and phase delay
Abstract

One of the main problems which arises in density profile measurements by reflectometry is the need for continuous tracking of the phase delay; fast density fluctuations and strong modulation on the amplitude of the reflected signal can cause ‘‘fringe jumps’’ in the phase signal. Amplitude modulation reflectometry performs a time delay measurement by the determination of the phase delay of the modulating envelope of a millimeter wave reflected by the plasma. The phase delays involved are small, the measurement is not affected by the fluctuations and can be directly performed without complicated fringe counters; the method provides a promising possibility for real time determination of the plasma position and density profile. In the present paper the principles of the method are presented as well as the analysis on the effects of phase and amplitude fluctuations, dispersive effects, and accuracy requirements.

Published
1992
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48. Neoclassical tearing mode (NTM) magnetic spectrum and magnetic coupling in JET tokamak

Author

P. de Vries, B. Alper, J. Mailloux, N. C. Hawkes, E. Joffrin, F. Crisanti, C. Giroud, D. F. Howell, X. Litaudon, O. Tudisco, M. Baruzzo, M. Brix, Frederic Imbeaux, A. C. C. Sips, P. Buratti, C. D. Challis, Jet-Efda Contributors, Tommaso Bolzonella, E. de la Luna, and H. R. Koslowski

Subjects
Physics, Jet (fluid), Toroid, Tokamak, Plasma parameters, Cyclotron, Electron, Plasma, Condensed Matter Physics, law.invention, Computational physics, Nuclear Energy and Engineering, Physics::Plasma Physics, law, Electron temperature, Atomic physics
Abstract

An experimental study on the poloidal mode number (m) spectrum produced by a single toroidal mode number (n) neoclassical tearing mode (NTM) in the JET tokamak is presented. Clear evidence of the existence of more than one significant m component is given. The analysis is performed comparing several methods and diagnostics; among the latter we mention high frequency magnetic pick-up coils and an electron cyclotron emission radiometer, which measures detailed electron temperature radial profiles at high time resolution. The two diagnostics are also used together in a cross coherence calculation technique. The issue of the interaction of this multiple m structure with the plasma is addressed as well, with particular attention paid to plasma toroidal rotation and rotation shear, obtained from charge exchange spectroscopy data. This effect has been studied under two different operational plasma scenarios on JET in order to investigate both dependences on plasma parameters and consequences on the scenario itself.

Published
2010
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49. Tracking magnetic resonances in the effective electron heat diffusivity of ECH plasmas of the TJ-II Heliac

Author

V. I. Vargas, Francisco Castejón, T. Estrada, Enrique Ascasibar, F. Medina, D. López-Bruna, E. de la Luna, and J.A. Romero

Subjects
Physics, Toroid, Cyclotron, General Physics and Astronomy, Magnetic confinement fusion, Plasma, Electron, Collisionality, Thermal diffusivity, law.invention, Shear (sheet metal), Physics::Plasma Physics, law, Atomic physics
Abstract

Low order rational numbers of the rotational transform (magnetic resonances, in short) have been considered deleterious for magnetic confinement in toroidal devices. The design and operation of stellarators has been based on the notion that either the resonances should be relegated to small volumes with high magnetic shear, or they had to be simply avoided. Low density, low collisionality discharges of the low magnetic shear TJ-II device show that these resonances can benefit electron heat confinement. Only in conditions of very low shear over an extended radial portion of the plasma, do the resonances have a detrimental effect on confinement. The experiments consist of Electron Cyclotron Heated (ECH) plasmas where a moderated Ohmic current is induced. A distinctive feature of the TJ-II Heliac is its high rotational transform.

Published
2008
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50. New diagnostic techniques and technologies at JET (invited)

Author

H. G. Esser, S. Hacquin, B. Alper, Göran Ericsson, J. Kaellne, S. E. Sharapov, M. G. O'Mullane, P. Coad, K.-D. Zastrow, V. Philipps, J. Brzozowski, A. Murari, V. G. Kiptily, Luciano Bertalot, E. de la Luna, Sean Conroy, K. D. Lawson, and Jet-Efda Contributors

Subjects
Physics, Jet (fluid), Spectrometer, Divertor, Nuclear engineering, Detector, Interferometry, Time of flight, Physics::Plasma Physics, ddc:530, Neutron, Plasma diagnostics, Atomic physics, Instrumentation
Abstract

The European Fusion Development Agreement's mission for JET is the development of ITER scenarios exploiting the specific properties of the device. This task requires significant improvements in the measuring techniques. The most innovative diagnostic upgrades are in the fields of edge measurements, detection of fast magnetohydrodynamics modes and "burning plasma" diagnostics. The importance of plasma-wall interactions, and, in particular, the issue of tritium inventory promoted the development of the quartz microbalance, a detector with improved time resolution to measure material redeposition in the remote areas of the inner divertor. Measurement of Alfven cascades with unprecedented spectral resolution, reaching a toroidal n number of up to 16, was obtained using an O-mode microwave reflectometer as an interferometer. For the diagnosis of the fusion products, a new approach is being developed to measure the He ash based on double charge exchange between thermalized particles and neutrals from JET beams. There have been several upgrades of the neutron diagnostic systems, one of which, the new time of flight neutron spectrometer designed for high counting rates is described. (c) 2006 American Institute of Physics.

Published
2006
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