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1. Recent progress of JT-60SA project toward plasma operation

Author

H. Shirai, K. Takahashi, E. Di Pietro, D. Abate, W. Abdel Maksoud, H. Abe, N. Aiba, T. Abe, M. Akimitsu, J. Ayllon-Guerola, T. Arai, J.-F. Artaud, N. Asakura, N. Ashikawa, L. Balbinot, P. Barabaschi, O. Baulaigue, E. Belonohy, A. Belpane, W. Bin, F. Bombarda, T. Bolzonella, F. Bonne, M. Bonotto, J. Botija, J. Buermans, S. Cabrera-Pérez, A. Cardella, D. Carralero, L. Carraro, J. Cavalier, M. Cavinato, M. Chernyshova, S. Chiba, S. Clement-Lorenzo, V. Cocilovo, S. Coda, R. Coelho, I. Coffey, B. Collin, V. Corato, A. Cucchiaro, T. Czarski, M. Dairaku, S. Davis, C. Day, E. Dela Luna, G. De Tommasi, P. Decool, L. Di Pace, M. Dibon, G. Disset, F. D’Lsa, A. Ejiri, Y. Endo, N. Ezumi, G. Falchetto, A. Fassina, P. Fejoz, A. Ferro, W. Fietz, L. Figini, T. Fornal, G. Frello, T. Fujita, T. Fukuda, K. Fukui, M. Fukumoto, H. Funaba, M. Furukawa, S. Futatani, L. Gabellieri, E. Gaio, K. Galazka, J. Garcia, J. Garcia-Dominguez, J. Garcia-Lopez, M. Garcia-Munoz, L. Garzotti, F. Gasparini, S. Gharafi, L. Giacomelli, G. Ginoulhiac, G. Giruzzi, L. Giudicotti, J. Gonzalez-Martin, R. Guillén-González, N. Hajnal, S. Hall, K. Hamada, K. Hanada, M. Hanada, K. Hasegawa, S. Hatakeyama, V. Hauer, N. Hayashi, T. Hayashi, R. Heller, J. Hidalgo-Salaverri, S. Higashijima, J. Hinata, S. Hiranai, J. Hiratsuka, R. Hiwatari, C. Hoa, H. Homma, A. Honda, M. Honda, K. Hoshino, H. Hurzlmeier, M. Iafrati, K. Ibano, H. Ichige, M. Ichikawa, M. Ichimura, K. Ida, S. Ide, H. Idei, M. Iguchi, T. Iijima, S. Iio, R. Ikeda, Y. Ikeda, T. Imai, R. Imazawa, S. Inagaki, M. Inomoto, S. Inoue, A. Isayama, S. Ishida, Y. Ishii, M. Isobe, F. Janky, E. Joffrin, A. Jokinen, S. Kado, S. Kajita, K. Kajiwara, Y. Kamada, I. Kamata, A. Kaminaga, K. Kamiya, D. Kanapienyte, Y. Kashiwa, M. Kashiwagi, K. Katayama, Y. Kawamata, G. Kawamura, K. Kawano, Y. Kazakov, K. Kimura, F. Kin, M. Kisaki, S. Kitajima, K. Kiyono, K. Kizu, Y. Ko, K. Kobayashi, M. Kobayashi, S. Kobayashi, Ta. Kobayashi, To. Kobayashi, G. Kocsis, A. Kojima, S. Kokusen, M. Komata, K. Komuro, S. Konishi, A. Kovacsik, I. Ksiazek, M. Kubkowska, G. Kühner, M. Kuramochi, K. Kurihara, T. Kurki-Suonio, A.B. Kurniawan, T. Kuwata, B. Lacroix, V. Lamaison, A. Lampasi, P. Lang, P. Lauber, K. Lawson, Q. LeCoz, A. Louzguiti, R. Maekawa, T. Maekawa, S. Maeyama, G. Maffia, P. Maget, J. Mailloux, I. Maione, A. Maistrello, K. Malinowski, A. Mancini, G. Marchiori, J.-L. Marechal, V. Massaut, S. Masuzaki, R. Matoike, G. Matsunaga, S. Matsunaga, A. Matsuyama, Ch Mayri, M. Mattei, M. Medrano, A. Mele, I. Meyer, F. Michel, T. Minami, Y. Miyata, J. Miyazawa, Y. Miyo, T. Mizuuchi, K. Mogaki, J. Morales, P. Moreau, T. Morisaki, S. Morishima, S. Moriyama, A. Moro, H. Murakami, M. Murayama, S. Murakami, K. Nagasaki, O. Naito, N. Nakamura, S. Nakamura, T. Nakano, Y. Nakashima, V. Nardino, E. Narita, Y. Narushima, K. Natsume, S. Nemoto, R. Neu, S. Nicollet, M. Nishikawa, S. Nishimura, T. Nishitani, M. Nishiura, T. Nishiyama, M. Nocente, Y. Nobuta, L. Novello, F. Nunio, S. Ochoa, K. Ogawa, T. Ogawa, Y. Ogawa, S. Ohdachi, Y. Ohmori, N. Ohno, Y. Ohtani, K. Ohtsu, M. Ohzeki, T. Oishi, J. Okano, K. Okano, Y. Onishi, M. Osakabe, T. Oshima, V. Ostuni, A. Owada, M. Oya, Y. Oya, T. Ozeki, M.M. Parody Guzmán, R. Pasqualotto, S. Pelli, E. Perelli, E. Peretti, G. Phillips, C. Piccinni, L. Pigatto, A. Pironti, A. Pizzuto, B. Plöckl, G. Polli, J.-M. Poncet, P. Ponsot, G. Pucella, M. Puiatti, D. Radloff, V. Raimondi, F. Ramos, P. Rancsik, D. Ricci, S. Ricciarini, N. Richermoz, E. Rincon, A. Romano, P. Rossi, P. Roussel, G. Rubino, H. Saeki, A. Sagara, S. Sakakibara, H. Sakamoto, Miki Sakamoto, Mizu Sakamoto, Y. Sakamoto, A. Sakasai, S. Sakata, R. Sakurai, B. Salanon, A. Salmi, G. Sannazzaro, R. Sano, A. Sanpei, T. Sasajima, S. Sasaki, H. Sasao, F. Sato, M. Sato, T. Sato, M. Sawahata, A. Scherber, S. Scully, J. Segado-Fernandez, M. Seki, N. Seki, S. Seki, Y. Shibama, Y. Shibata, T. Shikama, K. Shimada, M. Shimono, J. Shinde, T. Shinya, K. Shinohara, J. Shiraishi, S. Soare, A. Soleto, Y. Someya, S. Sonoda, C. Sozzi, E. Streciwilk-Kowalska, H. Strobel, M. Sueoka, A. Sukegawa, S. Sumida, H. Suzuki, Ma Suzuki, Mi Suzuki, S. Suzuki, T. Suzuki, Y. Suzuki, J. Svoboda, T. Szabolics, T. Szepesi, Y. Takase, M. Takechi, K. Takeda, Y. Takeiri, H. Takenaga, C. Taliercio, N. Tamura, Hiro Tanaka, Hito Tanaka, K. Tanaka, Y. Tanaka, K. Tani, H. Tanigawa, M. Tardocchi, A. Terakado, M. Terakado, T. Terakado, B. Teuchner, B. Tilia, H. Tobari, H. Tobita, K. Tobita, K. Toi, N. Toida, H. Tojo, M. Tokitani, T. Tokuzawa, V. Tormarchio, M. Tomine, A. Torre, T. Totsuka, K. Tsuchiya, N. Tsujii, D. Tsuru, H. Tsutsui, M. Uchida, Y. Ueda, J. Uno, H. Urano, K. Usui, H. Utoh, M. Valisa, M. Vallar, R. Vallcorba-Carbonel, J.-C. Vallet, J. Varela, J. Vega, M. Verrecchia, L. Vieillard, F. Villone, P. Vincenzi, K. Wada, R. Wada, T. Wakatsuki, M. Wanner, F. Watanabe, K. Watanabe, S. Watanabe, T. Wauters, S. Wiesen, M. Wischmeier, M. Yagi, J. Yagyu, M. Yajima, S. Yamamoto, H. Yamanaka, K. Yamauchi, Y. Yamauchi, H. Yamazaki, K. Yamazaki, R. Yamazaki, S. Yamoto, S. Yanagi, K. Yanagihara, S. Yokooka, M. Yokoyama, T. Yokoyama, M. Yoshida, M. Yoshimura, N. Yoshizawa, K. Yuinawa, L. Zani, and P. Zito

Subjects
JT-60SA, superconducting tokamak, risk mitigation measures, integrated commissioning, maintenance and enhancement, international collaboration, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Superconducting (SC) tokamak JT-60SA plays an essential role in fusion research and development by supporting and complementing the ITER project, providing directions to the DEMO design activity and fostering next generation scientists and engineers. Since the short circuit incident at the terminal joints of equilibrium field coil #1 during the integrated commissioning (IC) in March 2021, both EU and JA implementing agencies (IAs) have examined how to ensure safe operation of JT-60SA by mitigating the risk of possible discharge occurrence inside the cryostat. Based on the experience of the global Paschen tests, the IAs have established a strategy of risk mitigation measures, which is a combination of (i) reinforcement of insulation, (ii) avoiding unnecessary voltage application to the coil systems and (iii) immediate de-energization of the coils when deteriorated vacuum conditions are detected. Thanks to the considerable efforts of the Integrated Project Team members, the IC restarted in May 2023. After confirmation of the SC state of the coil systems (TF, EF and CS), the coil energization test and the plasma operation phase 1 (OP-1) started. The first plasma was successfully achieved on 23 October 2023 with a limited value of voltage and current applied to the coils. The plasma configuration control was also confirmed with low plasma current and low auxiliary heating power conditions. Based on the IO–F4E–QST collaboration, activities of JT-60SA have been shared with the IO and provided an important lesson for ITER assembly and commissioning, and will provide an outstanding contribution to fusion research at large. After OP-1, maintenance & enhancement phase 1 (M/E-1) starts from January 2024, in which in-vessel components are installed, and heating and diagnostic systems are extensively upgraded to allow a high power heating experiment planned in OP-2. In order to make the best use of JT-60SA, a newly organized JT-60SA experiment team will refine the research plan for the future high heating power operation phase.

Published
2024
Full Text
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2. 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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3. 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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4. 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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5. The single crystal diamond-based diagnostic suite of the JET tokamak for 14 MeV neutron counting and spectroscopy measurements in DT plasmas

Author

D. Rigamonti, A. Dal Molin, A. Muraro, M. Rebai, L. Giacomelli, G. Gorini, M. Nocente, E. Perelli Cippo, S. Conroy, G. Ericsson, J. Eriksson, V. Kiptily, Z. Ghani, Ž. Štancar, M. Tardocchi, and JET Contributors

Subjects
nuclear diagnostics, neutron spectroscopy, single crystal diamond detectors, tokamaks, nuclear fusion diagnostics, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The Joint European Torus (JET) has recently conducted its second deuterium–tritium (DT) experimental campaign DTE2, providing unique opportunity for studying both physics and engineering aspects of nuclear fusion plasmas. This also allowed the exploitation of new diagnostics and technologies that were not available during the first JET DT campaign held in 1997. Among these new instruments, the enhancement projects of the JET nuclear diagnostics lead to the development and installation of synthetic single crystal diamond detectors along different collimated line of sights. This paper describes the single crystal diamond-based diagnostic suite of the JET tokamak and the enhanced 14 MeV neutron diagnostic capabilities in terms of neutron yield and high resolution neutron spectroscopy. The diamond characterization measurements and the calibration procedure at JET are shown, together with performance of the diamond based neutron spectrometer as 14 MeV neutron yield monitor which allows the separation of 2.5 MeV and 14 MeV neutrons in trace tritium plasmas. The first high-resolution 14 MeV neutron spectroscopy measurements in neutral beam injection-heated DT plasmas are presented, allowing thermal and non-thermal neutron component separation. Prospects for the diagnose of DT burning plasmas such as ITER and SPARC will be presented.

Published
2023
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6. Almost flat angles in surface superconductivity

Author

Michele Correggi and Emanuela L. Giacomelli

Subjects
Superconductivity, Surface (mathematics), Conjecture, Partial differential equation, Condensed Matter - Superconductivity, Applied Mathematics, Mathematical analysis, FOS: Physical sciences, General Physics and Astronomy, Order (ring theory), Statistical and Nonlinear Physics, Mathematical Physics (math-ph), Magnetic field, Superconductivity (cond-mat.supr-con), Mathematics - Analysis of PDEs, FOS: Mathematics, Ginzburg–Landau theory, Ground state, Mathematical Physics, Analysis of PDEs (math.AP), Mathematics
Abstract

Type-II superconductivity is known to persist close to the sample surface in presence of a strong magnetic field. As a consequence, the ground state energy in the Ginzburg-Landau theory is approximated by an effective one-dimensional model. As shown in [CG2], the presence of corners on the surface affects the energy of the sample with a non-trivial contribution. In [CG2], the two-dimensional model problem providing the corner energy is implicitly identified and, although no explicit dependence of the energy on the corner opening angle is derived, a conjecture about its form is proposed. We study here such a conjecture and confirm it, at least to leading order, for corners with almost flat opening angle., Comment: 22 pages, pdfLaTex

Published
2021
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7. A new hard x-ray spectrometer for runaway electron measurements in tokamaks

Author

A Dal Molin, M Nocente, M Dalla Rosa, E Panontin, D Rigamonti, M Tardocchi, A Shevelev, E Khilkevitch, M Iliasova, L Giacomelli, G Gorini, E Perelli Cippo, F D’Isa, G Pautasso, G Papp, G Tardini, E Macusova, J Cerovsky, O Ficker, M Salewski, V Kiptily, EUROfusion MST1 Team, COMPASS Team, and ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Applied Mathematics, Nuclear instruments and methods for hot plasma diagnostics, X-ray detectors, Instrumentation, Engineering (miscellaneous), Runaway electrons
Abstract

Runaway electron gamma-ray detection system, a novel hard x-ray (HXR) spectrometer optimized for bremsstrahlung radiation measurement from runaway electrons in fusion plasmas, has been developed. The detector is based on a 1‘×1’ LaBr3:Ce scintillator crystal coupled with a photomultiplier tube. The system has an energy dynamic range exceeding 20 MeV with an energy resolution of 3% at 661.7 keV. The detector gain is stable even under severe loads, with a gain shift that stays below 3% at HXR counting rates in excess of 1 MCps. The performance of the system enables unprecedented studies of the time-dependent runaway electron energy distribution function, as shown in recent runaway electron physics experiments at the ASDEX Upgrade and COMPASS tokamaks.

Published
2023
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8. Study of runaway electron dynamics at the ASDEX Upgrade tokamak during impurity injection using fast hard x-ray spectrometry

Author

A. Shevelev, E. Khilkevitch, M. Iliasova, M. Nocente, G. Pautasso, G. Papp, A.D. Molin, S.P. Pandya, V. Plyusnin, L. Giacomelli, G. Gorini, E. Panontin, D. Rigamonti, M. Tardocchi, G. Tardini, A. Patel, A. Bogdanov, I. Chugunov, D. Doinikov, V. Naidenov, I. Polunovsky, null the ASDEX Upgrade Team, null the EUROfusion MST1 Team, Shevelev, A, Khilkevitch, E, Iliasova, M, Nocente, M, Pautasso, G, Papp, G, Molin, A, Pandya, S, Plyusnin, V, Giacomelli, L, Gorini, G, Panontin, E, Rigamonti, D, Tardocchi, M, Tardini, G, Patel, A, Bogdanov, A, Chugunov, I, Doinikov, D, Naidenov, V, Polunovsky, I, ASDEX Upgrade Team, Max Planck Institute for Plasma Physics, Max Planck Society, and EUROfusion MST1 Team

Subjects
Nuclear and High Energy Physics, Tokamak, Materials science, gamma-ray spectrometry, Physics::Instrumentation and Detectors, diagnostics of hot plasma, Electron dynamics, Mass spectrometry, runaway electron, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, Nuclear physics, ASDEX Upgrade, Physics::Plasma Physics, Impurity, law, 0103 physical sciences, 010306 general physics, tokamak, X-ray, Condensed Matter Physics, 13. Climate action, Physics::Space Physics, hard X-ray, hard X-rays, runaway electrons
Abstract

To study the runaway electron (RE) dynamics during plasma discharge and develop scenarios for disruption mitigation, a hard X-ray (HXR) spectrometric system has been developed and commissioned at the ASDEX Upgrade tokamak (AUG). The diagnostic system consists of two high-performance spectrometers based on LaBr3(Ce) scintillation detectors supplied with advanced electronics and analysis algorithms. These spectrometers view the AUG tokamak chamber quasi-radially at the equatorial plane. The measurements were carried out in the RE beam generation regimes by injecting argon into a deuterium plasma. In the interaction of a developed RE beam with a heavy gas target, powerful bremsstrahlung flux is induced, reaching energy close to 20 MeV. The electron energy distributions were reconstructed from the measured HXR spectra by deconvolution methods. The experimentally obtained maximum RE energies at different discharge stages were compared with relativistic test particle simulations that include the effect of toroidal electric field, plasma collisional drag force, synchrotron deceleration force. It was observed that the electrons attain their maximum energies within 50-100 ms after the gas injection. It gradually decreases due to the drop in loop voltage, energy loss due to synchrotron radiation emission and collisions dissipation of energy with the background plasma. HXR measurements at the discharge with multiple deuterium pellet injections allowed observing the effects of plasma cooling and argon ion recombination after the pellet injections. Argon density in AUG plasma after massive gas injection was estimated using HXR measurements.

Published
2021
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9. Plasma heating and generation of energetic D ions with the 3-ion ICRF + NBI scenario in mixed H-D plasmas at JET-ILW

Author

J. Ongena, Y. Baranov, M. Nocente, M. F. F. Nave, L. Giacomelli, Jet Contributors, R. J. Dumont, Ye. O. Kazakov, Mirko Salewski, L. Meneses, J. Garcia, K. K. Kirov, S. E. Sharapov, Jacob Eriksson, Žiga Štancar, M. J. Mantsinen, V. G. Kiptily, F. Nabais, Teddy Craciunescu, Jari Varje, H. Weisen, M. Dreval, Kazakov, Y, Nocente, M, Mantsinen, M, Ongena, J, Baranov, Y, Craciunescu, T, Dreval, M, Dumont, R, Eriksson, J, Garcia, J, Giacomelli, L, Kiptily, V, Kirov, K, Meneses, L, Nabais, F, Nave, M, Salewski, M, Sharapov, S, Stancar, Z, Varje, J, Weisen, H, Department of Applied Physics, Aalto-yliopisto, and Aalto University

Subjects
icrf plus nbi synergies, Nuclear and High Energy Physics, Spectrum analyzer, Materials science, cyclotron range, Plasma heating, ICRF+NBI synergie, DIAGNOSTICS, ICRF+NBI synergies, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Ion, ICRF plus NBI synergies, PHYSICS, MODE CONVERSION, icrf, Physics::Plasma Physics, 3-ion icrf scenarios, 0103 physical sciences, diagnostics, Fast-ion generation, Neutron, 010306 general physics, Neutral particle, 3-ion ICRF scenario, mode conversion, Range (particle radiation), Jet (fluid), ICRF, mixed plasmas, Mixed plasmas, chapter 6, plasma heating, Plasma, Condensed Matter Physics, CHAPTER 6, CYCLOTRON RANGE, fast-ion generation, 3-ion ICRF scenarios, mixed plasma, Magnetohydrodynamics, Atomic physics, physics
Abstract

openaire: EC/H2020/633053/EU//EUROfusion Dedicated experiments were conducted in mixed H-D plasmas in JET to demonstrate the efficiency of the 3-ion ICRF scenario for plasma heating, relying on injected fast NBI ions as the resonant ion component. Strong core localization of the RF power deposition in the close vicinity of the ion-ion hybrid layer was achieved, resulting in an efficient plasma heating, generation of energetic D ions, strong enhancement of the neutron rate and observation of Alfvénic modes. A consistent physical picture that emerged from a range of fast-ion measurements at JET, including neutron and gamma-ray measurements, a high-energy neutral particle analyzer and MHD mode localization analysis, is presented. The possibility to moderate the fast-ion energies with the ratio P ICRF/P NBI and the choice of the NBI injectors is demonstrated. An outlook of possible applications of the 3-ion scenarios, including a recent example of its use in mixed D-3He plasmas in JET and promising scenarios for D-T plasmas, are presented.

Published
2020
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10. Role of JETPEAK database in validation of synthetic neutron camera diagnostics and ASCOT- AFSI fast particle and fusion product calculation chain in JET

Author

H. Weisen, L. Giacomelli, Jari Varje, and P. Siren

Subjects
Neutron emission, nuclear instruments and methods for hot plasma diagnostics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear instruments and methods for hot plasma diagnostics, computer.software_genre, 01 natural sciences, 030218 nuclear medicine & medical imaging, analysis and statistical methods, 03 medical and health sciences, 0302 clinical medicine, 0103 physical sciences, Neutron, Instrumentation, Mathematical Physics, Physics, Fusion, Jet (fluid), Database, 010308 nuclear & particles physics, simulation methods and programs, Distribution function, Product (mathematics), Orbit (dynamics), Analysis and statistical methods, Particle, Simulation methods and programs, computer
Abstract

JETPEAK is a comprehensive stationary-state database and a work environment for JET diagnostics data, processed data and simulations suitable for a wide variety of analytical tasks. It enables systematic modelling and efficient interpretation of synthetic neutron diagnostics and validation of fast particle and fusion product calculations. We present a processing chain connecting the ASCOT orbit following code and AFSI fusion source simulator Monte-Carlo codes, providing synthetic diagnostics data for systematic comparison with measured data and model validation. The ASCOT code defines the reactant distribution functions and the additional AFSI module creates fusion products as 4D (R, z, E, pitch) distributions, which serve as input for synthetic diagnostics calculations. In this contribution we present synthetic neutron emission rates for the JET neutron camera lines of sight. First results show a fair agreement of the synthetic camera results with the horizontal JET neutron cameras and systematic differences, which are not understood, between the ratios of neutron emission measurements and modelled for the vertical and horizontal cameras.

Published
2019
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11. First neutron spectroscopy measurements with a compact C7LYC based detector at EAST

Author

L. J. Ge, Ruhong Zhou, Yimo Zhang, Z. M. Hu, C. Cattadori, E. Perelli Cippo, G. Croci, M. Nocente, D. Rigamonti, Marica Rebai, Giuseppe Gorini, Marco Tardocchi, Tieshuan Fan, F. Camera, Andrea Muraro, G. Q. Zhong, L. Giacomelli, Liqun Hu, Rigamonti, D, Zhong, G, Croci, G, Giacomelli, L, Gorini, G, Hu, Z, Muraro, A, Nocente, M, Perelli Cippo, E, Rebai, M, Tardocchi, M, Camera, F, Cattadori, C, Zhou, R, Hu, L, Ge, L, Zhang, Y, and Fan, T

Subjects
fast neutrons), gas and liquid scintillators), Physics::Instrumentation and Detectors, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear instruments and methods for hot plasma diagnostics, Nuclear Theory, Nuclear instruments and methods for hot plasma diagnostic, 01 natural sciences, thermal, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Optics, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, Neutron, Nuclear Experiment, Instrumentation, Mathematical Physics, Physics, Spectrometer, 010308 nuclear & particles physics, business.industry, Detector, Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators), Neutral beam injection, Neutron spectroscopy, Neutron detectors (cold, scintillation and light emission processes (solid, Scintillators, Plasma diagnostics, business, Neutron detectors (cold, thermal, fast neutrons)
Abstract

The paper describes a new compact neutron spectrometer optimized for the detection of 2.5 MeV neutrons for fusion plasma applications. The first neutron spectroscopy measurements on a nuclear fusion plasma experiment (EAST) with this detector are also reported together with the data interpretation. The detector allowed separating the different neutron emission components from the plasma and to validate the effectiveness of the Neutral Beam Injection (NBI) heating. A possible improvement of the diagnostic has been also identified in order to increase the detector sensitivity to weak components of the neutron spectrum, such as those due to the Ion Cyclotron Resonace Heating (ICRH). The relatively simple response function of the (CLYC)-L-7 detector to 2.5 MeV neutrons together with its good capability in the n/gamma discrimination, makes this detector an interesting spectrometer for deuterium (D) plasma diagnostics. In particular, its compactness allows for integration in a multi-line of sight camera where space constraints are present.

Published
2019
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12. 14 MeV calibration of JET neutron detectors—phase 2: in-vessel calibration

Author

A. Peacock, R. Price, A. Reed, Jet Contributors, Paola Batistoni, Peter Hawkins, Sean Conroy, V. Krasilnikov, J. Stephens, K. Keogh, Mario Pillon, Stefano Loreti, Jakub Bielecki, D. Rigamonti, Z. Ghani, E. Laszynska, Sergey Popovichev, A. Cufar, L. Giacomelli, J. Dankowski, Slawomir Jednorog, Pillon, M., Loreti, S., and Batistoni, P.

Subjects
Physics, Nuclear and High Energy Physics, Neutron transport, Neutron emission, fusion power measurement, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, neutron calibration, Fusion power, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, Neutron temperature, 010305 fluids & plasmas, Nuclear physics, Neutron generator, 0103 physical sciences, fusion reactor, Neutron detection, Neutron source, Neutron, Nuclear Experiment, 010306 general physics
Abstract

A new DT campaign (DTE2) is planned at JET in 2020 to minimize the risks of ITER operations. In view of DT operations, a calibration of the JET neutron monitors at 14 MeV neutron energy has been performed using a well calibrated 14 MeV neutron generator (NG) deployed, together with its power supply and control unit, inside the vacuum vessel by the JET remote handling system. The NG was equipped with two calibrated diamond detectors, which continuously monitored its neutron emission rate during the calibration, and activation foils which provided the time integrated yield. Cables embedded in the remote handling boom were used to power the neutron generator, the active detectors and pre-amplifier, and to transport the detectors' signal. The monitoring activation foils were retrieved at the end of each day for decay γ-ray counting, and replaced by fresh ones. About 76 hours of irradiation, in 9 days, were needed with the neutron generator in 73 different poloidal and toroidal positions in order to calibrate the two neutron yield measuring systems available at JET, the 235U fission chambers (KN1) and the inner activation system (KN2). The NG neutron emission rates provided by the monitoring detectors were in agreement within 3%. Neutronics calculations have been performed using MCNP code and a detailed model of JET to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the NG neutrons, and taking into account the anisotropy of the neutron generator and all the calibration circumstances. These calculations have made use of a very detailed and validated geometrical description of the neutron generator and of the modified MNCP neutron source subroutine producing neutron energy-angle distribution for the neutrons emitted by the NG. The KN1 calibration factor for a DT plasma has been determined with ±4.2% experimental uncertainty. Corrections due to NG and remote handling effects and the plasma volume effect have been calculated by simulation modelling. The related additional uncertainties are difficult to estimate, however the results of the previous calibration in 2013 have demonstrated that such uncertainties due to modelling are globally ±3%. It has been found that the difference between KN1 response to DD neutrons and that to DT neutrons is within the uncertainties in the derived responses. KN2 has been calibrated using the 93Nb(n,2n)92mNb and 27Al(n,a)24Na activation reactions (energy thresholds 10 MeV and 5 MeV, respectively). The total uncertainty on the calibration factors is ±6% for 93Nb(n,2n)92mNb and ±8% 27Al(n,a)24Na (1σ). The calibration factors of the two independent systems KN1 and KN2 will be validated during DT operations. The experience gained and the lessons learnt are presented and discussed in particular with regard to the 14 MeV neutron calibrations in ITER. © 2018 EURATOM.

Published
2018
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13. Conceptual design of the radial gamma ray spectrometers system forαparticle and runaway electron measurements at ITER

Author

J. Rzadkiewicz, E. Perelli Cippo, Gabriele Croci, Ana C. Fernandes, Mirko Salewski, Igor Lengar, Marica Rebai, Robin Barnsley, M. Tardocchi, L. Giacomelli, João M. C. Sousa, R. C. Pereira, V. Krasilnikov, D. Rigamonti, P. Santosh, Giuseppe Gorini, I. Zychor, Marek Moszynski, L. Di Pace, A. Muraro, Massimo Nocente, B. Brichard, G. Brolatti, Luciano Bertalot, Di Pace, L., Brolatti, G., Nocente, M, Tardocchi, M, Barnsley, R, Bertalot, L, Brichard, B, Croci, G, Brolatti, G, Di Pace, L, Fernandes, A, Giacomelli, L, Lengar, I, Moszynski, M, Krasilnikov, V, Muraro, A, Pereira, R, Perelli Cippo, E, Rigamonti, D, Rebai, M, Rzadkiewicz, J, Salewski, M, Santosh, P, Sousa, J, Zychor, I, and Gorini, G

Subjects
Nuclear and High Energy Physics, Tokamak, Astrophysics::High Energy Astrophysical Phenomena, Electron, runaway electron, 01 natural sciences, Runaway electrons, 010305 fluids & plasmas, law.invention, Nuclear physics, law, ITER, 0103 physical sciences, Nuclear fusion, Neutron, Gamma-ray spectroscopy, 010306 general physics, nuclear fusion, Alpha particles, Physics, Range (particle radiation), alpha particles, runaway electrons, Gamma ray spectroscopy, Bremsstrahlung, Gamma ray, Condensed Matter Physics, Distribution function, Alpha particle
Abstract

We here present the principles and main physics capabilities behind the design of the radial gamma ray spectrometers (RGRS) system for alpha particle and runaway electron measurements at ITER. The diagnostic benefits from recent advances in gamma-ray spectrometry for tokamak plasmas and combines space and high energy resolution in a single device. The RGRS system as designed can provide information on α particles on a time scale of 1/10 of the slowing down time for the ITER 500 MW full power DT scenario. Spectral observations of the 3.21 and 4.44 MeV peaks from the 9Be(α, nγ)12C reaction make the measurements sensitive to α particles at characteristic resonant energies and to possible anisotropies of their slowing down distribution function. An independent assessment of the neutron rate by gamma-ray emission is also feasible. In case of runaway electrons born in disruptions with a typical duration of 100 ms, a time resolution of at least 10 ms for runaway electron studies can be achieved depending on the scenario and down to a current of 40 kA by use of external gas injection. We find that the bremsstrahlung spectrum in the MeV range from confined runaways is sensitive to the electron velocity space up to E≈30-40 MeV, which allows for measurements of the energy distribution of the runaway electrons at ITER. © 2017 IOP Publishing Ltd.

Published
2017
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14. Fission diamond detectors for fast-neutron ToF spectroscopy

Author

E. Milani, G. Verona Rinati, Carla Andreani, L. Giacomelli, Claudio Verona, M. Tardocchi, Christopher D. Frost, E. Perelli Cippo, Marica Rebai, Erik Schooneveld, Marco Marinelli, Antonino Pietropaolo, Giuseppe Gorini, Alberto Fazzi, Pietropaolo, A, Andreani, C, Rebai, M, Giacomelli, L, Gorini, G, Perelli Cippo, E, Tardocchi, M, Fazzi, A, Verona Rinati, G, Verona, C, Marinelli, M, Milani, E, Frost, C, and Schooneveld, E

Subjects
Materials science, EFFICIENCY TIME, business.industry, Fission, General Physics and Astronomy, Diamond, tof spectroscopy, engineering.material, Settore FIS/03 - Fisica della Materia, CHEMICAL-VAPOR-DEPOSITION, Optics, FIS/01 - FISICA SPERIMENTALE, Beamline, engineering, Neutron source, Physics::Accelerator Physics, Neutron, Spallation, business, Spectroscopy, Nuclear Experiment, diamond detector, Beam (structure)
Abstract

A novel type of fast-neutron (energy En>1 MeV) counter is presented. It is made of a fissionable natural-uranium foil faced to an intrinsic single-crystal diamond that detects the neutron-induced fission fragments escaping the uranium sheet. The fast response of the diamond is a key feature for its use at pulsed spallation neutron sources for applications in beam monitoring and spectrum measurements with mm spatial resolution. This is an important issue to be addressed in the development of beam lines dedicated to the investigation of the so-called single-event effects in electronics, such as the ChipIr instrument designed for the ISIS spallation source in the UK. Tests of the device at the ROTAX beam line at ISIS have shown its potentiality for the proposed application. © Europhysics Letters Association, 2011.

Published
2011
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15. Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET

Author

Sean Conroy, Jet Contributors, Thomas Johnson, M. Nocente, F. Binda, Tuomas Koskela, M. Skiba, Matthias Weiszflog, S. E. Sharapov, L. Giacomelli, M. Schneider, Giuseppe Gorini, Carl Hellesen, Jacob Eriksson, Carlo Cazzaniga, A. S. Jacobsen, Mirko Salewski, Anders Hjalmarsson, V. G. Kiptily, Torbjörn Hellsten, M. Tardocchi, Göran Ericsson, M. Mantsinen, Barcelona Supercomputing Center, Eriksson, J, Nocente, M, Binda, F, Cazzaniga, C, Conroy, S, Ericsson, G, Giacomelli, L, Gorini, G, Hellesen, C, Hellsten, T, Hjalmarsson, A, Jacobsen, A, Johnson, T, Kiptily, V, Koskela, T, Mantsinen, M, Salewski, M, Schneider, M, Sharapov, S, Skiba, M, Tardocchi, M, Weiszflog, M, and Croci, G

Subjects
Nuclear and High Energy Physics, Plasma and Space Physics, Tokamak, Fluids & Plasmas, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Condensed Matter Physic, Atomic, law.invention, Nuclear physics, Particle and Plasma Physics, MeV range, Physics::Plasma Physics, law, Gamma rays--Measurement, Nuclear, Neutron, Gamma spectroscopy, fast ions, Gamma-ray spectroscopy, Radio frequency identification systems, Fusion, Nuclear Experiment, Physics, Range (particle radiation), Jet (fluid), Enginyeria biomèdica [Àrees temàtiques de la UPC], Espectrometria de raigs gamma, Molecular, Fast ions, Condensed Matter Physics, neutron spectroscopy, Gamma ray spectrometer, gamma-ray spectroscopy, Deuterium, Physics::Accelerator Physics, Neutron spectrometry, Atomic physics, Third harmonic, Beam (structure)
Abstract

Observations made in a JET experiment aimed at accelerating deuterons to the MeV range by third harmonic radio-frequency (RF) heating coupled into a deuterium beam are reported. Measurements are based on a set of advanced neutron and gamma-ray spectrometers that, for the first time, observe the plasma simultaneously along vertical and oblique lines of sight. Parameters of the fast ion energy distribution, such as the high energy cut-off of the deuteron distribution function and the RF coupling constant, are determined from data within a uniform analysis framework for neutron and gamma-ray spectroscopy based on a one-dimensional model and by a consistency check among the individual measurement techniques. A systematic difference is seen between the two lines of sight and is interpreted to originate from the sensitivity of the oblique detectors to the pitch-angle structure of the distribution around the resonance, which is not correctly portrayed within the adopted one dimensional model. A framework to calculate neutron and gamma-ray emission from a spatially resolved, two-dimensional deuteron distribution specified by energy/pitch is thus developed and used for a first comparison with predictions from ab initio models of RF heating at multiple harmonics. The results presented in this paper are of relevance for the development of advanced diagnostic techniques for MeV range ions in high performance fusion plasmas, with applications to the experimental validation of RF heating codes and, more generally, to studies of the energy distribution of ions in the MeV range in high performance deuterium and deuterium-tritium plasmas. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Published
2015
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16. Corrigendum: Runaway electron beam generation and mitigation during disruptions at JET-ILW (2015 Nucl. Fusion 55 093013)

Author

A. Boboc, Michael Lehnen, I. H. Coffey, Diogo Alves, V. Riccardo, A. Fil, J. Decker, G. F. Matthews, Stéphane Devaux, G. Sips, Eric Nardon, J. Mlynář, S. Brezinsek, R. Koslowski, C. Perez von Thun, E. Nilsson, A. E. Shevelev, C. Reux, S.N. Gerasimov, A. Martin de Aguilera, U. Kruezi, Ivan Lupelli, B. Alper, S. Jachmich, Jet Contributors, P. Drewelow, A. Manzanares, V. Plyusnin, B. Bazylev, E.M. Khilkevitch, Eva Belonohy, P. de Vries, V. G. Kiptily, F. Saint-Laurent, L. Giacomelli, P. J. Lomas, Carlo Sozzi, and JET Contributors

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Fusion, Jet (fluid), Cathode ray, Condensed Matter Physics
Published
2015
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17. Response of a single-crystal diamond detector to fast neutrons

Author

E. Perelli Cippo, Alberto Fazzi, M. Tardocchi, Giuseppe Gorini, Alberto Milocco, Antonino Pietropaolo, L. Giacomelli, Marica Rebai, Rebai, M, Milocco, A, Giacomelli, L, Cippo, E, Tardocchi, M, Fazzi, A, Pietropaolo, A, and Gorini, G

Subjects
fast neutrons), Bonner sphere, Physics, Instrumentation for neutron sources, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Neutron scattering, Neutron radiation, Neutron time-of-flight scattering, Neutron temperature, Diamond Detectors, thermal, Neutron detectors (cold, Nuclear physics, Instrumentation for neutron sources, Diamond Detectors, Neutron detectors (cold, Neutron cross section, Neutron source, Neutron detection, Instrumentation for neutron source, Nuclear Experiment, Instrumentation, Diamond Detector, Neutron detectors (cold, thermal, fast neutrons), Mathematical Physics
Abstract

Bi-parametric (neutron time of flight and deposited energy) measurements using a Single-crystal Diamond Detector (4.5 × 4.5 × 0.5 mm 3 active volume) were performed at the nTOF neutron facility at CERN. The time structure of the neutron beam combined with the long flight path allowed for measurements of the diamond detector response to quasi monoenergetic neutrons in the energy range up to 40 MeV. Deposited energy spectra were compared to MCNPX simulations using different cross section libraries. The results can be used for the interpretation of Single-crystal Diamond Detector measurements of fast neutrons at spallation neutron sources.© 2013 IOP Publishing Ltd and Sissa Medialab srl.

Published
2013
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18. Single-crystal diamond detector for time-resolved measurements of a pulsed fast-neutron beam

Author

Claudio Verona, Marica Rebai, Giuseppe Gorini, Christopher D. Frost, Marco Marinelli, E. Perelli Cippo, E. Milani, M. Tardocchi, Carla Andreani, Antonino Pietropaolo, L. Giacomelli, Erik Schooneveld, G. Verona Rinati, Alberto Fazzi, Pietropaolo, A, Andreani, C, Rebai, M, Giacomelli, L, Gorini, G, Perelli Cippo, E, Tardocchi, M, Fazzi, A, Verona Rinati, G, Verona, C, Marinelli, M, Milani, E, Frost, C, and Schooneveld, E

Subjects
Materials science, Astrophysics::High Energy Astrophysical Phenomena, Schottky barrier, General Physics and Astronomy, engineering.material, nuclear spallation, neutron, Optics, Neutron detection, Spallation, Nuclear Experiment, business.industry, Settore FIS/01 - Fisica Sperimentale, Detector, Diamond, Neutron radiation, Schottky barriers, time of flight spectrometers, neutron effects, FIS/01 - FISICA SPERIMENTALE, time resolved spectroscopy, chemical vapour deposition, engineering, neutron sources, Neutron source, diamond detector, business, Spallation Neutron Source
Abstract

A fast-neutron detector for time-resolved beam measurements at spallation neutron sources is presented. The device features a p-type/intrinsic/metal Schottky barrier structure where the active (intrinsic) detection layer is a 150 μm thick single-crystal diamond obtained by chemical-vapour deposition. Coupling to fast front-end electronics preserves the excellent timing properties of the device as demonstrated in tests performed at the ISIS spallation neutron source in UK. The device represents a novel approach in the field of pulsed fast-neutrons spectroscopic techniques. It will find immediate application in localized (mm resolution) fast-neutron fluence measurements required by neutron irradiation experiments at ISIS also envisaging its use for spectrum measurements.

Published
2010
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19. Fundamental ion cyclotron resonance heating of JET deuterium plasmas

Author

Anders Hjalmarsson, G. Bonheure, V. G. Kiptily, V. Vdovin, A. Walden, J. Mailloux, A. V. Krasilnikov, M. Santala, J. Ongena, T. M. Biewer, D. Van Eester, L. Giacomelli, Marco Riva, Yu. A. Kaschuck, H. Leggate, Sergey Popovichev, Kristel Crombé, Carl Hellesen, Jan Källne, M.-L. Mayoral, S. Jachmich, B. Esposito, Göran Ericsson, Jet-Efda Contributors, Jet Efda Task Force Heating, V. N. Amosov, Daniele Marocco, M.F. Stamp, and E. Lerche

Subjects
education.field_of_study, Materials science, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Population, Cyclotron, Fusion power, Condensed Matter Physics, Neutral beam injection, law.invention, Nuclear Energy and Engineering, Physics::Plasma Physics, law, Dielectric heating, Nuclear fusion, Neutron, Atomic physics, education
Abstract

Radio frequency heating of majority ions is of prime importance for understanding the basic role of auxiliary heating in the activated D-T phase of ITER. Majority deuterium ion cyclotron resonance heating (ICRH) experiments at the fundamental cyclotron frequency were performed in JET. In spite of the poor antenna coupling at 25 MHz, this heating scheme proved promising when adopted in combination with D neutral beam injection (NBI). The effect of fundamental ICRH of a D population was clearly demonstrated in these experiments: by adding similar to 25% of heating power the fusion power was increased up to 30-50%, depending on the type of NBI adopted. At this power level, the ion and electron temperatures increased from T-i similar to 4.0 keV and T-e similar to 4.5 keV (NBI-only phase) to T-i similar to 5.5 keV and T-e similar to 5.2 keV (ICRH + NBI phase), respectively. The increase in the neutron yield was stronger when 80 keV rather than 130 keV deuterons were injected in the plasma. It is shown that the neutron rate, the diamagnetic energy and the electron as well as the ion temperature scale roughly linearly with the applied RF power. A synergistic effect of the combined use of ICRF and NBI heating was observed: (i) the number of neutron counts measured by the neutron camera during the combined ICRF + NBI phases of the discharges exceeded the sum of the individual counts of the NBI-only and ICRF-only phases; (ii) a substantial increase in the number of slowing-down beam ions was detected by the time of flight neutron spectrometer when ICRF power was switched on; (iii) a small D subpopulation with energies slightly above the NBI launch energy was detected by the neutral particle analyzer and gamma-ray spectroscopy.

Published
2009
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20. Triton burn-up neutron emission in JET low current plasmas

Author

Sergey Popovichev, Göran Ericsson, Efda Jet contributors, Sean Conroy, Henrik Sjöstrand, Giuseppe Gorini, D. Palma, Jan Källne, M. Weiszflog, A. Hjalmarsson, L. Giacomelli, H. Henriksson, M. Tardocchi, Sjostrand, H, Gorini, G, Conroy, S, Ericsson, G, Giacomelli, L, Henriksson, H, Hjalmarsson, A, Kallne, J, Palma, D, Popovichev, S, Tardocchi, M, Weiszflog, M, and EFDA JET, C

Subjects
Jet (fluid), Materials science, Acoustics and Ultrasonics, Proton, Chemistry, Neutron emission, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, Neutron stimulated emission computed tomography, Analytical chemistry, Plasma, Condensed Matter Physics, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Nuclear physics, Neutron measurements, nuclear fusion, Deuterium, Physics::Plasma Physics, Physics::Accelerator Physics, Nuclear fusion, Tritium, Neutron, Current (fluid), Nuclear Experiment, Spectroscopy
Abstract

The 14 MeV neutron emission from JET deuterium discharges is analysed on the basis of the information on all neutron diagnostics available on JET. This emission is due to the d + t → α + n reaction, mainly, the triton burn-up process, and is used to determine the fast triton confinement. A simplified model for triton burn-up neutron emission has been used and provides an adequate description of the 14 MeV emission. First orbit triton losses are found to amount to 50%, 20% and 10% at Ip = 1 MA, 2 MA and 3 MA, respectively. Neutron emission spectroscopy measurements with the magnetic proton recoil neutron spectrometer have detected a contribution to the 14 MeV emission due to residual tritium. For the selected (low impurity) discharges analysed in this paper 15% of the 14 MeV emission comes from the residual tritium reactions. It is also found that the residual tritium concentration tends to increase with increasing impurity content.

Published
2008
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21. Runaway electron beam dynamics at low plasma density in DIII-D: energy distribution, current profile, and internal instability.

Author

A. Lvovskiy, C. Paz-Soldan, N.W. Eidietis, P. Aleynikov, M.E. Austin, A. Dal Molin, Y.Q. Liu, R.A. Moyer, M. Nocente, D. Shiraki, L. Giacomelli, W.W. Heidbrink, E.M. Hollmann, D. Rigamonti, D.A. Spong, and M. Tardocchi

Subjects
BEAM dynamics, PLASMA density, PLASMA dynamics, ELECTRON beams, ENERGY density, HARD X-rays
Abstract

Parameters of the post-disruption runaway electron (RE) beam in the low density background plasma achieved after secondary deuterium injection are investigated in DIII-D. The spatially resolved RE energy distribution function is measured for the first time during the RE plateau stage by inverting hard x-ray bremsstrahlung spectra. It has maximum energy up to 20 MeV and a non-monotonic feature at 5–6 MeV observed only in the core of the beam supporting the possibility of kinetic instabilities. Results of Fokker-Plank modelling qualitatively support the formation of the non-monotonic distribution function. The RE current profile is reconstructed for the first time using the spatially resolved RE energy distribution. It is found to be more peaked than the pre-disruption plasma current, with higher internal inductance, suggesting preferential formation of REs in the core plasma or potentially a radially inward motion of REs. The accessed relatively low current (180 kA) RE beam is found to be MHD stable, likely due to its elevated safety factor profile. From this base stable equilibrium, an internal beam instability is accessed by ramping up the current. The instability leads to a sawtooth-like relaxation of the RE current profile, but drives no RE loss. An internal kink mode proposed as a candidate instability is supported by results of MARS-F modelling. Electron cyclotron emission (ECE) spectrum measured during the low density RE plateau is found to be bifurcated, with a break point at ≈ 100 GHz, suggesting resonant absorption of the ECE at low frequencies. [ABSTRACT FROM AUTHOR]

Published
2020
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22. MeV range particle physics studies in tokamak plasmas using gamma-ray spectroscopy.

Author

M Nocente, A Dal Molin, N Eidietis, L Giacomelli, G Gorini, Y Kazakov, E Khilkevitch, V Kiptily, M Iliasova, A Lvovskiy, M Mantsinen, A Mariani, E Panontin, G Papp, G Pautasso, C Paz-Soldan, D Rigamonti, M Salewski, A Shevelev, and M Tardocchi

Subjects
PARTICLE physics, NUCLEAR fusion, TRITIUM, SPECTROMETRY, DISTRIBUTION (Probability theory), FAST ions
Abstract

Gamma-ray spectroscopy (GRS) has become an established technique to determine properties of the distribution function of the energetic particles in the MeV range, which are fast ions from heating and fusion reactions or runaway electrons born in disruptions. In this paper we present a selection of recent results where GRS is key to investigate the physics of MeV range particles. These range from radio-frequency heating experiments, where theoretical models can be tested with an unprecedented degree of accuracy, to disruption mitigation studies, where GRS sheds light on the effect of the actuators on the runaway electron velocity space. We further discuss the unique observational capabilities offered by the technique in deuterium–tritium plasmas, particularly with regard to the inference of the energy- and pitch-resolved distribution function of the α particles born from fusion reactions in the plasma core. [ABSTRACT FROM AUTHOR]

Published
2020
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23. Measuring fast ions in fusion plasmas with neutron diagnostics at JET.

Author

J Eriksson, C Hellesen, F Binda, M Cecconello, S Conroy, G Ericsson, A Hjalmarsson, A Sahlberg, L Giacomelli, M Tardocchi, G Gorini, M Nocente, V G Kiptily, S Sharapov, M Mantsinen, M Salewski, and Contributors, JET

Subjects
NUCLEAR fusion, PLASMA physics, NEUTRONS, TOKAMAKS, GAMMA rays
Abstract

Fast ions in fusion plasmas often leave characteristic signatures in the neutron emission from the plasma. In this paper, we show how neutron measurements can be used to study fast ions and give examples of physics results obtained on present day tokamaks. The focus is on measurements with dedicated neutron spectrometers and with compact neutron detectors used in each channel of neutron profile monitors. A measured neutron spectrum can be analyzed in several different ways, depending on the physics scenario under consideration. Gross features of a fast ion energy distribution can be studied by applying suitably chosen thresholds to the measured spectrum, thus probing ions with different energies. With this technique it is possible to study the interaction between fast ions and MHD activity, such as toroidal Alfvén eigenmodes (TAEs) and sawtooth instabilities. Quantitative comparisons with modeling can be performed by a direct computation of the neutron emission expected from a given fast ion distribution. Within this framework it is also possible to determine physics parameters, such as the supra-thermal fraction of the neutron emission, by fitting model parameters to the data. A detailed, model-independent estimate of the fast ion distribution can be obtained by analyzing the data in terms of velocity space weight functions. Using this method, fast ion distributions can be resolved in both energy and pitch by combining neutron and gamma-ray measurements obtained along several different sightlines. Fast ion measurements of the type described in this paper will also be possible at ITER, provided that the spectrometers have the dynamic range required to resolve the fast ion spectral features in the presence of the dominating thermonuclear neutron emission. A dedicated high-resolution neutron spectrometer has been designed for this purpose. [ABSTRACT FROM AUTHOR]

Published
2019
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24. The role of kinetic instabilities in formation of the runaway electron current after argon injection in DIII-D.

Author

A Lvovskiy, C Paz-Soldan, N W Eidietis, A Dal Molin, X D Du, L Giacomelli, J L Herfindal, E M Hollmann, L Martinelli, R A Moyer, M Nocente, D Rigamonti, D Shiraki, M Tardocchi, and K E Thome

Subjects
ARGON, DISTRIBUTION (Probability theory), PLASMA waves, CYCLOTRON resonance, ELECTRON temperature, KINETIC energy
Abstract

Kinetic instabilities in the MHz range driven by runaway electrons (REs) have been observed for the first time during the current quench (CQ) in disruptions triggered by massive injection of argon in DIII-D. These instabilities are well-correlated with intermittent RE losses in the beginning of RE current formation. The runaway current phase is not observed when the power of instabilities exceeds a threshold. Novel measurements of the RE distribution function during the CQ indicate that the instabilities appear when RE energy (ERE) exceeds 2.5–3 MeV, the number of modes grows linearly with ERE, and their frequencies lie in the range 0.1–3 MHz, below the ion cyclotron frequency. Possible plasma waves exciting by REs in this region are proposed. Increase of the amount of injected argon decreases the ERE and increases the success rate of the runaway current formation, while increase of the pre-disruption plasma current acts in the opposite direction. No dependence on the pre-disruption core electron temperature is found. [ABSTRACT FROM AUTHOR]

Published
2018
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25. 14 MeV calibration of JET neutron detectors—phase 2: in-vessel calibration.

Author

P. Batistoni, S. Popovichev, Z. Ghani, A. Cufar, L. Giacomelli, P. Hawkins, K. Keogh, S. Jednorog, E. Laszynska, S. Loreti, A. Peacock, M. Pillon, R. Price, A. Reed, D. Rigamonti, J. Stephens, J. Bielecki, S. Conroy, J. Dankowski, and V. Krasilnikov

Subjects
NEUTRON counters, NEUTRON generators, NEUTRON emission, COMPUTER simulation
Abstract

A new DT campaign (DTE2) is planned at JET in 2020 to minimize the risks of ITER operations. In view of DT operations, a calibration of the JET neutron monitors at 14 MeV neutron energy has been performed using a well calibrated 14 MeV neutron generator (NG) deployed, together with its power supply and control unit, inside the vacuum vessel by the JET remote handling system. The NG was equipped with two calibrated diamond detectors, which continuously monitored its neutron emission rate during the calibration, and activation foils which provided the time integrated yield. Cables embedded in the remote handling boom were used to power the neutron generator, the active detectors and pre-amplifier, and to transport the detectors’ signal. The monitoring activation foils were retrieved at the end of each day for decay γ-ray counting, and replaced by fresh ones. About 76 hours of irradiation, in 9 days, were needed with the neutron generator in 73 different poloidal and toroidal positions in order to calibrate the two neutron yield measuring systems available at JET, the 235U fission chambers (KN1) and the inner activation system (KN2). The NG neutron emission rates provided by the monitoring detectors were in agreement within 3%. Neutronics calculations have been performed using MCNP code and a detailed model of JET to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the NG neutrons, and taking into account the anisotropy of the neutron generator and all the calibration circumstances. These calculations have made use of a very detailed and validated geometrical description of the neutron generator and of the modified MNCP neutron source subroutine producing neutron energy-angle distribution for the neutrons emitted by the NG. The KN1 calibration factor for a DT plasma has been determined with  ±4.2% experimental uncertainty. Corrections due to NG and remote handling effects and the plasma volume effect have been calculated by simulation modelling. The related additional uncertainties are difficult to estimate, however the results of the previous calibration in 2013 have demonstrated that such uncertainties due to modelling are globally  ⩽  ±3%. It has been found that the difference between KN1 response to DD neutrons and that to DT neutrons is within the uncertainties in the derived responses. KN2 has been calibrated using the 93Nb(n,2n)92mNb and 27Al(n,a)24Na activation reactions (energy thresholds 10 MeV and 5 MeV, respectively). The total uncertainty on the calibration factors is  ±6% for 93Nb(n,2n)92mNb and  ±8% 27Al(n,a)24Na (1σ). The calibration factors of the two independent systems KN1 and KN2 will be validated during DT operations. The experience gained and the lessons learnt are presented and discussed in particular with regard to the 14 MeV neutron calibrations in ITER. [ABSTRACT FROM AUTHOR]

Published
2018
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26. Scenario development for the observation of alpha-driven instabilities in JET DT plasmas.

Author

R. J. Dumont, J. Mailloux, V. Aslanyan, M. Baruzzo, C.D. Challis, I. Coffey, A. Czarnecka, E. Delabie, J. Eriksson, J. Faustin, J. Ferreira, M. Fitzgerald, J. Garcia, L. Giacomelli, C. Giroud, N. Hawkes, Ph. Jacquet, E. Joffrin, T. Johnson, and D. Keeling

Subjects
PLASMA gases, TOKAMAKS, NUCLEAR fusion, PLASMA physics, PROTONS
Abstract

In DT plasmas, toroidal Alfvén eigenmodes (TAEs) can be made unstable by the alpha particles resulting from fusion reactions, and may induce a significant redistribution of fast ions. Recent experiments have been conducted in JET deuterium plasmas in order to prepare scenarios aimed at observing alpha-driven TAEs in a future JET DT campaign. Discharges at low density, large core temperatures associated with the presence of internal transport barriers and characterised by good energetic ion confinement have been performed. ICRH has been used in the hydrogen minority heating regime to probe the TAE stability. The consequent presence of MeV ions has resulted in the observation of TAEs in many instances. The impact of several key parameters on TAE stability could therefore be studied experimentally. Modeling taking into account NBI and ICRH fast ions shows good agreement with the measured neutron rates, and has allowed predictions for DT plasmas to be performed. [ABSTRACT FROM AUTHOR]

Published
2018
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27. Neutron spectroscopy measurements of 14 MeV neutrons at unprecedented energy resolution and implications for deuterium–tritium fusion plasma diagnostics.

Author

D Rigamonti, L Giacomelli, G Gorini, M Nocente, M Rebai, M Tardocchi, M Angelone, P Batistoni, A Cufar, Z Ghani, S Jednorog, A Klix, E Laszynska, S Loreti, M Pillon, S Popovichev, N Roberts, D Thomas, and Contributors, JET

Subjects
NEUTRON spectroscopy, DEUTERIUM compounds, PLASMA diagnostics
Abstract

An accurate calibration of the JET neutron diagnostics with a 14 MeV neutron generator was performed in the first half of 2017 in order to provide a reliable measurement of the fusion power during the next JET deuterium–tritium (DT) campaign. In order to meet the target accuracy, the chosen neutron generator has been fully characterized at the Neutron Metrology Laboratory of the National Physical Laboratory (NPL), Teddington, United Kingdom. The present paper describes the measurements of the neutron energy spectra obtained using a high-resolution single-crystal diamond detector (SCD). The measurements, together with a new neutron source routine ‘ad hoc’ developed for the MCNP code, allowed the complex features of the neutron energy spectra resulting from the mixed D/T beam ions interacting with the T/D target nuclei to be resolved for the first time. From the spectral analysis a quantitative estimation of the beam ion composition has been made. The unprecedented intrinsic energy resolution (<1% full width at half maximum (FWHM) at 14 MeV) of diamond detectors opens up new prospects for diagnosing DT plasmas, such as, for instance, the possibility to study non-classical slowing down of the beam ions by neutron spectroscopy on ITER. [ABSTRACT FROM AUTHOR]

Published
2018
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28. 14 MeV calibration of JET neutron detectors—phase 1: calibration and characterization of the neutron source.

Author

P. Batistoni, S. Popovichev, A. Cufar, Z. Ghani, L. Giacomelli, S. Jednorog, A. Klix, S. Lilley, E. Laszynska, S. Loreti, L. Packer, A. Peacock, M. Pillon, R. Price, M. Rebai, D. Rigamonti, N. Roberts, M. Tardocchi, D. Thomas, and Contributors, Jet

Subjects
CALIBRATION, SPECTROMETERS, NEUTRON counters, FUSION reactors, COMPUTED tomography
Abstract

In view of the planned DT operations at JET, a calibration of the JET neutron monitors at 14 MeV neutron energy is needed using a 14 MeV neutron generator deployed inside the vacuum vessel by the JET remote handling system. The target accuracy of this calibration is  ±10% as also required by ITER, where a precise neutron yield measurement is important, e.g. for tritium accountancy. To achieve this accuracy, the 14 MeV neutron generator selected as the calibration source has been fully characterised and calibrated prior to the in-vessel calibration of the JET monitors. This paper describes the measurements performed using different types of neutron detectors, spectrometers, calibrated long counters and activation foils which allowed us to obtain the neutron emission rate and the anisotropy of the neutron generator, i.e. the neutron flux and energy spectrum dependence on emission angle, and to derive the absolute emission rate in 4π sr. The use of high resolution diamond spectrometers made it possible to resolve the complex features of the neutron energy spectra resulting from the mixed D/T beam ions reacting with the D/T nuclei present in the neutron generator target. As the neutron generator is not a stable neutron source, several monitoring detectors were attached to it by means of an ad hoc mechanical structure to continuously monitor the neutron emission rate during the in-vessel calibration. These monitoring detectors, two diamond diodes and activation foils, have been calibrated in terms of neutrons/counts within  ±5% total uncertainty. A neutron source routine has been developed, able to produce the neutron spectra resulting from all possible reactions occurring with the D/T ions in the beam impinging on the Ti D/T target. The neutron energy spectra calculated by combining the source routine with a MCNP model of the neutron generator have been validated by the measurements. These numerical tools will be key in analysing the results from the in-vessel calibration and to derive the response of the JET neutron detectors to DT plasma neutrons starting from the response to the generator neutrons, and taking into account all the calibration circumstances. [ABSTRACT FROM AUTHOR]

Published
2018
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29. Runaway electron mitigation by 3D fields in the ASDEX-Upgrade experiment.

Author

M Gobbin, L Li, Y Q Liu, L Marrelli, M Nocente, G Papp, G Pautasso, P Piovesan, M Valisa, D Carnevale, B Esposito, L Giacomelli, M Gospodarczyk, P J McCarthy, P Martin, W Suttrop, M Tardocchi, M Teschke, Team, the ASDEX Upgrade, and Team, the EUROfusion MST1

Subjects
ELECTRON beams, TOKAMAKS, PERTURBATION theory, X-ray spectra, APPROXIMATION theory, ELECTRIC discharges
Abstract

Disruption-generated runaway electron (RE) beams represent a severe threat for tokamak plasma-facing components in high current devices like ITER, thus motivating the search of mitigation techniques. The application of 3D fields might aid this purpose and recently was investigated also in the ASDEX Upgrade experiment by using the internal active saddle coils (termed B-coils). Resonant magnetic perturbations (RMPs) with dominant toroidal mode number n = 1 have been applied by the B-coils, in a RE specific scenario, before and during disruptions, which are deliberately created via massive gas injection. The application of RMPs affects the electron temperature profile and seemingly changes the dynamics of the disruption; this results in a significantly reduced current and lifetime of the generated RE beam. A similar effect is observed also in the hard-x-ray (HXR) spectrum, associated to RE emission, characterized by a partial decrease of the energy content below 1 MeV when RMPs are applied. The strength of the observed effects strongly depends on the upper-to-lower B-coil phasing, i.e. on the poloidal spectrum of the applied RMPs, which has been reconstructed including the plasma response by the code MARS-F. A crude vacuum approximation fails in the interpretation of the experimental findings: despite the relatively low β () of these discharges, a modest amplification (factor of ) of the edge kink response occurs, which has to be considered to explain the observed suppression effects. [ABSTRACT FROM AUTHOR]

Published
2018
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30. The ‘neutron deficit’ in the JET tokamak.

Author

H. Weisen, Hyun-Tae Kim, J. Strachan, S. Scott, Y. Baranov, J. Buchanan, M. Fitzgerald, D. Keeling, D.B. King, L. Giacomelli, T. Koskela, M.J. Weisen, C. Giroud, M. Maslov, W.G. Core, K.-D. Zastrow, D.B. Syme, S. Popovichev, S. Conroy, and I. Lengar

Subjects
NEUTRAL beams, NEUTRON beams, DEUTERIUM, MAGNETOHYDRODYNAMICS, TOKAMAKS
Abstract

The measured D–D neutron rate of neutral beam heated JET baseline and hybrid H-modes in deuterium is found to be between approximately 50% and 100% of the neutron rate expected from the TRANSP code, depending on the plasma parameters. A number of candidate explanations for the shortfall, such as fuel dilution, errors in beam penetration and effectively available beam power have been excluded. As the neutron rate in JET is dominated by beam–plasma interactions, the ‘neutron deficit’ may be caused by a yet unidentified form of fast particle redistribution. Modelling, which assumes fast particle transport to be responsible for the deficit, indicates that such redistribution would have to happen at time scales faster than both the slowing down time and the energy confinement time. Sawteeth and edge localised modes are found to make no significant contribution to the deficit. There is also no obvious correlation with magnetohydrodynamic activity measured using magnetic probes at the tokamak vessel walls. Modelling of fast particle orbits in the 3D fields of neoclassical tearing modes shows that realistically sized islands can only contribute a few percent to the deficit. In view of these results it appears unlikely that the neutron deficit results from a single physical process in the plasma. [ABSTRACT FROM AUTHOR]

Published
2017
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31. Conceptual design of the radial gamma ray spectrometers system for α particle and runaway electron measurements at ITER.

Author

M. Nocente, M. Tardocchi, R. Barnsley, L. Bertalot, B. Brichard, G. Croci, G. Brolatti, L. Di Pace, A. Fernandes, L. Giacomelli, I. Lengar, M. Moszynski, V. Krasilnikov, A. Muraro, R.C. Pereira, E. Perelli Cippo, D. Rigamonti, M. Rebai, J. Rzadkiewicz, and M. Salewski

Subjects
GAMMA-ray devices, PLASMA physics, TOKAMAKS, FUSION reactors, PLASMA confinement devices
Abstract

We here present the principles and main physics capabilities behind the design of the radial gamma ray spectrometers (RGRS) system for alpha particle and runaway electron measurements at ITER. The diagnostic benefits from recent advances in gamma-ray spectrometry for tokamak plasmas and combines space and high energy resolution in a single device. The RGRS system as designed can provide information on particles on a time scale of 1/10 of the slowing down time for the ITER 500 MW full power DT scenario. Spectral observations of the 3.21 and 4.44 MeV peaks from the reaction make the measurements sensitive to particles at characteristic resonant energies and to possible anisotropies of their slowing down distribution function. An independent assessment of the neutron rate by gamma-ray emission is also feasible. In case of runaway electrons born in disruptions with a typical duration of 100 ms, a time resolution of at least 10 ms for runaway electron studies can be achieved depending on the scenario and down to a current of 40 kA by use of external gas injection. We find that the bremsstrahlung spectrum in the MeV range from confined runaways is sensitive to the electron velocity space up to –40 MeV, which allows for measurements of the energy distribution of the runaway electrons at ITER. [ABSTRACT FROM AUTHOR]

Published
2017
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32. Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments.

Author

M. Schneider, T. Johnson, R. Dumont, J. Eriksson, L.-G. Eriksson, L. Giacomelli, J.-B. Girardo, T. Hellsten, E. Khilkevitch, V.G. Kiptily, T. Koskela, M. Mantsinen, M. Nocente, M. Salewski, S.E. Sharapov, A.E. Shevelev, and Contributors, JET

Subjects
CYCLOTRONS, PARTICLE accelerator design & construction, NUCLEAR fusion, PLASMA beam injection heating, FAST ions, SAWTOOTH instability, GAMMA ray spectroscopy, NEUTRON spectroscopy
Abstract

Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast ion diagnostics, showing an overall good agreement. Finally, a sawtooth activity for these experiments has been observed and interpreted using SPOT/RFOF simulations in the framework of Porcelli’s theoretical model, where NBI+ICRH accelerated ions are found to have a strong stabilizing effect, leading to monster sawteeth. [ABSTRACT FROM AUTHOR]

Published
2016
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34. Dual sightline measurements of MeV range deuterons with neutron and gamma-ray spectroscopy at JET.

Author

J. Eriksson, M. Nocente, F. Binda, C. Cazzaniga, S. Conroy, G. Ericsson, L. Giacomelli, G. Gorini, C. Hellesen, T. Hellsten, A. Hjalmarsson, A. S. Jacobsen, T. Johnson, V. Kiptily, T. Koskela, M. Mantsinen, M. Salewski, M. Schneider, S. Sharapov, and M. Skiba

Subjects
DEUTERIUM spectra, DEUTERONS, GAMMA ray spectrometer, GAMMA-ray devices, GAMMA ray spectroscopy, DEUTERIUM plasma, SPECTRUM analysis
Abstract

Observations made in a JET experiment aimed at accelerating deuterons to the MeV range by third harmonic radio-frequency (RF) heating coupled into a deuterium beam are reported. Measurements are based on a set of advanced neutron and gamma-ray spectrometers that, for the first time, observe the plasma simultaneously along vertical and oblique lines of sight. Parameters of the fast ion energy distribution, such as the high energy cut-off of the deuteron distribution function and the RF coupling constant, are determined from data within a uniform analysis framework for neutron and gamma-ray spectroscopy based on a one-dimensional model and by a consistency check among the individual measurement techniques. A systematic difference is seen between the two lines of sight and is interpreted to originate from the sensitivity of the oblique detectors to the pitch-angle structure of the distribution around the resonance, which is not correctly portrayed within the adopted one dimensional model. A framework to calculate neutron and gamma-ray emission from a spatially resolved, two-dimensional deuteron distribution specified by energy/pitch is thus developed and used for a first comparison with predictions from ab initio models of RF heating at multiple harmonics.The results presented in this paper are of relevance for the development of advanced diagnostic techniques for MeV range ions in high performance fusion plasmas, with applications to the experimental validation of RF heating codes and, more generally, to studies of the energy distribution of ions in the MeV range in high performance deuterium and deuterium-tritium plasmas. [ABSTRACT FROM AUTHOR]

Published
2015
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35. Corrigendum: Runaway electron beam generation and mitigation during disruptions at JET-ILW (2015 Nucl. Fusion 55 093013).

Author

C. Reux, V. Plyusnin, B. Alper, D. Alves, B. Bazylev, E. Belonohy, A. Boboc, S. Brezinsek, I. Coffey, J. Decker, P. Drewelow, S. Devaux, P.C. de Vries, A. Fil, S. Gerasimov, L. Giacomelli, S. Jachmich, E.M. Khilkevitch, V. Kiptily, and R. Koslowski

Subjects
ELECTRON beams, DECAY rates (Radioactivity)
Abstract

A correction to the article "Runaway Electron Beam Generation and Mitigation During Disruptions at JET-ILW" that was published in the 2015 issue is presented.

Published
2015
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36. Runaway electron beam generation and mitigation during disruptions at JET-ILW.

Author

C. Reux, V. Plyusnin, B. Alper, D. Alves, B. Bazylev, E. Belonohy, A. Boboc, S. Brezinsek, I. Coffey, J. Decker, P. Drewelow, S. Devaux, P.C. de Vries, A. Fil, S. Gerasimov, L. Giacomelli, S. Jachmich, E.M. Khilkevitch, V. Kiptily, and R. Koslowski

Subjects
TOROIDAL plasma, MAGNETOHYDRODYNAMICS, GAS injection
Abstract

Disruptions are a major operational concern for next generation tokamaks, including ITER. They may generate excessive heat loads on plasma facing components, large electromagnetic forces in the machine structures and several MA of multi-MeV runaway electrons. A more complete understanding of the runaway generation processes and methods to suppress them is necessary to ensure safe and reliable operation of future tokamaks. Runaway electrons were studied at JET-ILW showing that their generation dependencies (accelerating electric field, avalanche critical field, toroidal field, MHD fluctuations) are in agreement with current theories. In addition, vertical stability plays a key role in long runaway beam formation. Energies up to 20 MeV are observed. Mitigation of an incoming runaway electron beam triggered by massive argon injection was found to be feasible provided that the injection takes place early enough in the disruption process. However, suppressing an already accelerated runaway electron beam in the MA range was found to be difficult even with injections of more than 2 kPa.m3 high-Z gases such as krypton or xenon. This may be due to the presence of a cold background plasma weakly coupled to the runaway electron beam which prevents neutrals from penetrating in the electron beam core. Following unsuccessful mitigation attempts, runaway electron impacts on beryllium plasma-facing components were observed, showing localized melting with toroidal asymmetries. [ABSTRACT FROM AUTHOR]

Published
2015
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37. Effect of tungsten off-axis accumulation on neutral beam deposition in JET rotating plasmas.

Author

T Koskela, M Romanelli, P Belo, O Asunta, S Sipilä, M O’Mullane, L Giacomelli, S Conroy, P Mantica, M Valisa, C Angioni, T Kurki-Suonio, and contributors, JET-EFDA

Subjects
ROTATING plasmas, TUNGSTEN, PLASMA beam injection heating, PLASMA confinement, MONTE Carlo method, CENTRIFUGAL force
Abstract

Evidence for low field side accumulation of tungsten is often observed in bolometry and soft x-ray emissivities of highly rotating JET ITER-like wall (ILW) plasmas. Poloidal variation of the density of high-Z impurities, such as tungsten, in the core of NBI heated plasmas is expected from neoclassical theory due to charge displacement and parallel electric field generated by the centrifugal force. We calculate the poloidally asymmetric distribution of tungsten using fluid equations and a 1D transport simulation with the JETTO/SANCO code. Peaking of tungsten on the outboard side of the plasma is found and verified with soft x-ray and bolometry measurements. We then study the effect of a poloidally asymmetric tungsten distribution on the distribution of the NBI heat source by simulations with the Monte Carlo code ASCOT. The simulations show that the poloidally asymmetric tungsten profile redistributes the fast NBI ions radially through shifting their ionization profile and poloidally through enhanced pitch-angle scattering at high energy. The amplitude of the redistribution is in the order of 10% for the highest nW/ne ratios of ∼10−4 measured in recent JET H-mode plasmas. As a result of the scattering of the beam particles, the core heat deposition is changed less than 10%, which does not have a significant impact to the performance of JET plasmas. The modelling is in qualitative agreement with measurements by the vertical neutron camera that sees a broadening in the 2.5 MeV neutron profile when tungsten peaks on the outboard side of the plasma. [ABSTRACT FROM AUTHOR]

Published
2015
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38. Triton burn-up neutron emission in JET low current plasmas.

Author

Henrik Sjostrand, Giuseppe Gorini, S Conroy, G Ericsson, L Giacomelli, H Henriksson, A Hjalmarsson, J Kallne, D Palma, S Popovichev, M Tardocchi, M Weiszflog, and EFDA JET

Subjects
EMISSIONS (Air pollution), NEUTRONS, ATOMS, NUCLEAR physics
Abstract

In the unnumbered equation in the second column on page 2 an equals sign is missing and the subscript 0 in the denominator should be subscript f. The corrected equation is shown in the attached PDF. [ABSTRACT FROM AUTHOR]

Published
2008

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