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1. WEST full tungsten operation with an ITER grade divertor

Author

J. Bucalossi, A. Ekedahl, and the WEST Team, J. Achard, K. Afonin, O. Agullo, T. Alarcon, L. Allegretti, F. Almuhisen, H. Ancher, G. Antar, Y. Anquetin, S. Antusch, V. Anzallo, C. Arnas, J.F. Artaud, M.H. Aumeunier, S.G. Baek, X.Y. Bai, M. Balden, C. Balorin, T. Barbui, A. Barbuti, J. Barlerin, J. Barra, V. Basiuk, T. Batal, O. Baulaigue, A. Bec, M. Becoulet, E. Benoit, E. Bernard, J.M. Bernard, M. Bernert, N. Bertelli, E. Bertrand, P. Beyer, J. Bielecki, P. Bienvenu, R. Bisson, B. Bliewert, G. Bodner, S. Bose, C. Bottereau, C. Bouchand, Y. Boumendjel, F. Bouquey, C. Bourdelle, J. Bourg, S. Brezinsek, F. Brochard, C. Brun, V. Bruno, H. Bufferand, A. Bureau, S. Burles, Y. Camenen, B. Cantone, E. Caprin, M. Carole, S. Carpentier-Chouchana, G. Caulier, F. Causa, N. Cazanave, N. Chanet, O. Chellai, Y. Chen, M. Chernyshova, P. Chmielewski, W. Choe, A. Chomiczewska, G. Ciraolo, F. Clairet, J. Coenen, L. Colas, G. Colledani, J. Colnel, P. Coquillat, E. Corbel, Y. Corre, X. Courtois, T. Czarski, A. Da Ros, R. Daniel, J. Daumas, M. De Combarieu, P. De Vries, C. Dechelle, F. Deguara, R. Dejarnac, J.M. Delaplanche, L.F. Delgado-Aparicio, E. Delmas, L. Delpech, C. Desgranges, P. Devynck, J. Denis, S. Di Genova, R. Diab, A. Diallo, M. Diez, G. Dif-Pradalier, M. Dimitrova, R. Ding, T. Dittmar, L. Doceul, M. Domenes, D. Donovan, D. Douai, L. Dubus, N. Dumas, R. Dumont, F. Durand, A. Durif, F. Durodié, D. Elbeze, S. Ertmer, A. Escarguel, F. Escourbiac, B. Esposito, K. Ezato, F. Faisse, J.L. Farjon, N. Faure, N. Fedorczak, P. Fejoz, F. Felici, C. Fenzi-Bonizec, F. Ferlay, L. Ferrand, L. Fevre, M. Firdaouss, L. Fleury, D. Flouquet, T. Fonghetti, A. Gallo, X. Garbet, J. Garcia, J.L. Gardarein, L. Gargiulo, P. Garibaldi, S. Garitta, J. Gaspar, E. Gauthier, S. Gazzotti, F. Gely, J. Gerardin, G. Gervasini, E. Geulin, M. Geynet, P. Ghendrih, I. Giacalone, C. Gil, S. Ginoux, S. Girard, E. Giroux, G. Giruzzi, M. Goniche, V. Gorse, T. Gray, E. Grelier, C. Grisolia, A. Grosjean, A. Grosman, O. Grover, D. Guibert, D. Guilhem, C. Guillemaut, B. Guillermin, R. Guirlet, J.P. Gunn, Y. Gunsu, T. Gyergyek, S. Hacquin, A. Hakola, J. Harris, J.C. Hatchressian, W. Helou, P. Hennequin, C. Hernandez, L. Hijazi, J. Hillairet, T. Hirai, G.T. Hoang, C. Honoré, M. Houry, A. Huart, G. Huijsmans, P. Huynh, M. Iafrati, F. Imbeaux, N. Imbert, I. Ivanova-Stanik, P. Ivanova, R. Jalageas, A. Jamann, C. Jammes, A. Jardin, L. Jaubert, G. Jiolat, E. Joffrin, C. Johnson, A. Jonas, A. Kirschner, C.C. Klepper, M. Komm, M. Koubiti, S. Kosslow, J. Kovacic, M. Kozeiha, K. Krieger, K. Krol, I. Kudashev, B. Lacroix, L. Laguardia, V. Lamaison, V. Lapleigne, H. Laqua, C. Lau, Y. Lausenaz, R. Lé, M. Le Bohec, N. Lefevre, N. Lemoine, E. Lerche, Y. Lesourd, L. Letellier, M. Lewerentz, Y. Li, A. Liang, P. Linczuk, C. Linsmeier, M. Lipa, X. Litaudon, X. Liu, J. Llorens, T. Loarer, A. Loarte, T. Loewenhoff, G. Lombard, J. Lore, P. Lorenzetto, B. Lu, A. Lumsdaine, R. Lunsford, T. Lunt, G. Luo, P. Magaud, P. Maget, J.F. Mahieu, P. Maini, P. Malard, K. Malinowski, P. Manas, L. Manenc, V. Maquet, Y. Marandet, C. Martin, E.J. Martin, P. Martino, M. Mayer, D. Mazon, S. Mazzi, P. Messina, L. Meunier, D. Midou, G. Miglionico, Y. Mineo, M. Missirlian, R. Mitteau, B. Mitu, D. Moiraf, P. Mollard, G. Momparler, V. Moncada, T. Mondiere, C. Monti, J. Morales, M. Moreau, Ph. Moreau, Y. Moudden, G. Moureau, D. Mouyon, M. Muraglia, T. Nakano, E. Nardon, A. Neff, F. Nespoli, J. Nichols, L. Nicolas, S. Nicollet, R. Nouailletas, M. Ono, V. Ostuni, O. Paillat, C. Parish, H. Park, H. Parrat, J.Y. Pascal, B. Pegourie, F.P. Pellissier, Y. Peneliau, M. Peret, E. Pignoly, G. Pintsuk, R. Pitts, C. Pocheau, A. Podolnik, C. Portafaix, M. Poulos, P. Prochet, A. Puig Sitjes, R. Ragona, M. Rasinski, S. Ratynskaia, G. Raup, X. Regal-Mezin, C. Reux, J. Rice, M. Richou, F. Rigollet, N. Rivals, H. Roche, S. Rodrigues, J. Romazanov, G. Ronchi, C. Ruset, R. Sabot, A. Saille, R. Sakamoto, B. Salamon, F. Samaille, A. Santagiustina, B. Santraine, Y. Sarazin, O. Sauter, Y. Savoie-Peysson, L. Schiesko, M. Scholz, J.L. Schwob, E. Serre, H. Shin, S. Shiraiwa, Ja. Signoret, O. Skalli-Fettachi, P. Sogorb, Y. Song, A. Spring, P. Spuig, S. Sridhar, B. Stratton, C. Talatizi, P. Tamain, R. Tatali, Q. Tichit, A. Torre, L. Toulouse, W. Treutterer, E. Tsitrone, E.A. Unterberg, G. Urbanczyk, G. Van Rooij, N. Varadarajan, S. Vartanian, E. Velly, J.M. Verger, L. Vermare, D. Vezinet, N. Vignal, B. Vincent, S. Vives, D. Volpe, G. Wallace, E. Wang, L. Wang, Y. Wang, Y.S. Wang, T. Wauters, D. Weldon, B. Wirth, M. Wirtz, A. Wojenski, M. Xu, Q.X. Yang, H. Yang, B. Zago, R. Zagorski, B. Zhang, X.J. Zhang, X.L. Zou, and the EUROfusion Tokamak Exploitation Team

Subjects
nuclear fusion, magnetic confinement, tokamak, divertor, WEST, ITER, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The mission of WEST (tungsten-W Environment in Steady-state Tokamak) is to explore long pulse operation in a full tungsten (W) environment for preparing next-step fusion devices (ITER and DEMO) with a focus on testing the ITER actively cooled W divertor in tokamak conditions. Following the successful completion of phase 1 (2016-2021), phase 2 started in December 2022 with the lower divertor made entirely of actively cooled ITER-grade tungsten mono-blocks. A boronization prior the first plasma attempt allowed for a smooth startup with the new divertor. Despite the reduced operating window due to tungsten, rapid progress has been made in long pulse operation, resulting in discharges with a pulse length of 100 s and an injected energy of around 300 MJ per discharge. Plasma startup studies were carried out with equatorial boron nitride limiters to compare them with tungsten limiters, while Ion Cyclotron Resonance Heating assisted startup was attempted. High fluence operation in attached regime, which was the main thrust of the first campaigns, already showed the progressive build up of deposits and appearance of dust, impacting the plasma operation as the plasma fluence increased. In total, the cumulated injected energy during the first campaigns reached 43 GJ and the cumulated plasma time exceeded 5 h. Demonstration of controlled X-Point Radiator regime is also reported, opening a promising route for investigating plasma exhaust and plasma-wall interaction issues in more detached regime. This paper summarises the lessons learned from the manufacturing and the first operation of the ITER-grade divertor, describing the progress achieved in optimising operation in a full W environment with a focus on long pulse operation and plasma wall interaction.

Published
2024
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2. Global scaling of the heat transport in fusion plasmas

Author

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

Subjects
Physics, QC1-999
Abstract

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

Published
2020
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3. Model and optimization of electromagnetic filtration of metals

Author

S. Golak and R. Zagorski

Subjects
electromagnetic filtration, magnetohydrodynamics, electromagnetic buoyancy, Mining engineering. Metallurgy, TN1-997
Abstract

Electromagnetic buoyancy force causes the movement of non-conducive particles in a conducting liquid under electromagnetic field. The phenomenon allows filtration of small inclusions from molten metals. This paper presents a mathematical model of the filtration process under alternating electromagnetic field and the methodology for maximizing its efficiency.

Published
2013

4. SPIDER, the Negative Ion Source Prototype for ITER: Overview of Operations and Cesium Injection

Author

G. Serianni, E. Sartori, R. Agnello, M. Agostini, M. Barbisan, M. Bigi, M. Boldrin, M. Brombin, V. Candeloro, R. Casagrande, S. Dal Bello, M. Dan, B. P. Duteil, M. Fadone, L. Grando, P. Jain, A. Maistrello, I. Mario, R. Pasqualotto, M. Pavei, A. Pimazzoni, C. Poggi, A. Rizzolo, A. Shepherd, M. Ugoletti, P. Veltri, B. Zaniol, P. Agostinetti, D. Aprile, G. Berton, C. Cavallini, R. Cavazzana, M. Cavenago, G. Chitarin, S. Cristofaro, G. Croci, N. Cruz, M. Dalla Palma, R. Delogu, M. De Muri, M. De Nardi, S. Denizeau, F. Fellin, A. Ferro, E. Gaio, C. Gasparrini, A. Luchetta, F. Lunardon, G. Manduchi, N. Marconato, D. Marcuzzi, O. McCormack, R. Milazzo, A. Muraro, T. Patton, N. Pilan, M. Recchia, A. Rigoni-Garola, F. Santoro, B. Segalini, M. Siragusa, M. Spolaore, C. Taliercio, P. Zaccaria, R. Zagorski, L. Zanotto, M. Zaupa, M. Zuin, V. Toigo, Serianni, G, Sartori, E, Agnello, R, Agostini, M, Barbisan, M, Bigi, M, Boldrin, M, Brombin, M, Candeloro, V, Casagrande, R, Bello, S, Dan, M, Duteil, B, Fadone, M, Grando, L, Jain, P, Maistrello, A, Mario, I, Pasqualotto, R, Pavei, M, Pimazzoni, A, Poggi, C, Rizzolo, A, Shepherd, A, Ugoletti, M, Veltri, P, Zaniol, B, Agostinetti, P, Aprile, D, Berton, G, Cavallini, C, Cavazzana, R, Cavenago, M, Chitarin, G, Cristofaro, S, Croci, G, Cruz, N, Palma, M, Delogu, R, Muri, M, Nardi, M, Denizeau, S, Fellin, F, Ferro, A, Gaio, E, Gasparrini, C, Luchetta, A, Lunardon, F, Manduchi, G, Marconato, N, Marcuzzi, D, Mccormack, O, Milazzo, R, Muraro, A, Patton, T, Pilan, N, Recchia, M, Rigoni-Garola, A, Santoro, F, Segalini, B, Siragusa, M, Spolaore, M, Taliercio, C, Zaccaria, P, Zagorski, R, Zanotto, L, Zaupa, M, Zuin, M, and Toigo, V

Subjects
Nuclear and High Energy Physics, negative ion generation, RF plasma, Particle beam injection, Beam acceleration, Plasmas, Radio frequency, Cesium, Prototypes, Condensed Matter Physics, Electrodes, Particle beams
Abstract

An overview of the recent operations and the main results of cesium injection in the Source for the Production of Ions of Deuterium Extracted from Rf plasma (SPIDER) negative ion source are described in this contribution. In experiments without cesium injection, all SPIDER plants were tested to verify the basic expectations on the operational parameters (e.g., electron cooling effectiveness of magnetic filter field) and to determine its operational region. For beam properties, it was shown that the current density varies across the beam in the vertical direction. In preliminary cesium experiments, the expected increase of negative ion current and simultaneous decrease of co-extracted electrons were found, along with the influence of the control parameters (polarization of the plasma electrodes, magnetic filter field) on the SPIDER beam uniformity in the horizontal and vertical directions. It was shown that non-Gaussian tails can be identified in the angular distribution on the plane perpendicular to the beam propagation direction. Stray particles, nonhomogeneous beam and large divergence might result in unexpected heat and particle loads over ITER neutral beam injector (NBI) accelerator grids; it is the goal of SPIDER to assess and possibly to identify suitable methods for controlling these beam features. A major shutdown, planned for late 2021, to solve the issues identified during the operation and to carry out scheduled modifications, is outlined. Such improvements are expected to allow SPIDER to pursue the ITER requirements in terms of negative ion current, electron-to-ion ratio, and beam duration.

Published
2023
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5. Lessons learned after three years of SPIDER operation and the first MITICA integrated tests

Author

D. Marcuzzi, V. Toigo, M. Boldrin, G. Chitarin, S. Dal Bello, L. Grando, A. Luchetta, R. Pasqualotto, M. Pavei, G. Serianni, L. Zanotto, R. Agnello, P. Agostinetti, M. Agostini, D. Aprile, M. Barbisan, M. Battistella, G. Berton, M. Bigi, M. Brombin, V. Candela, V. Candeloro, A. Canton, R. Casagrande, C. Cavallini, R. Cavazzana, L. Cordaro, N. Cruz, M. Dalla Palma, M. Dan, A. De Lorenzi, R. Delogu, M. De Muri, M. De Nardi, S. Denizeau, M. Fadone, F. Fellin, A. Ferro, E. Gaio, C. Gasparrini, F. Gnesotto, P. Jain, A. La Rosa, D. Lopez-Bruna, R. Lorenzini, A. Maistrello, G. Manduchi, S. Manfrin, N. Marconato, I. Mario, G. Martini, R. Milazzo, T. Patton, S. Peruzzo, N. Pilan, A. Pimazzoni, C. Poggi, N. Pomaro, B. Pouradier-Duteil, M. Recchia, A. Rigoni-Garola, D. Rizzetto, A. Rizzolo, F. Santoro, E. Sartori, B. Segalini, A. Shepherd, M. Siragusa, P. Sonato, A. Sottocornola, E. Spada, S. Spagnolo, M. Spolaore, C. Taliercio, P. Tinti, P. Tomsič, L. Trevisan, M. Ugoletti, M. Valente, M. Valisa, F. Veronese, M. Vignando, P. Zaccaria, R. Zagorski, B. Zaniol, M. Zaupa, M. Zuin, M. Cavenago, D. Boilson, C. Rotti, H. Decamps, F. Geli, A. Sharma, P. Veltri, J. Zacks, M. Simon, F. Paolucci, A. Garbuglia, D. Gutierrez, A. Masiello, G. Mico, C. Labate, P. Readman, E. Bragulat, L. Bailly-Maitre, G. Gomez, G. Kouzmenko, F. Albajar, M. Kashiwagi, H. Tobari, A. Kojima, M. Murayama, S. Hatakeyama, E. Oshita, T. Maejima, N. Shibata, Y. Yamashita, K. Watanabe, N.P. Singh, M.J. Singh, H. Dhola, U. Fantz, B. Heinemann, C. Wimmer, D. Wünderlich, K. Tsumori, G. Croci, G. Gorini, A. Muraro, M. Rebai, M. Tardocchi, L. Giacomelli, D. Rigamonti, F. Taccogna, D. Bruno, M. Rutigliano, S. Longo, S. Deambrosis, E. Miorin, F. Montagner, A. Tonti, F. Panin, Marcuzzi, D, Toigo, V, Boldrin, M, Chitarin, G, Dal Bello, S, Grando, L, Luchetta, A, Pasqualotto, R, Pavei, M, Serianni, G, Zanotto, L, Agnello, R, Agostinetti, P, Agostini, M, Aprile, D, Barbisan, M, Battistella, M, Berton, G, Bigi, M, Brombin, M, Candela, V, Candeloro, V, Canton, A, Casagrande, R, Cavallini, C, Cavazzana, R, Cordaro, L, Cruz, N, Dalla Palma, M, Dan, M, De Lorenzi, A, Delogu, R, De Muri, M, De Nardi, M, Denizeau, S, Fadone, M, Fellin, F, Ferro, A, Gaio, E, Gasparrini, C, Gnesotto, F, Jain, P, La Rosa, A, Lopez-Bruna, D, Lorenzini, R, Maistrello, A, Manduchi, G, Manfrin, S, Marconato, N, Mario, I, Martini, G, Milazzo, R, Patton, T, Peruzzo, S, Pilan, N, Pimazzoni, A, Poggi, C, Pomaro, N, Pouradier-Duteil, B, Recchia, M, Rigoni-Garola, A, Rizzetto, D, Rizzolo, A, Santoro, F, Sartori, E, Segalini, B, Shepherd, A, Siragusa, M, Sonato, P, Sottocornola, A, Spada, E, Spagnolo, S, Spolaore, M, Taliercio, C, Tinti, P, Tomsic, P, Trevisan, L, Ugoletti, M, Valente, M, Valisa, M, Veronese, F, Vignando, M, Zaccaria, P, Zagorski, R, Zaniol, B, Zaupa, M, Zuin, M, Cavenago, M, Boilson, D, Rotti, C, Decamps, H, Geli, F, Sharma, A, Veltri, P, Zacks, J, Simon, M, Paolucci, F, Garbuglia, A, Gutierrez, D, Masiello, A, Mico, G, Labate, C, Readman, P, Bragulat, E, Bailly-Maitre, L, Gomez, G, Kouzmenko, G, Albajar, F, Kashiwagi, M, Tobari, H, Kojima, A, Murayama, M, Hatakeyama, S, Oshita, E, Maejima, T, Shibata, N, Yamashita, Y, Watanabe, K, Singh, N, Singh, M, Dhola, H, Fantz, U, Heinemann, B, Wimmer, C, Wunderlich, D, Tsumori, K, Croci, G, Gorini, G, Muraro, A, Rebai, M, Tardocchi, M, Giacomelli, L, Rigamonti, D, Taccogna, F, Bruno, D, Rutigliano, M, Longo, S, Deambrosis, S, Miorin, E, Montagner, F, Tonti, A, and Panin, F

Subjects
Accelerator Physics (physics.acc-ph), iter, Mechanical Engineering, FOS: Physical sciences, nbtf, neutral beam injector, mitica, Physics - Plasma Physics, Plasma Physics (physics.plasm-ph), Nuclear Energy and Engineering, Physics - Accelerator Physics, General Materials Science, spider, Civil and Structural Engineering
Abstract

ITER envisages the use of two heating neutral beam injectors plus an optional one as part of the auxiliary heating and current drive system, to reach the desired performances during its various phases of operation. The 16.5 MW expected neutral beam power per injector is several notches higher than worldwide existing facilities.In order to enable such development, a Neutral Beam Test Facility (NBTF) was established at Consorzio RFX, exploiting the synergy of two test beds, called SPIDER and MITICA. SPIDER is dedicated developing and char-acterizing large efficient negative ion sources at relevant parameters in ITER-like conditions: source and accel-erator located in the same vacuum where the beam propagates, immunity to electromagnetic interferences of multiple radio-frequency (RF) antennas, avoidance of RF-induced discharges on the outside of the source. Three years of experiments on SPIDER have addressed to the necessary design modifications to enable full perfor-mances. The source is presently under a long shut-down phase to incorporate learnings from the experimental campaign, in particular events/issues occurred during operation, which led to the identification of improvement opportunities/necessities (e.g. RF discharges, local burns, water leaks, other damages, configuration/design upgrades to maximize chances/margin to quest target parameters).Parallelly, developments on MITICA, the full-scale prototype of the ITER Neutral Beam Injector (NBI) featuring a 1 MV accelerator and ion neutralization, are underway including manufacturing of the beam source, accel-erator and the beam line components, while power supplies and auxiliary plants, already installed, are under final testing and commissioning.Integration, commissioning and tests of the 1 MV power supplies are essential for this first-of-kind system, unparalleled both in research and industry field. 1.2 MV dc insulating tests of high voltage components were successfully completed. The integrated test to confirm 1 MV output by combining invertor systems, DC gener-ators and transmission lines extracted errors/accidents in some components. To realize a concrete system for ITER, said events have been addressed and solutions for the repair and the improvement of the system were developed.Hence, NBTF is emerging as a necessary facility, due to the large gap with existing injectors, effectively dedicated to identify issues and find solutions to enable successful ITER NBI operations in a time bound fashion. The lessons learned during the implementation on NBTF and future perspectives are here discussed.

Published
2023
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6. On the road to ITER NBIs: SPIDER improvement after first operation and MITICA construction progress

Author

M. Tardocchi, G. Mico, Hitesh Patel, V. Antoni, A. Garbuglia, A. Masiello, Emanuele Sartori, L. Giacomelli, M. Brombin, F. Geli, A. De Lorenzi, Pierluigi Veltri, Piero Agostinetti, Gabriele Manduchi, S. Cristofaro, T. Maejima, D. Bruno, F. Paolucci, Marica Rebai, L. Cordaro, M. Zaupa, B. Pouradier-Duteil, S. Denizeau, M. Vignando, R. Lorenzini, Y. Yamashita, M. Dan, R. Casagrande, D. Lopez-Bruna, Federica Bonomo, R. Zagorski, M. Siragusa, M. Zuin, A. Rigoni-Garola, V. Candeloro, Daniel Gutierrez, H. Decamps, C. Taliercio, Loris Zanotto, F. Fellin, C. Rotti, M. Fadone, R. Delogu, M. Valente, M. Bigi, A. Canton, Gabriele Croci, R. Agnello, A. Pimazzoni, Bernd Heinemann, Emilio Martines, O. McCormack, M. Dalla Palma, Kazuhiro Watanabe, J. Graceffa, Nicola Pilan, Simone Peruzzo, Vanni Toigo, E. Oshita, A. Rizzolo, Elena Gaio, D. Aprile, M. Dremel, M. De Muri, B. Zaniol, R. Milazzo, C. Cavallini, Silvia Spagnolo, Gianluigi Serianni, N. Cruz, A. Sottocornola, Claudia Gasparrini, Hiroyuki Tobari, L. Trevisan, Namita Singh, P. Tomsic, T. Patton, F. Gasparini, F. Taccogna, Diego Marcuzzi, Atsushi Kojima, E. Spada, A. Muraro, Ursel Fantz, M. Pavei, A.K. Chakraborty, Francesco Gnesotto, A. Ferro, S. Konno, Tullio Bonicelli, Roberto Cavazzana, Giuseppe Chitarin, Nicolò Marconato, Giuseppe Gorini, Adriano Luchetta, A. Maistrello, A. Zamengo, C. Poggi, Marco D’Arienzo, N. Pomaro, F. Panin, A. Rousseau, Monica Spolaore, G. Berton, J.F. Moreno, W. Kraus, S. Dal Bello, M. Battistella, P. Tinti, G. Kouzmenko, D. Boilson, Piergiorgio Sonato, Marco Cavenago, C. Wimmer, M. J. Singh, M. Rutigliano, P. Jain, Pierluigi Zaccaria, M. Ugoletti, Marco Boldrin, D. Rigamonti, Katsuyoshi Tsumori, S. Manfrin, D. Wünderlich, Gwenael Fubiani, Muriel Simon, G. Martini, G. Agarici, Mieko Kashiwagi, D. Terranova, Marco Barbisan, S. Martini, M. Urbani, Luca Grando, Roberto Pasqualotto, J. Zacks, A. Tonti, M. Recchia, C. Labate, Matteo Agostini, P.B. Krastev, V. Pilard, G. Gomez, A. Shepherd, Toigo, V, Marcuzzi, D, Serianni, G, Boldrin, M, Chitarin, G, Bello, S, Grando, L, Luchetta, A, Pasqualotto, R, Zaccaria, P, Zanotto, L, Agnello, R, Agostinetti, P, Agostini, M, Antoni, V, Aprile, D, Barbisan, M, Battistella, M, Berton, G, Bigi, M, Brombin, M, Candeloro, V, Canton, A, Casagrande, R, Cavallini, C, Cavazzana, R, Cordaro, L, Cruz, N, Palma, M, Dan, M, De Lorenzi, A, Delogu, R, De Muri, M, Denizeau, S, Fadone, M, Fellin, F, Ferro, A, Gaio, E, Gasparini, F, Gasparrini, C, Gnesotto, F, Jain, P, Krastev, P, Lopez-Bruna, D, Lorenzini, R, Maistrello, A, Manduchi, G, Manfrin, S, Marconato, N, Martines, E, Martini, G, Martini, S, Milazzo, R, Patton, T, Pavei, M, Peruzzo, S, Pilan, N, Pimazzoni, A, Poggi, C, Pomaro, N, Pouradier-Duteil, B, Recchia, M, Rigoni-Garola, A, Rizzolo, A, Sartori, E, Shepherd, A, Siragusa, M, Sonato, P, Sottocornola, A, Spada, E, Spagnolo, S, Spolaore, M, Taliercio, C, Terranova, D, Tinti, P, Tomsic, P, Trevisan, L, Ugoletti, M, Valente, M, Vignando, M, Zagorski, R, Zamengo, A, Zaniol, B, Zaupa, M, Zuin, M, Cavenago, M, Boilson, D, Rotti, C, Veltri, P, Decamps, H, Dremel, M, Graceffa, J, Geli, F, Urbani, M, Zacks, J, Bonicelli, T, Paolucci, F, Garbuglia, A, Agarici, G, Gomez, G, Gutierrez, D, Kouzmenko, G, Labate, C, Masiello, A, Mico, G, Moreno, J, Pilard, V, Rousseau, A, Simon, M, Kashiwagi, M, Tobari, H, Watanabe, K, Maejima, T, Kojima, A, Oshita, E, Yamashita, Y, Konno, S, Singh, M, Chakraborty, A, Patel, H, Singh, N, Fantz, U, Bonomo, F, Cristofaro, S, Heinemann, B, Kraus, W, Wimmer, C, Wunderlich, D, Fubiani, G, Tsumori, K, Croci, G, Gorini, G, Mccormack, O, Muraro, A, Rebai, M, Tardocchi, M, Giacomelli, L, Rigamonti, D, Taccogna, F, Bruno, D, Rutigliano, M, D'Arienzo, M, Tonti, A, and Panin, F

Subjects
Tokamak, Nuclear engineering, design, 7. Clean energy, 01 natural sciences, negative ion source, 010305 fluids & plasmas, law.invention, ITER neutral beam injector, ITER neutral beam injectors, Negative ion beam, Negative ion source, law, iter neutral beam injectors, 0103 physical sciences, General Materials Science, 010306 general physics, Civil and Structural Engineering, Dummy load, Magnetic filter, negative ion beam, Mechanical Engineering, Injector, Beam optics, Power (physics), Nuclear Energy and Engineering, Environmental science, Beam (structure), Voltage
Abstract

To reach fusion conditions and control the plasma configuration in ITER, the next step in tokamak fusion research, two neutral beam injectors (NBIs) will supply 16.5 MW each, by neutralizing accelerated negative hydrogen or deuterium ions. The requirements of ITER NBIs (40A/1 MeV D- ions for ≤1 h, 46A/870 keV H- ions for ≤1000 s) have never been simultaneously attained. So in the Neutral Beam Test Facility (NBTF, Consorzio RFX, Italy) the operation of the full-scale ITER NBI prototype (MITICA) will be tested and optimised up to full performances, focussing on accelerator (including voltage holding), beam optics, neutralisation, residual ion removal. The NBTF includes also the full-scale prototype of the ITER NBI source with 100 keV particle energy (SPIDER), for early investigation of: negative ion production and extraction, source uniformity, negative ion current density and beam optics. This paper will describe the main results of the first two years of SPIDER operation, devoted to characterizing plasma and beam parameters, including investigation of RF-plasma coupling efficiency and magnetic filter field effectiveness in reducing co-extracted electrons. SPIDER is progressing towards the first caesium injection, which aims at increasing the negative ion density. A major shutdown, planned for 2021, to solve the issues identified during the operation and to carry out programmed modifications, will be outlined. The installation of each MITICA power supply and auxiliary system is completed; in-vessel mechanical components are under procurement by Fusion for Energy (F4E). Integration, commissioning and test of the power supplies, procured by F4E and QST, as the Japanese Domestic Agency (JADA), will be presented. In particular, 1.0MV insulating tests were carried out step-by-step and successfully completed. In 2020 integrated tests of the power supplies on the accelerator dummy load started, including the assessment of their resilience to accelerator grid breakdowns using a short-circuit device located in vacuum. The aggressive programme, to validate the NBI design at NBTF and to meet ITER schedule (requiring NBIs in operation in 2032), will be outlined. Unfortunately, in 2020 the coronavirus disease infection affected the NBTF activities. A solution to proceed with integrated power tests despite the coronavirus is presented.

Published
2021
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7. How do eye size and facet lens size vary by age and sex inAcheta domesticus?

Author

Emily R. Zagorski and Justin W. Merry

Subjects
musculoskeletal diseases, Facet (geometry), genetic structures, biology, media_common.quotation_subject, General Engineering, Insect, Anatomy, Nocturnal, musculoskeletal system, biology.organism_classification, Age and sex, eye diseases, medicine.anatomical_structure, Ommatidium, Cricket, Acheta, Lens (anatomy), medicine, sense organs, media_common
Abstract

Vision is essential to interactions with the environment and survival of many animals. House crickets, Acheta domesticus, are nocturnal insects with compound apposition eyes, and thus may have a specialized visual system selected for low-light vision. Here, an analysis of regional variation in facet diameter around the eye of a cricket was conducted. Eye surface area was estimated and facet diameter was spot-sampled across the eyes of 13 adults and 13 juveniles. Juveniles had smaller facets than adults, and there was significant variation among eye regions in facet size. Specifically, larger facets were found in the posterior eye region. Overall, facets were large given the size of this animal's eye, which is consistent with what one might expect from a nocturnal insect under selection for high sensitivity. Furthermore, juveniles had proportionally larger facets than adults, which may indicate that the insects maximize the sensitivity of their ommatidia early in development, prior to increasing ...

Published
2014
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8. Numerical Scaling with the COREDIV Code of JET Discharges with the ITER-Like Wall

Author

C. Giroud, Jet-Efda Contributors, Giuseppe Telesca, Irena Ivanova-Stanik, S. Brezinsek, G. Van Ooost, and R. Zagorski

Subjects
Physics, Electron density, Range (particle radiation), Jet (fluid), Flux, Radiation, Condensed Matter Physics, 01 natural sciences, Electromagnetic radiation, 010305 fluids & plasmas, Core (optical fiber), 0103 physical sciences, Electron temperature, Atomic physics, 010306 general physics
Abstract

After the code parameters have been fixed by the numerical modeling of a well diagnosed JET pulse, the electron density and the input power have been changed, resulting in 4 density scans (〈ne〉 in the range 3.8 – 8.2 x 1019m-3) at Pin = 17, 22, 27, 32 MW. At any given power level, W flux decreases with increasing 〈ne〉 as a consequence of the decrease in Te at the target plates. Also the W concentration in the core (cW) decreases, but this not necessarily leads to reduced core radiation. Indeed, while at high Pin the core radiation decreases with density, at low Pin it increases. At high 〈ne〉 the increase in the input power leads to enhanced PradPrad, leaving, however, nearly unchanged the power radiated fraction frad Indeed, the increase in frad withPin is observed only at low 〈ne〉, up to a level of about frad = 0.4. These numerical results, linked to the non-linear self-consistent physics of W production and transport, suggest the best conditions are achieved when the level of the electron density is adapted to the level of the available Pin. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Published
2014
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9. Overview of ASDEX upgrade results in view of ITER and DEMO

Author

H. Zohm, E. Alessi, C. Angioni, N. Arden, V. Artigues, M. Astrain, O. Asunta, M. Balden, V. Bandaru, A. Banon Navarro, M. Bauer, A. Bergmann, M. Bergmann, J. Bernardo, M. Bernert, A. Biancalani, R. Bielajew, R. Bilato, G. Birkenmeier, T. Blanken, V. Bobkov, A. Bock, L. Bock, T. Body, T. Bolzonella, N. Bonanomi, A. Bortolon, B. Böswirth, C. Bottereau, A. Bottino, H. van den Brand, M. Brenzke, S. Brezinsek, D. Brida, F. Brochard, J. Buchanan, A. Buhler, A. Burckhart, Y. Camenen, B. Cannas, P. Cano Megías, D. Carlton, M. Carr, P. Carvalho, C. Castaldo, A. Castillo Castillo, A. Cathey, M. Cavedon, C. Cazzaniga, C. Challis, A. Chankin, A. Chomiczewska, C. Cianfarani, F. Clairet, S. Coda, R. Coelho, J.W. Coenen, L. Colas, G. Conway, S. Costea, D. Coster, T. Cote, A.J. Creely, G. Croci, D.J. Cruz Zabala, G. Cseh, I. Cziegler, O. D’Arcangelo, A. Dal Molin, P. David, C. Day, M. de Baar, P. de Marné, R. Delogu, P. Denner, A. Di Siena, M. Dibon, J.J. Dominguez-Palacios Durán, D. Dunai, M. Dreval, M. Dunne, B.P. Duval, R. Dux, T. Eich, S. Elgeti, A. Encheva, B. Esposito, E. Fable, M. Faitsch, D. Fajardo Jimenez, U. Fantz, M. Farnik, H. Faugel, F. Felici, O. Ficker, A. Figueredo, R. Fischer, O. Ford, L. Frassinetti, M. Fröschle, G. Fuchert, J.C. Fuchs, H. Fünfgelder, S. Futatani, K. Galazka, J. Galdon-Quiroga, D. Gallart Escolà, A. Gallo, Y. Gao, S. Garavaglia, M. Garcia Muñoz, B. Geiger, L. Giannone, S. Gibson, L. Gil, E. Giovannozzi, I. Girka, O. Girka, T. Gleiter, S. Glöggler, M. Gobbin, J.C. Gonzalez, J. Gonzalez Martin, T. Goodman, G. Gorini, T. Görler, D. Gradic, G. Granucci, A. Gräter, G. Grenfell, H. Greuner, M. Griener, M. Groth, O. Grover, A. Gude, L. Guimarais, S. Günter, D. Hachmeister, A.H. Hakola, C. Ham, T. Happel, N. den Harder, G. Harrer, J. Harrison, V. Hauer, T. Hayward-Schneider, B. Heinemann, P. Heinrich, T. Hellsten, S. Henderson, P. Hennequin, M. Herschel, S. Heuraux, A. Herrmann, E. Heyn, F. Hitzler, J. Hobirk, K. Höfler, S. Hörmann, J.H. Holm, M. Hölzl, C. Hopf, L. Horvath, T. Höschen, A. Houben, A. Hubbard, A. Huber, K. Hunger, V. Igochine, M. Iliasova, J. Illerhaus, K. Insulander Björk, C. Ionita-Schrittwieser, I. Ivanova-Stanik, S. Jachmich, W. Jacob, N. Jaksic, A. Jansen van Vuuren, F. Jaulmes, F. Jenko, T. Jensen, E. Joffrin, A. Kallenbach, J. Kalis, A. Kappatou, J. Karhunen, C.-P. Käsemann, S. Kasilov, Y. Kazakov, A. Kendl, W. Kernbichler, E. Khilkevitch, M. Kircher, A. Kirk, S. Kjer Hansen, V. Klevarova, F. Klossek, G. Kocsis, M. Koleva, M. Komm, M. Kong, A. Krämer-Flecken, M. Krause, I. Krebs, A. Kreuzeder, K. Krieger, O. Kudlacek, D. Kulla, T. Kurki-Suonio, B. Kurzan, B. Labit, K. Lackner, F. Laggner, A. Lahtinen, P. Lainer, P.T. Lang, P. Lauber, M. Lehnen, L. Leppin, E. Lerche, N. Leuthold, L. Li, J. Likonen, O. Linder, H. Lindl, B. Lipschultz, Y. Liu, Z. Lu, T. Luda Di Cortemiglia, N.C. Luhmann, T. Lunt, A. Lyssoivan, T. Maceina, J. Madsen, A. Magnanimo, H. Maier, J. Mailloux, R. Maingi, O. Maj, E. Maljaars, V. Maquet, A. Mancini, A. Manhard, P. Mantica, M. Mantsinen, P. Manz, M. Maraschek, C. Marchetto, M. Markl, L. Marrelli, P. Martin, F. Matos, M. Mayer, P.J. McCarthy, R. McDermott, G. Meng, R. Merkel, A. Merle, H. Meyer, M. Michelini, D. Milanesio, V. Mitterauer, P. Molina Cabrera, M. Muraca, F. Nabais, V. Naulin, R. Nazikian, R.D. Nem, R. Neu, A.H. Nielsen, S.K. Nielsen, T. Nishizawa, M. Nocente, I. Novikau, S. Nowak, R. Ochoukov, J. Olsen, P. Oyola, O. Pan, G. Papp, A. Pau, G. Pautasso, C. Paz-Soldan, M. Peglau, E. Peluso, P. Petersson, C. Piron, U. Plank, B. Plaum, B. Plöckl, V. Plyusnin, G. Pokol, E. Poli, A. Popa, L. Porte, J. Puchmayr, T. Pütterich, L. Radovanovic, M. Ramisch, J. Rasmussen, G. Ratta, S. Ratynskaia, G. Raupp, A. Redl, D. Réfy, M. Reich, F. Reimold, D. Reiser, M. Reisner, D. Reiter, B. Rettino, T. Ribeiro, D. Ricci, R. Riedl, J. Riesch, J.F. Rivero Rodriguez, G. Rocchi, P. Rodriguez-Fernandez, V. Rohde, G. Ronchi, M. Rott, M. Rubel, D.A. Ryan, F. Ryter, S. Saarelma, M. Salewski, A. Salmi, O. Samoylov, L. Sanchis Sanchez, J. Santos, O. Sauter, G. Schall, A. Schlüter, J. Scholte, K. Schmid, O. Schmitz, P.A. Schneider, R. Schrittwieser, M. Schubert, C. Schuster, N. Schwarz, T. Schwarz-Selinger, J. Schweinzer, F. Sciortino, O. Seibold-Benjak, A. Shabbir, A. Shalpegin, S. Sharapov, U. Sheikh, A. Shevelev, G. Sias, M. Siccinio, B. Sieglin, A. Sigalov, A. Silva, C. Silva, D. Silvagni, J. Simpson, S. Sipilä, A. Snicker, E. Solano, C. Sommariva, C. Sozzi, M. Spacek, G. Spizzo, M. Spolaore, A. Stegmeir, M. Stejner, D. Stieglitz, J. Stober, U. Stroth, E. Strumberger, G. Suarez Lopez, W. Suttrop, T. Szepesi, B. Tál, T. Tala, W. Tang, G. Tardini, M. Tardocchi, D. Terranova, M. Teschke, E. Thorén, W. Tierens, D. Told, W. Treutterer, G. Trevisan, M. Tripský, P. Ulbl, G. Urbanczyk, M. Usoltseva, M. Valisa, M. Valovic, S. van Mulders, M. van Zeeland, F. Vannini, B. Vanovac, P. Varela, S. Varoutis, T. Verdier, G. Verdoolaege, N. Vianello, J. Vicente, T. Vierle, E. Viezzer, I. Voitsekhovitch, U. von Toussaint, D. Wagner, X. Wang, M. Weiland, D. Wendler, A.E. White, M. Willensdorfer, B. Wiringer, M. Wischmeier, R. Wolf, E. Wolfrum, Q. Yang, C. Yoo, Q. Yu, R. Zagórski, I. Zammuto, T. Zehetbauer, W. Zhang, W. Zholobenko, A. Zibrov, M. Zilker, C.F.B. Zimmermann, A. Zito, S. Zoletnik, the EUROfusion Tokamak Exploitation Team, and the ASDEX Upgrade Team

Subjects
tokamak, MHD stability, transport modelling, radiative exhaust, disruption physics, ELM free scenarios, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Experiments on ASDEX Upgrade (AUG) in 2021 and 2022 have addressed a number of critical issues for ITER and EU DEMO. A major objective of the AUG programme is to shed light on the underlying physics of confinement, stability, and plasma exhaust in order to allow reliable extrapolation of results obtained on present day machines to these reactor-grade devices. Concerning pedestal physics, the mitigation of edge localised modes (ELMs) using resonant magnetic perturbations (RMPs) was found to be consistent with a reduction of the linear peeling-ballooning stability threshold due to the helical deformation of the plasma. Conversely, ELM suppression by RMPs is ascribed to an increased pedestal transport that keeps the plasma away from this boundary. Candidates for this increased transport are locally enhanced turbulence and a locked magnetic island in the pedestal. The enhanced D-alpha (EDA) and quasi-continuous exhaust (QCE) regimes have been established as promising ELM-free scenarios. Here, the pressure gradient at the foot of the H-mode pedestal is reduced by a quasi-coherent mode, consistent with violation of the high-n ballooning mode stability limit there. This is suggestive that the EDA and QCE regimes have a common underlying physics origin. In the area of transport physics, full radius models for both L- and H-modes have been developed. These models predict energy confinement in AUG better than the commonly used global scaling laws, representing a large step towards the goal of predictive capability. A new momentum transport analysis framework has been developed that provides access to the intrinsic torque in the plasma core. In the field of exhaust, the X-Point Radiator (XPR), a cold and dense plasma region on closed flux surfaces close to the X-point, was described by an analytical model that provides an understanding of its formation as well as its stability, i.e., the conditions under which it transitions into a deleterious MARFE with the potential to result in a disruptive termination. With the XPR close to the divertor target, a new detached divertor concept, the compact radiative divertor, was developed. Here, the exhaust power is radiated before reaching the target, allowing close proximity of the X-point to the target. No limitations by the shallow field line angle due to the large flux expansion were observed, and sufficient compression of neutral density was demonstrated. With respect to the pumping of non-recycling impurities, the divertor enrichment was found to mainly depend on the ionisation energy of the impurity under consideration. In the area of MHD physics, analysis of the hot plasma core motion in sawtooth crashes showed good agreement with nonlinear 2-fluid simulations. This indicates that the fast reconnection observed in these events is adequately described including the pressure gradient and the electron inertia in the parallel Ohm’s law. Concerning disruption physics, a shattered pellet injection system was installed in collaboration with the ITER International Organisation. Thanks to the ability to vary the shard size distribution independently of the injection velocity, as well as its impurity admixture, it was possible to tailor the current quench rate, which is an important requirement for future large devices such as ITER. Progress was also made modelling the force reduction of VDEs induced by massive gas injection on AUG. The H-mode density limit was characterised in terms of safe operational space with a newly developed active feedback control method that allowed the stability boundary to be probed several times within a single discharge without inducing a disruptive termination. Regarding integrated operation scenarios, the role of density peaking in the confinement of the ITER baseline scenario (high plasma current) was clarified. The usual energy confinement scaling ITER98( p,y ) does not capture this effect, but the more recent H20 scaling does, highlighting again the importance of developing adequate physics based models. Advanced tokamak scenarios, aiming at large non-inductive current fraction due to non-standard profiles of the safety factor in combination with high normalised plasma pressure were studied with a focus on their access conditions. A method to guide the approach of the targeted safety factor profiles was developed, and the conditions for achieving good confinement were clarified. Based on this, two types of advanced scenarios (‘hybrid’ and ‘elevated’ q -profile) were established on AUG and characterised concerning their plasma performance.

Published
2024
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10. COREDIV simulations of D and D–T high current–high power Baseline pulses in JET-ITER like wall

Author

G. Telesca, A.R. Field, I. Ivanova-Stanik, S. Brezinsek, A. Chomiczewska, D. Frigione, L. Garzotti, E. Kowalska-Strzeciwilk, P. Lomas, J. Mailloux, G. Pucella, F. Rimini, D. Van Eester, R. Zagórski, and JET Contributors

Subjects
JET tokamak, COREDIV, modelling, impurity transport, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

The two best performing pulses of the so called ITER-Baseline scenario ( I _p = 3.5 MA and P _in ≈ 35 MW) of JET-ITER like wall, one in deuterium (D) the other in deuterium–tritium (D–T) plasma are examined and compared in this study. Generally, the D–T Baseline pulses exhibit an electron density level higher than the D pulses and the plasma energy is higher than in the comparable D pulses by up to 20%, reaching about 12 MJ in the pulse studied here. In contrast with the D pulses, the D–T pulses are often characterised by the increase in time of the radiated power in the mantle region (0.70 < ρ < 0.95), which may lead to the loss of the edge localised mode activity when the threshold H–L transition power is approached and to the subsequent plasma disruption due to excessive radiation. In this study we try to identify the physical mechanisms responsible for this behaviour using the available experimental data (principally the total radiated power from the bolometry) and the results of the fluid COREDIV model (1D in the core, 2D in the scrape-off-layer (SOL)), self-consistent with respect to core-SOL and also to main plasma-impurities. In fact, the loss of power caused by impurity radiation affects the temperature profile and finally the power to the divertor plate. The electron density and temperature profiles are numerically reconstructed as well as the radiated power density profiles, indicating no major difference in impurity transport in D and D–T. Indeed, the impurity transport coefficients used in COREDIV to match the experimental radiated power profiles are similar in the two pulses. The computed tungsten sources and densities are lower in the D–T pulse and the divertor impurity retention capability is a little better in the D–T pulse, indicatinga stronger collisional drag force in the SOL. The higher electron density and the broadening of its profile are the main cause of the observed increase of the radiated power in the D–T pulse.

Published
2024
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11. EUROfusion Integrated Modelling (EU-IM) Capabilities and Selected Physics Applications

Author

Falchetto G.L., M.I. Airila, A. Alberto Morillas, E. Andersson Sundén, T. Aniel, J.-F. Artaud, O. Asunta, C.V. Atanasiu, M. Baelmans, V. Basiuk, R. Bilato, M. Blommaert, D. Borodin, C. Boulbe, S. Briguglio, J. Citrin, R. Coelho, S. Conroy, D. Coster, V. Doriæ, R. Dumont, E. Fable, B. Faugeras, J. Ferreira, L. Figini, A. Figueiredo, G. Fogaccia, C. Fuchs, E. Giovannozzi, V. Goloborod'ko, O. Hoenen, Ph. Huynh, F. Imbeaux, I. Ivanova-Stanik, T. Johnson, D. Kalupin, L. Kos, E. Lerche, J. Madsen, O. Maj, G. Manduchi, M. Mantsinen, Y. Marandet, S. Matejcik, R. Mayo-Garcia, P.J. McCarthy, A. Merle, E. Nardon, A.H. Nielsen, S. Nowak, M. O'Mullane, M. Owsiak, V. Pais, B. Palak, G. Pelka, M. Plociennik, G.I. Pokol, D. Poljak, H. Radhakrishnan, H. Reimerdes, D. Reiser, J. Romazanov, P. Rodrigues, X. Saez, D. Samaddar, O. Sauter, K. Schmid, B.D. Scott, S. ?esni?, J. Signoret, S.K. Sipilä, R. Stankiewicz, P. Strand, E. Suchkov, A. Susnjara, G. Szepesi, D. Tegnered, K. Tokési, D. Tskhakaya, J. Urban, P. Vallejos, D. Van Eester, L. Villard, F. Villone, B. Viola, G. Vlad, E. Westerhof, D. Yadykin, R. Zagorski, F. Zaitsev, T. Zok, W. Zwingmann, S. Äkäslompolo, the ASDEX Upgrade Team, and the EUROfusion-IM Team

Subjects
Physics Applications, EUROfusion Integrated Modelling, EU-IM
Abstract

Recent developments and achievements of the EUROfusion Code Development for Integrated Modelling project (WPCD), which aim is to provide a validated integrated modelling suite for the simulation and prediction of complete plasma discharges in any tokamak, are presented. WPCD develops generic complex integrated simulations, workflows, for physics applications, using the standardized European Integrated Modelling (EU-IM) framework. Selected physics applications of EU-IM workflows are illustrated in this paper.

Published
2016

12. Self-consistent modeling of impurity seeded JET advanced tokamak scenarios

Author

R. Zagorski, K. McCormick, G. Telesca, W. Fundamenski, Jet-Efda Contributors, M. Beurskens, and G. Arnoux

Subjects
Nuclear and High Energy Physics, Jet (fluid), Tokamak, Computer simulation, Divertor, chemistry.chemical_element, Mechanics, Plasma, Fusion power, law.invention, Nuclear physics, Neon, Nuclear Energy and Engineering, Nuclear reactor core, chemistry, law, General Materials Science
Abstract

The influence of neon and nitrogen seeding on the divertor heat load in JET tokamak is studied in terms of the numerical simulations of the whole device by the self-consistent core–edge code COREDIV and results are presented for advanced tokamak scenarios. First, the code has been applied to simulate two JET shots (#69980, #69987) characterized by different radiation levels. With this basis the code is used next to provide guidance for the JET experiments in terms of: effects on the heat load at the target plates for various x-point positions with respect to the target plates, and the effect of higher plasma and separatrix density, as well as effects of pure or mixed Ne/ N 2 -seeding.

Published
2009
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13. Numerical investigations of plasma parameters in the COMPASS tokamak

Author

R. Zagorski, E. Havlickova, and Radomir Panek

Subjects
Physics, Tokamak, Physics and Astronomy (miscellaneous), COMPASS tokamak, Plasma parameters, business.industry, Frame (networking), Edge region, Plasma, Condensed Matter Physics, law.invention, Boundary layer, Optics, Physics::Plasma Physics, law, Physics::Space Physics, business
Abstract

A numerical investigation of plasma parameters in a diverter configuration of COMPASS tokamak is presented. The plasma parameters in the device are analyzed in the frame of the self-consistent description of the central plasma and edge region. The possibility of achieving high recycling and detached regimes in the boundary layer of the COMPASS tokamak is discussed.

Published
2008
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14. 3D edge energy transport in stellarator configurations

Author

Xavier Bonnin, N. McTaggart, T. B. Kaiser, Maxim Umansky, A. Runov, R. Zagorski, T.D. Rognlien, and R. Schneider

Subjects
Physics, Nuclear and High Energy Physics, Ergodicity, Finite difference method, Plasma diffusion, Numerical diffusion, Computational physics, law.invention, Unstructured grid, Nuclear Energy and Engineering, law, General Materials Science, Statistical physics, Diffusion (business), Convection–diffusion equation, Stellarator
Abstract

The finite difference discretization method is used to solve the electron energy transport equation in complex 3D edge geometries using an unstructured grid. This grid is generated by field-line tracing to separate the radial and parallel fluxes and minimize the numerical diffusion connected with the strong anisotropy of the system. The influence of ergodicity on the edge plasma transport in the W7-X stellarator is investigated in this paper. Results show that the combined effect of ergodicity and the radial plasma diffusion leads to the efficient smoothing of the temperature profiles in the finite-β case.

Published
2005
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15. Transport modelling for ergodic configurations

Author

R. Zagorski, Xavier Bonnin, Sergei Kasilov, R. Schneider, D. Reiter, A. Runov, and N. McTaggart

Subjects
Physics, Nuclear and High Energy Physics, Parallel transport, Discretization, Ergodicity, Mathematical analysis, Monte Carlo method, Finite difference, Finite difference method, Numerical diffusion, Condensed Matter Physics, ddc:530, Statistical physics, Convection–diffusion equation
Abstract

The effect of ergodization, either by additional coils like in TEXTOR-dynamic ergodic divertor (DED) or by intrinsic plasma effects like in W7-X, defines the need for transport models that are able to describe the ergodic configuration properly. A prerequisite for this is the concept of local magnetic coordinates allowing a correct discretization with minimized numerical errors. For these coordinates the appropriate full metric tensor has to be known. To study the transport in complex edge geometries (in particular for W7-X) two possible methods are used. First, a finite-difference discretization of the transport equations on a custom-tailored grid in local magnetic coordinates is used. This grid is generated by field-line tracing to guarantee an exact discretization of the dominant parallel transport (thus also minimizing the numerical diffusion problem). The perpendicular fluxes are then interpolated in a plane (a toroidal cut), where the interpolation problem for a quasi-isotropic system has to be solved by a constrained Delaunay triangulation (keeping the structural information for magnetic surfaces if they exist) and discretization. All toroidal terms are discretized by finite differences. Second, a Monte Carlo transport model originally developed for the modelling of the DED configuration of TEXTOR is used. A generalization and extension of this model was necessary to be able to handle W7-X. The model solves the transport equations with Monte Carlo techniques making use of mappings of local magnetic coordinates. The application of this technique to W7-X in a limiter-like configuration is presented. The decreasing dominance of parallel transport with respect to radial transport for electron heat, ion heat and particle transport results in increasingly steep profiles for the respective quantities within the islands.

Published
2004
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17. Low-recycling conditions and improved core confinement in steady-state operation scenarios in JET (Joint European Torus)

Author

R. Zagorski, V. Pericoli, M. Beurskens, Y. Baranov, A. Fonseca, J. Mailloux, S. Saarelma, D. Mc Donald, I. T. Chapman, R. Cesario, M. Zerbini, M. Marinucci, Frank Jenko, D. Told, Alessandro Galli, R. De Angelis, L. Amicucci, Jet-Efda Contributors, C. Challis, P. Smeulders, Zerbini, M., De Angelis, R., Smeulders, P., Marinucci, M., and Cesario, R.

Subjects
Shear (sheet metal), Physics, Jet (fluid), Steady state, Nuclear Energy and Engineering, Joint European Torus, Particle, Electron temperature, Plasma, Mechanics, Atomic physics, Condensed Matter Physics, Bootstrap current
Abstract

In this paper, we discuss the phenomena that link particle recycling from the vessel walls in the L-mode during discharge start-up and the core confinement in the H-mode during the subsequent main heating phase. We consider available data of JET experiments that aimed at approaching fully non-inductive ITER-relevant steady-state conditions and show that the high electron temperature produced at the edge by a low recycling during start-up tends to favour the build-up of high normalized β(βN) regimes in the H-mode, the confinement being improved in a large plasma volume. To provide an insight into this complex phenomenon we have modelled the relation between particle recycling in the scrape-off layer and the evolution of plasma transport, plasma current density and shear as well as the stability properties for such experimental conditions. The results confirm the existence of a link between the confinement in the H-mode phase and the values at the edge of electron temperature, bootstrap current density and local magnetic shear during start-up. Such a link could favour these regimes to be self-sustained in time. © 2013 IOP Publishing Ltd.

Published
2013

18. Modelling of impurity production and transport in the scrape-off layer of a high density limiter tokamak

Author

R. Zagorski and F. Romanelli

Subjects
Nuclear and High Energy Physics, Tokamak, Materials science, Plasma parameters, Plasma, Function (mathematics), Mechanics, Condensed Matter Physics, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), law.invention, Ion, Physics::Plasma Physics, Impurity, law, Limiter, Statistical physics, Test particle
Abstract

A simple analytical model is presented that describes impurity ion production and transport in the tokamak scrap-off layer (SOL). The equations of the model are solved analytically in the test particle approximation. The solution, as a function of different plasma parameters and target materials, is discussed in the case in which the background plasma is described by the simple SOL model and a comparison between the model and the numerical results of a 2-D multifluid code is presented

Published
1996
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19. 'Snow Flakes' Divertor and 10 MA Scenarios in FAST

Author

Crisanti F., Martin P., Mantica P., Calabro G., Fusco V., Pericoli Ridolfini V., Puiatti M. E., Lauro Taroni L., Valisa M., Villone F., Vlad G., and R. Zagorski

Subjects
____
Abstract

___

Published
2012

20. Scenario Development for FAST in the View of ITER and DEMO

Author

F. Crisanti, R. Albanese, F. Artaud, O. Asunta, B. Baiocchi, M. Baruzzo, V. Ba- Siuk, A. Bierwage, R. Bilato, T. Bolzonella, M. Brambilla, G. Breyiannis, S. Briguglio, G. Calabro, A. Cardinali, G. Corrigan, A. Cucchiaro, C. Di Troia, D. Farina, L. Fig- Ini, G. Fogaccia, G. Giruzzi, G. Granucci, F. Imbeaux, T. Johnson, L. Lauro Taroni, G. Maddaluno, R. Maggiora, P. Mantica, M. Marinucci, D. Milanesio, V. Parail, V. Pericoli-Ridolfini, A. Pizzuto, S. Podda, G. Ramogida, A. Salmi, M. Santinelli, M. Schneider, A. Tuccillo, M. Valisa, R. Villari, B. Viola, G. Vlad, X. Wang, R. Zagorski, and F. Zonca

Published
2010

21. Stationary Study of the Boundry Plasma of Large Tokamaks with Divertor

Author

A. Galkowski and R. Zagorski

Subjects
Tokamak, Steady state, Materials science, Divertor, chemistry.chemical_element, Rate equation, Plasma, Condensed Matter Physics, law.invention, Magnetic field, chemistry, Physics::Plasma Physics, law, Impurity, Atomic physics, Helium
Abstract

The hydrogen plasma and impurity flows parallel to the magnetic field lines in a collissional tokamak scrape-off layer are numerically investigated. The physical model is developed on the basis of electron-ion fluid equations for hydrogen plasma and rate equations for impurities. A complex model valid for arbitrary concentration of impurity ions based on 21-moment Grad approximation is used to describe transport coefficients and thermal forces. Plasma interactions with neutral particles recycling at the divertor plate are taken into account. Steady state spatial profiles of the plasma and impurity (0, C) parameters are computed using the time relaxation method Possibility of helium exhaust is investigated.

Published
1990
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23. Global Particle Balance and Local Particle Tarnsport in the Frascati Tokamak Upgrade

Author

F Alladio, M L Apicella, G Apruzzese, E Bartiromo, O Borra, G Bracco, G Buceti, P Buratti, C Centioli, M Ciotti, V Cocilovo, I Condrea, F Crisanti, R DeAngelis, D Frigione, L Gabellieri, E Giovannozzi, G Granucci, M Grolli, A Imparato, H Kroegler, M Leigheb, L Lovisetto, G Maddaluno, G Mazzitelli, P Micozzi, A Moleti, F Orsitto, L Panaccione, D Pacella, M Panella, V Pericoli, L Pieroni, S Podda, G B Righetti, F Romanelli, S E Segre, E Sternini, A A Tuccillo, O Tudisco, F Valente, V Vitale, R Zagorski, V Zanza, and M Zerbini

Subjects
__
Abstract

__

Published
1995

24. TECXY simulations of Ne seeding in JET high power scenarios

Author

P. Chmielewski, R. Zagórski, G. Telesca, M. Brix, A. Huber, I. Ivanova-Stanik, E. Kowalska-Strzeciwilk, T. Pereira, D.I. Réfy, P. Tamain, M. Vécsei, and N. Vianello

Subjects
Nuclear engineering. Atomic power, TK9001-9401
Abstract

Preparation of D-T experiments on JET device raises a question about the mitigation of assumed high power entering the SOL. JET DT scenarios aim to achieve good plasma confinement and the heat loads reduction to the divertor at the same time. Therefore, the divertor corner magnetic field geometry, strike point swiping and impurity seeding are considered to reduce expected high heat fluxes to the divertor plates. The aim of the paper is to analyse the influence of the neon impurity seeding on the plasma transport and its efficiency of the power mitigation in the JET tokamak as well as to perform validation of applied edge plasma model. In this contribution numerical simulations have been performed for two high power (34 MW), neon seeded DD JET discharges in the H-mode with different upstream densities and the same corner divertor configuration prepared as possible candidate for JET DT scenarios. The edge plasma transport have been described by two-dimensional multifluid TECXY code based on Braginskii plasma transport equations with assumed classical parallel transport of the plasma and anomalous perpendicular transport defined by ad hoc heat and particle transport coefficients. TECXY results show impact of the neon seeding on the reduction of the power flowing to the divertor. Scan with the neon concentration carried out for four different upstream densities allow us to determine optimal plasma conditions with the lowest target plate temperature and the lowest effective charge. Performed studies with use of the TECXY code and they comparison to experimental results give the opportunity to perform validation of applied TECXY edge plasma model and show the optimal range of plasma parameters like the upstream density and neon concentration, for which the radiation power in the SOL is the highest.

Published
2021
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25. A Simple Model for Impurity Production in Tokamaks

Author

F. Romanelli, R. Zagorski, and Romanelli, F.

Subjects
Physics, Tokamak, Plasma parameters, Plasma, Condensed Matter Physics, Computational physics, law.invention, Physics::Plasma Physics, Simple (abstract algebra), Impurity, law, Limiter, Atomic physics, Test particle, Impurity ions
Abstract

A simple analytical model is presented for the plasma in the region outside the limiter which describes the impurity ions transport and production in the tokamak scrape‐off layer. The equations of the model are solved analytically in the test particle approximation for the simple SOL configurations. A discussion of the solutions for different plasma parameters and target materials is presented. Copyright © 1994 WILEY‐VCH Verlag GmbH & Co. KGaA

Published
1994

26. Integrated scenario with type-III ELMy H-mode edge: extrapolation to ITER

Author

T. Eich, R. Zagorski, P. Monier-Garbet, G.J. van Rooij, Olivier Sauter, A. Korotkov, P. de Vries, Y. Andrew, W. Fundamenski, Juergen Rapp, P. D. Morgan, D. Howell, Stéphane Devaux, G. Telesca, A. G. Meigs, E. Joffrin, M. Beurskens, D. C. McDonald, A. Huber, M. F. Stamp, Jet-Efda Contributors, S. Jachmich, Y. Corre, C. Giroud, G. F. Matthews, M. R. de Baar, R. Felton, I. Nunes, M. Brix, and S. Brezinsek

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, Gyroradius, Nuclear engineering, Divertor, Magnetic confinement fusion, Fusion power, Collisionality, Condensed Matter Physics, law.invention, Nuclear physics, ASDEX Upgrade, Physics::Plasma Physics, law, Beta (plasma physics)
Abstract

One of the most severe problems for fusion reactors is the power load on the plasma facing components. The challenge is to develop operation scenarios, which combine sufficient energy confinement with benign heat loads to the plasma facing components. The radiative type-III ELMy H-mode seems a possible solution for such an integrated ITER scenario. Nitrogen seeded type-III ELMy H-modes for the standard inductive scenario and the high beta stationary hybrid scenario are investigated with respect to their transient and steady-state power fluxes to the divertor, confinement properties, edge operational space, core operational space, plasma purity and MHD behaviour. A large database of highly radiative type-III ELMy H-modes on JET is used for extrapolations to ITER. On this basis the transient heat load should be acceptable for ITER. It was found that the scaling of the confinement time with respect to the ion gyroradius is close to the gyro-Bohm scaling. Scalings with respect to the plasma collisionality suggest that the confinement will be good enough for an ITER scenario at 17 MA with a power amplification factor (Q) of 10 and might be marginally good enough for a Q = 10 scenario at 15 MA. Those extrapolations are supported by simulations with an integrated core/edge model COREDIV. In addition the hybrid scenario with type-III edge localized modes has been proven to have improved edge conditions without any modification of the central plasma current profile, indicating it is compatible with a high beta operation for a steady-state ITER Q = 5 scenario.

Published
2009
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27. Topoisomerase II activity in the replicating DNA of irradiated hamster cells

Author

R L, Warters and R, Zagorski

Subjects
DNA Replication, DNA Topoisomerases, Type II, Cricetinae, Animals, CHO Cells, DNA, DNA Damage
Abstract

The activity of DNA topoisomerase II in the replicating DNA of irradiated Chinese hamster ovary cells was estimated by determining protein-linked DNA double-strand breaks generated in the presence of the DNA intercalative drug 4'-(9-acridinylamino) methanesulfon-m-anisidide. In the presence of this drug, DNA double-strand breaks were produced at the same rate, and with the same overall frequency, in both the bulk and the newly synthesized DNA of control cells and cells irradiated with 10 Gy. The results indicate that DNA topoisomerase II is fully active in the replicating DNA of irradiated cells and is distributed at a frequency similar to that in parental DNA.

Published
1991

28. Numerical investigations of edge plasma flows in the Tore Supra tokamak.

Author

R Zagorski, J P Gunn, and I Nanobashvili

Subjects
*PLASMA gases, *NUMERICAL analysis, *TOKAMAKS, *BOUNDARY layer (Aerodynamics), *EXPERIMENTS, *ELECTRIC fields
Abstract

The 2D boundary layer code TECXY has been used to simulate edge plasma parameters in the Tore Supra tokamak. Experimental situations have been analysed when the plasma contact point is shifted to different poloidal positions (limiter at bottom, top, outboard and inboard midplane) as well as the edge plasma conditions during lower hybrid RF power scan experiments. With the results of the calculations it was possible to reproduce experimentally observed changes to the flow pattern in the scrape-off-layer (SOL) for different plasma positions. These changes can be associated with the dependence of the radial electric field and the corresponding E x B drift velocity on the limiter position as well as to the poloidal asymmetries of the input particle flux. However, the code results with 'standard radial transport' did not show the large changes to the SOL widths as observed in the experiment. In order to reproduce in the calculations the observed differences in the SOL width, it was necessary to assume strong convective (or diffusive) radial plasma flow localized at the outboard midplane. [ABSTRACT FROM AUTHOR]

Published
2007

29. Edge properties with the liquid lithium limiter in FTU-experiment and transport modelling.

Author

V Pericoli, M L Apicella, G Mazzitelli, O Tudisco, R Zagorski, and the FTU

Subjects
LITHIUM, LIQUID metals, PLASMA gases, ELECTRIC discharges, ELECTRON temperature, FLUID dynamics, EXPERIMENTS, TRANSPORT theory
Abstract

Liquid lithium as a plasma-facing material was tested for the first time on a high field medium size tokamak, FTU. A liquid Li reservoir supplies a mesh of capillaries that is movable from shot to shot in the scrape-off layer (SOL) plasma to act as a secondary limiter. An almost complete lithization of the vacuum vessel walls is obtained in about three discharges. Plasmas cleaner than boronization and titanization, with lower radiation losses and smaller impurity content are produced. The SOL electron temperature increases, DTe [?] 10 eV, while density (ne) is less affected. The 2D multifluid code TECXY explains this only if a strong reduction of plasma recycling on the walls and main limiter occurs, consistent with the high Li hydrogen pumping capability. This property also permits a much tighter control of the plasma density. With the Li limiter inserted inside the vessel poloidal asymmetries develop in the SOL that TECXY explains with a local increase of radiation, caused by enhanced evaporation/sputtering of Li. New regimes can be produced in such conditions with a clear increase in |[?]ne/ne| and of the peaking factor ne0/

Published
2007
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30. High power neon seeded JET discharges: Experiments and simulations

Author

G. Telesca, I. Ivanova-Stanik, R. Zagórski, S. Brezinsek, A. Czarnecka, P. Drewelow, C. Giroud, A. Huber, S. Wiesen, and M. Wischmeier

Subjects
Nuclear engineering. Atomic power, TK9001-9401
Abstract

A series of neon seeded JET ELMy H-mode pulses is considered from the modeling as well as from the experimental point of view. For two different Ne seeding rates and two different D puffing gas levels the heating power, Pheat, is in the range 22–29.5 MW. The main focus is on the numerical reconstruction of the total radiated power (which mostly depends on the W concentration) and its distribution between core and divertor and of Zeff (which mostly depends on the Ne concentration). To model self-consistently the core and the SOL two input parameters had to be adjusted case by case: the SOL diffusivity, DSOL, and the core impurity inward pinch, vpinch. DSOL had to be increased with increasing ΓNe and the level of vpinch had to be changed, for any given ΓNe, according to the level of Pheat: it decreases with increasing Pheat. Since the ELM frequency, fELM, is experimentally correlated with Pheat, (it increases with Pheat) the impurity inward pinch can be seen as to depend on fELM. Therefore, to maintain a low vpinch level (i.e. high fELM) ΓNe/Pheat should not exceed a certain threshold, which slightly increases with the ΓD puffing rate. This might lead to a limitation in the viability of reducing the target heat load by Ne seeding at moderate ΓD, while keeping Zeff at acceptably low level. Keywords: Tokamak, Integrated modeling, Core plasma, Edge plasma

Published
2017
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31. Modeling of solidification of MMC composites during gravity casting process

Author

R. Zagórski and S. Golak

Subjects
casting solidification, aluminum matrix composites, simulation, computational fluid dynamic (CFD), Mining engineering. Metallurgy, TN1-997
Abstract

The paper deals with computer simulation of gravity casting of the metal matrix composites reinforced with ceramics (MMC) into sand mold. The subject of our interest is aluminum matrix composite (AlMMC) reinforced with ceramic particles i.e. silicon carbide SiC and glass carbon Cg. The created model describes the process taking into account solidification and its influence on the distribution of reinforcement particles. The computer calculation has been carried out in 2D system with the use of Navier-Stokes equations using ANSYS FLUENT 13. The Volume of Fluid approach (VOF) and enthalpy method have been used to model the air-fluid free surface (and also volume fraction of particular continuous phases) and the solidification of the cast, respectively.

Published
2013

32. Simulation with the COREDIV code of nitrogen-seeded H-mode discharges at JET.

Author

G Telesca, R Zagorski, S Brezinsek, W Fundamenski, C Giroud, G Maddison, M O' Mullane, J Rapp, M Stamp, G Van, Oost and, and JET EFDA

Subjects
*SIMULATION methods & models, *COMPUTER software, *NITROGEN, *ELECTRIC discharges, *SELF-consistent field theory, *PLASMA gases, *NUMERICAL analysis, *IMPURITY centers
Abstract

The code COREDIV, self-consistent with respect to both the interaction of plasma core-edge and main plasma impurities, is used to simulate nitrogen-seeded discharges in JET. The model is fully described and numerical results are compared with experimental data pertaining to two series of discharges differing in input power, confinement, the level of power radiated and the puffing rate of the main gas. Impurity sources, their transport and densities are considered as functions of the edge and core parameters and consistency of their radiated power is discussed. Special emphasis is given to analysis of the fluxes of carbon and recycled deuterium. [ABSTRACT FROM AUTHOR]

Published
2011

33. Edge transport in fusion plasmas.

Author

V Naulin, W Fundamenski, and R Zagorski

Subjects
PLASMA gases, NUCLEAR fusion, MAGNETIC fields, TURBULENCE, FLUID dynamics, INTERFACES (Physical sciences), SIMULATION methods & models
Abstract

It has long been recognized that the plasma edge and the interaction of the plasma with material interfaces through the scrape-off layer (SOL) is crucial for the successful operation of future fusion machines, e.g. ITER. Tremendous progress has been achieved in the last decade in diagnosing, modelling and understanding this plasma region. Nonetheless, many important questions remain unanswered, e.g. the origin of parallel SOL flows, of ELM types or even of the L-H transition itself. While scientists often specialize and work either on the confined edge region or on the open magnetic field line region (SOL) it is obvious that the unsolved problems in the field can only be addressed by treating the pedestal and SOL regions in an integrated manner, thereby capturing their dynamical interaction. The present cluster issue is intended to provide an actual overview of the field of plasma edge and scrape-off layer both from the simulation/theory and the experimental side. The papers originate from contributions made to the IEA Large Tokamak IA Workshop on `Edge Transport in Fusion Plasmas'' which was held in Krakow, Poland, 11-13 September 2006, in the cultural centre `Dom Polonii'' (http://www.etfp2006.ifpilm.waw.pl). The workshop was attended by 30 participants from all over the world, many of whom are leading experts in their respective areas of work. The presentations focused on both experimental and theoretical aspects, from edge turbulence, edge localized modes (ELMs), to challenges in edge modelling using fluid and kinetic codes. It was a goal of the meeting, which was held in a convivial atmosphere of scientific debate, to bring together the progress made in diagnostics with the current state of the art in theory and code development. The nine papers in this cluster issue will provide an actual snapshot of this exciting and quickly evolving field. They cover a large number of themes, from edge turbulence measurements (Zweben) and simulation (Scott), via experimental (Kamiya) and numerical (Pankin) investigations of ELMs, towards developments of integrated transport codes (Kawashima) and a discussion of challenges facing edge modelling in the future (Schneider). The contributions also deal with topical themes of SOL flows (Zagorski), magnetic field ergodization (Jakubowski) and liquid lithium limiters (Pericoli). It is hoped that they provide compact access and a point of reference for the rapidly progressing work towards scientific understanding and finally control of the plasma edge and SOL region. [ABSTRACT FROM AUTHOR]

Published
2007
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34. Staphylococcal saoABC Operon Codes for a DNA-Binding Protein SaoC Implicated in the Response to Nutrient Deficit.

Author

Bukowski M, Kosecka-Strojek M, Madry A, Zagorski-Przybylo R, Zadlo T, Gawron K, and Wladyka B

Subjects
Amino Acids metabolism, Bacterial Proteins genetics, Bacterial Proteins metabolism, DNA-Binding Proteins metabolism, Gene Expression Regulation, Bacterial, Humans, Nutrients, Operon genetics, Staphylococcus genetics, Virulence Factors metabolism, Staphylococcal Infections microbiology, Staphylococcus aureus metabolism
Abstract

Whilst a large number of regulatory mechanisms for gene expression have been characterised to date, transcription regulation in bacteria still remains an open subject. In clinically relevant and opportunistic pathogens, such as Staphylococcus aureus, transcription regulation is of great importance for host-pathogen interactions. In our study we investigated an operon, exclusive to staphylococci, that we name saoABC. We showed that SaoC binds to a conserved sequence motif present upstream of the saoC gene, which likely provides a negative feedback loop. We have also demonstrated that S. aureus ΔsaoB and ΔsaoC mutants display altered growth dynamics in non-optimal media; ΔsaoC exhibits decreased intracellular survival in human dermal fibroblasts, whereas ΔsaoB produces an elevated number of persisters, which is also elicited by inducible production of SaoC in ΔsaoBΔsaoC double mutant. Moreover, we have observed changes in the expression of saoABC operon genes during either depletion of the preferential carbon or the amino acid source as well as during acidification. Comparative RNA-Seq of the wild type and ΔsaoC mutant demonstrated that SaoC influences transcription of genes involved in amino acid transport and metabolism, and notably of those coding for virulence factors. Our results suggest compellingly that saoABC operon codes for a DNA-binding protein SaoC, a novel staphylococcal transcription factor, and its antagonist SaoB. We linked SaoC to the response to nutrient deficiency, a stress that has a great impact on host-pathogen interactions. That impact manifests in SaoC influence on persister formation and survival during internalisation to host cells, as well as on the expression of genes of virulence factors that may potentially result in profound alternations in the pathogenic phenotype. Investigation of such novel regulatory mechanisms is crucial for our understanding of the dynamics of interactions between pathogenic bacteria and host cells, particularly in the case of clinically relevant, opportunistic pathogens such as Staphylococcus aureus.

Published
2022
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35. Prevalence of Antibiotic and Heavy Metal Resistance Determinants and Virulence-Related Genetic Elements in Plasmids of Staphylococcus aureus .

Author

Bukowski M, Piwowarczyk R, Madry A, Zagorski-Przybylo R, Hydzik M, and Wladyka B

Abstract

The use of antibiotics on a mass scale, particularly in farming, and their release into the environment has led to a rapid emergence of resistant bacteria. Once emerged, resistance determinants are spread by horizontal gene transfer among strains of the same as well as disparate bacterial species. Their accumulation in free-living as well as livestock and community-associated strains results in the widespread multiple-drug resistance among clinically relevant species posing an increasingly pressing problem in healthcare. One of these clinically relevant species is Staphylococcus aureus , a common cause of hospital and community outbreaks. Among the rich diversity of mobile genetic elements regularly occurring in S. aureus such as phages, pathogenicity islands, and staphylococcal cassette chromosomes, plasmids are the major mean for dissemination of resistance determinants and virulence factors. Unfortunately, a vast number of whole-genome sequencing projects does not aim for complete sequence determination, which results in a disproportionately low number of known complete plasmid sequences. To address this problem we determined complete plasmid sequences derived from 18 poultry S. aureus strains and analyzed the prevalence of antibiotic and heavy metal resistance determinants, genes of virulence factors, as well as genetic elements relevant for their maintenance. Some of the plasmids have been reported before and are being found in clinical isolates of strains typical for humans or human ones of livestock origin. This shows that livestock-associated staphylococci are a significant reservoir of resistance determinants and virulence factors. Nevertheless, nearly half of the plasmids were unknown to date. In this group we found a potentially mobilizable plasmid pPA3 being a unique example of accumulation of resistance determinants and virulence factors likely stabilized by a presence of a toxin-antitoxin system.

Published
2019
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36. Topoisomerase II activity in the replicating DNA of irradiated hamster cells.

Author

Warters RL and Zagorski R

Subjects
Animals, CHO Cells radiation effects, Cricetinae, DNA analysis, DNA Damage, DNA Topoisomerases, Type II analysis, DNA Replication, DNA Topoisomerases, Type II radiation effects
Abstract

The activity of DNA topoisomerase II in the replicating DNA of irradiated Chinese hamster ovary cells was estimated by determining protein-linked DNA double-strand breaks generated in the presence of the DNA intercalative drug 4'-(9-acridinylamino) methanesulfon-m-anisidide. In the presence of this drug, DNA double-strand breaks were produced at the same rate, and with the same overall frequency, in both the bulk and the newly synthesized DNA of control cells and cells irradiated with 10 Gy. The results indicate that DNA topoisomerase II is fully active in the replicating DNA of irradiated cells and is distributed at a frequency similar to that in parental DNA.

Published
1991

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