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31 results on '"Matteo Agostini"'

1. Statistical methods in sterile neutrino experiments

Author

Birgit Neumair and Matteo Agostini

Subjects
Physics, History, Sterile neutrino, Particle physics, Computer Science Applications, Education, ddc
Abstract

We compare the current statistical methods applied to short-baseline neutrino oscillation experiments looking for light sterile neutrinos. The interpretation of the reconstructed confidence regions differs because of the different definition of the alternative hypothesis in the hypothesis test. When the alternative hypothesis extends over the whole physical allowed parameter space of the oscillation parameters, proper confidence regions are obtained both in case of a limit and a signal. Since the different definition of the alternative hypothesis prevents from a direct comparison of the results, a standardized analysis is proposed.

Published
2019

2. Physics research on the TCV tokamak facility: From conventional to alternative scenarios and beyond

Author

G. Tomaž, M. Weiland, J. Gath, Antti Hakola, Kevin Verhaegh, A.J. Thornton, Matthew Carr, J. Juul Rasmussen, S. Costea, Jorge Morales, A. Perek, X. Feng, F. Pesamosca, Marcelo Baquero-Ruiz, N. Vianello, A. Dal Molin, N. M. T. Vu, D. Hogeweij, G. Calabrò, Tom Wauters, Christian Hopf, E. Alessi, Aitor J. Garrido, Justin Ball, Daniele Carnevale, A. Czarnecka, S. Garavaglia, G. Ferro, George Wilkie, N. Krawczyk, M. Nocente, H. De Oliveira, Ivo Furno, W. Bin, O. Chellai, Stefano Coda, Fulvio Auriemma, Yann Camenen, W. A. J. Vijvers, Christian Theiler, A. N. Karpushov, M. Faitsch, Jérôme Bucalossi, Paolo Ricci, Antoine Merle, T. C. Blanken, Cristian Galperti, Duccio Testa, Ambrogio Fasoli, Y. Andrebe, F. Bagnato, S. Nowak, J. R. Harrison, O. Vasilovici, M. E. Puiatti, Stefan Kragh Nielsen, J. S. Allcock, L. Calacci, Matteo Zuin, V. Piergotti, P. Chmielewski, P. Molina Cabrera, Taina Kurki-Suonio, D. Micheletti, Emanuele Poli, Nuno Cruz, M. Farnik, Jonathan Graves, Alessandro Pau, Olivier Février, N. A. Kirneva, Bruce Lipschultz, E. Lazzaro, E. Havlickova, G. Giruzzi, Jens Madsen, L. Stipani, D. Brida, Ch. Schlatter, M. Wensing, R. O. Pavlichenko, F. Nespoli, J. Decker, Eva Macusova, Fulvio Militello, Nicola Offeddu, Heinz Isliker, A. Zisis, A. Marco, Laurie Porte, Marco Gobbin, Anna Salmi, S. Vartanian, J. Sinha, Matthias Komm, M. Spolaore, Anders Nielsen, T. Happel, R. D. Nem, A. Iantchenko, V.V. Plyusnin, C. Tsironis, V. Igochine, R. M. McDermott, Pär Strand, Benjamin Daniel Dudson, T. Ravensbergen, V. P. Loschiavo, H. Arnichand, E. Viezzer, Fabio Villone, Carlo Sozzi, Z. Huang, V. Pericoli Ridolfini, B. Linehan, L. Hesslow, P. Buratti, A. Casolari, M. Bernert, P. Mantica, H. Weisen, J-M Moret, Maiko Yoshida, N. Bonanomi, S. Feng, A. A. Teplukhina, Jakub Urban, F. Carpanese, C. Piron, S. Allan, Minh Quang Tran, C. Marini, Artur Palha, F.P. Orsitto, Roberto Ambrosino, A. S. Tema Biwole, Harry M. Meyer, Davide Galassi, J. Mlynář, N. Christen, M. Wischmeier, Mathias Hoppe, P. David, J. Horacek, M. Maraschek, G. Ciraolo, R. R. Sheeba, J. Zebrowski, M. Dreval, M. Silva, K. Gałązka, Olivier Sauter, Laure Vermare, A. Gallo, C. Reux, M. Gospodarczyk, O. Bogar, Roman Schrittwieser, C. Marchetto, Patrick J. McCarthy, Joël Rosato, G. Pucella, K. Wu, Volker Naulin, Bojan Mavkov, S. Elmore, Lorella Carraro, Gustavo Granucci, Christopher N. Bowman, O. Kudlacek, M. Gruca, A. Jardin, Federico Felici, Didier Mazon, D. C. van Vugt, D. Douai, Jose Boedo, Raffaele Albanese, U. A. Sheikh, Hugo Bufferand, R. Lombroni, T. Pütterich, Benedikt Geiger, X. Llobet, Izaskun Garrido, J.-Ph. Hogge, J. Ayllon-Guerola, Nicolas Fedorczak, Timothy Goodman, A. Mariani, E. Maljaars, Matteo Agostini, Lorenzo Frassinetti, S. E. Sharapov, C.K. Tsui, Vladimir E. Moiseenko, Robert Mumgaard, Amanda Hubbard, L. Pigatto, F. Matos, D. S. Gahle, Roberto Maurizio, I. Voitsekhovitch, Paolo Zanca, J. Buermans, A. Fil, T. Lunt, S. S. Henderson, D. Ricci, M. Kong, Ondrej Ficker, Matthias Wiesenberger, L. Cordaro, P. Innocente, Roberto Paccagnella, Benoit Labit, N. Rispoli, M. Rabinski, G. F. Harrer, Roch Kwiatkowski, A. Moro, A. A. Beletskii, M. Vallar, M. Reich, F. Reimold, P. Piovesan, Mirko Salewski, J. Hawke, Giuseppe Gorini, J. Čeřovský, F. Causa, H. Reimerdes, B. Esposito, Jernej Kovacic, P. V. Kazantzidis, H. Anand, Gergely Papp, M. Valisa, K. Mitosinkova, Vlado Menkovski, F. Bombarda, M. Fontana, Tommaso Bolzonella, Pascale Hennequin, T. Gyergyek, D. L. Keeling, T. Eich, M. Garcia-Munoz, Stefano Alberti, P. Blanchard, F. Bouquey, R. Shousha, M. Scheffer, B. S. Schneider, R. Jacquier, D. Choi, Nick Walkden, Ola Embréus, C. Ionita Schrittwieser, S. Saarelma, J. Garcia, M. G. Dunne, M. Tomes, R. Zagórski, Y. R. Martin, A. Kappatou, B. P. Duval, T. Tala, Swiss National Science Foundation, Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Institut de Recherche sur la Fusion par confinement Magnétique (IRFM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Istituto di Fisica del Plasma, EURATOM-ENEA-CNR Association, Consiglio Nazionale delle Ricerche [Roma] (CNR), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de Recherches en Physique des Plasmas (CRPP), Department of Physics [Stockholm], Stockholm University, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), EURATOM/CCFE Fusion Association, Culham Science Centre [Abingdon], York Plasma Institute (YPI), University of York [York, UK], Faculty of Mathematics and Physics [Praha/Prague], Charles University [Prague] (CU), Association EURATOM-CEA (CEA/DSM/DRFC), University College Cork (UCC), Department of Mechanical and Manufacturing Engineering [Aalborg] (M-TECH), Aalborg University [Denmark] (AAU), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), Instituto de Plasmas e Fusão Nuclear [Lisboa] (IPFN), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Coda, S, Agostini, M, Albanese, R, Alberti, S, Alessi, E, Allan, S, Allcock, J, Ambrosino, R, Anand, H, Andrebe, Y, Arnichand, H, Auriemma, F, Ayllon-Guerola, J, Bagnato, F, Ball, J, Baquero-Ruiz, M, Beletskii, A, Bernert, M, Bin, W, Blanchard, P, Blanken, T, Boedo, J, Bogar, O, Bolzonella, T, Bombarda, F, Bonanomi, N, Bouquey, F, Bowman, C, Brida, D, Bucalossi, J, Buermans, J, Bufferand, H, Buratti, P, Calabro, G, Calacci, L, Camenen, Y, Carnevale, D, Carpanese, F, Carr, M, Carraro, L, Casolari, A, Causa, F, Cerovsky, J, Chellai, O, Chmielewski, P, Choi, D, Christen, N, Ciraolo, G, Cordaro, L, Costea, S, Cruz, N, Czarnecka, A, Dal Molin, A, David, P, Decker, J, De Oliveira, H, Douai, D, Dreval, M, Dudson, B, Dunne, M, Duval, B, Eich, T, Elmore, S, Embreus, O, Esposito, B, Faitsch, M, Farnik, M, Fasoli, A, Fedorczak, N, Felici, F, Feng, S, Feng, X, Ferro, G, Fevrier, O, Ficker, O, Fil, A, Fontana, M, Frassinetti, L, Furno, I, Gahle, D, Galassi, D, Galazka, K, Gallo, A, Galperti, C, Garavaglia, S, Garcia, J, Garcia-Munoz, M, Garrido, A, Garrido, I, Gath, J, Geiger, B, Giruzzi, G, Gobbin, M, Goodman, T, Gorini, G, Gospodarczyk, M, Granucci, G, Graves, J, Gruca, M, Gyergyek, T, Hakola, A, Happel, T, Harrer, G, Harrison, J, Havlickova, E, Hawke, J, Henderson, S, Hennequin, P, Hesslow, L, Hogeweij, D, Hogge, J, Hopf, C, Hoppe, M, Horacek, J, Huang, Z, Hubbard, A, Iantchenko, A, Igochine, V, Innocente, P, Ionita Schrittwieser, C, Isliker, H, Jacquier, R, Jardin, A, Kappatou, A, Karpushov, A, Kazantzidis, P, Keeling, D, Kirneva, N, Komm, M, Kong, M, Kovacic, J, Krawczyk, N, Kudlacek, O, Kurki-Suonio, T, Kwiatkowski, R, Labit, B, Lazzaro, E, Linehan, B, Lipschultz, B, Llobet, X, Lombroni, R, Loschiavo, V, Lunt, T, Macusova, E, Madsen, J, Maljaars, E, Mantica, P, Maraschek, M, Marchetto, C, Marco, A, Mariani, A, Marini, C, Martin, Y, Matos, F, Frisina, M, Mavkov, B, Mazon, D, Mccarthy, P, Mcdermott, R, Menkovski, V, Merle, A, Meyer, H, Micheletti, D, Militello, F, Mitosinkova, K, Mlynar, J, Moiseenko, V, Molina Cabrera, P, Morales, J, Moret, J, Moro, A, Mumgaard, R, Naulin, V, Nem, R, Nespoli, F, Nielsen, A, Nielsen, S, Nocente, M, Nowak, S, Offeddu, N, Orsitto, F, Paccagnella, R, Palha, A, Papp, G, Pau, A, Pavlichenko, R, Perek, A, Pericoli Ridolfini, V, Pesamosca, F, Piergotti, V, Pigatto, L, Piovesan, P, Piron, C, Plyusnin, V, Poli, E, Porte, L, Pucella, G, Puiatti, M, Putterich, T, Rabinski, M, Juul Rasmussen, J, Ravensbergen, T, Reich, M, Reimerdes, H, Reimold, F, Reux, C, Ricci, D, Ricci, P, Rispoli, N, Rosato, J, Saarelma, S, Salewski, M, Salmi, A, Sauter, O, Scheffer, M, Schlatter, C, Schneider, B, Schrittwieser, R, Sharapov, S, Sheeba, R, Sheikh, U, Shousha, R, Silva, M, Sinha, J, Sozzi, C, Spolaore, M, Stipani, L, Strand, P, Tala, T, Tema Biwole, A, Teplukhina, A, Testa, D, Theiler, C, Thornton, A, Tomaz, G, Tomes, M, Tran, M, Tsironis, C, Tsui, C, Urban, J, Valisa, M, Vallar, M, Van Vugt, D, Vartanian, S, Vasilovici, O, Verhaegh, K, Vermare, L, Vianello, N, Viezzer, E, Vijvers, W, Villone, F, Voitsekhovitch, I, Vu, N, Walkden, N, Wauters, T, Weiland, M, Weisen, H, Wensing, M, Wiesenberger, M, Wilkie, G, Wischmeier, M, Wu, K, Yoshida, M, Zagorski, R, Zanca, P, Zebrowski, J, Zisis, A, Zuin, M, Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, Coda, S., Agostini, M., Albanese, R., Alberti, S., Alessi, E., Allan, S., Allcock, J., Ambrosino, R., Anand, H., Andrebe, Y., Arnichand, H., Auriemma, F., Ayllon-Guerola, J. M., Bagnato, F., Ball, J., Baquero-Ruiz, M., Beletskii, A. A., Bernert, M., Bin, W., Blanchard, P., Blanken, T. C., Boedo, J. A., Bogar, O., Bolzonella, T., Bombarda, F., Bonanomi, N., Bouquey, F., Bowman, C., Brida, D., Bucalossi, J., Buermans, J., Bufferand, H., Buratti, P., Calabro, G., Calacci, L., Camenen, Y., Carnevale, D., Carpanese, F., Carr, M., Carraro, L., Casolari, A., Causa, F., Cerovsky, J., Chellai, O., Chmielewski, P., Choi, D., Christen, N., Ciraolo, G., Cordaro, L., Costea, S., Cruz, N., Czarnecka, A., Dal Molin, A., David, P., Decker, J., De Oliveira, H., Douai, D., Dreval, M. B., Dudson, B., Dunne, M., Duval, B. P., Eich, T., Elmore, S., Embreus, O., Esposito, B., Faitsch, M., Farnik, M., Fasoli, A., Fedorczak, N., Felici, F., Feng, S., Feng, X., Ferro, G., Fevrier, O., Ficker, O., Fil, A., Fontana, M., Frassinetti, L., Furno, I., Gahle, D. S., Galassi, D., Galazka, K., Gallo, A., Galperti, C., Garavaglia, S., Garcia, J., Garcia-Munoz, M., Garrido, A. J., Garrido, I., Gath, J., Geiger, B., Giruzzi, G., Gobbin, M., Goodman, T. P., Gorini, G., Gospodarczyk, M., Granucci, G., Graves, J. P., Gruca, M., Gyergyek, T., Hakola, A., Happel, T., Harrer, G. F., Harrison, J., Havlickova, E., Hawke, J., Henderson, S., Hennequin, P., Hesslow, L., Hogeweij, D., Hogge, J. -P., Hopf, C., Hoppe, M., Horacek, J., Huang, Z., Hubbard, A., Iantchenko, A., Igochine, V., Innocente, P., Ionita Schrittwieser, C., Isliker, H., Jacquier, R., Jardin, A., Kappatou, A., Karpushov, A., Kazantzidis, P. -V., Keeling, D., Kirneva, N., Komm, M., Kong, M., Kovacic, J., Krawczyk, N., Kudlacek, O., Kurki-Suonio, T., Kwiatkowski, R., Labit, B., Lazzaro, E., Linehan, B., Lipschultz, B., Llobet, X., Lombroni, R., Loschiavo, V. P., Lunt, T., Macusova, E., Madsen, J., Maljaars, E., Mantica, P., Maraschek, M., Marchetto, C., Marco, A., Mariani, A., Marini, C., Martin, Y., Matos, F., Maurizio, R., Mavkov, B., Mazon, D., Mccarthy, P., Mcdermott, R., Menkovski, V., Merle, A., Meyer, H., Micheletti, D., Militello, F., Mitosinkova, K., Mlynar, J., Moiseenko, V., Molina Cabrera, P. A., Morales, J., Moret, J. -M., Moro, A., Mumgaard, R. T., Naulin, V., Nem, R. D., Nespoli, F., Nielsen, A. H., Nielsen, S. K., Nocente, M., Nowak, S., Offeddu, N., Orsitto, F. P., Paccagnella, R., Palha, A., Papp, G., Pau, A., Pavlichenko, R. O., Perek, A., Pericoli Ridolfini, V., Pesamosca, F., Piergotti, V., Pigatto, L., Piovesan, P., Piron, C., Plyusnin, V., Poli, E., Porte, L., Pucella, G., Puiatti, M. E., Putterich, T., Rabinski, M., Juul Rasmussen, J., Ravensbergen, T., Reich, M., Reimerdes, H., Reimold, F., Reux, C., Ricci, D., Ricci, P., Rispoli, N., Rosato, J., Saarelma, S., Salewski, M., Salmi, A., Sauter, O., Scheffer, M., Schlatter, C., Schneider, B. S., Schrittwieser, R., Sharapov, S., Sheeba, R. R., Sheikh, U., Shousha, R., Silva, M., Sinha, J., Sozzi, C., Spolaore, M., Stipani, L., Strand, P., Tala, T., Tema Biwole, A. S., Teplukhina, A. A., Testa, D., Theiler, C., Thornton, A., Tomaz, G., Tomes, M., Tran, M. Q., Tsironis, C., Tsui, C. K., Urban, J., Valisa, M., Vallar, M., Van Vugt, D., Vartanian, S., Vasilovici, O., Verhaegh, K., Vermare, L., Vianello, N., Viezzer, E., Vijvers, W. A. J., Villone, F., Voitsekhovitch, I., Vu, N. M. T., Walkden, N., Wauters, T., Weiland, M., Weisen, H., Wensing, M., Wiesenberger, M., Wilkie, G., Wischmeier, M., Wu, K., Yoshida, M., Zagorski, R., Zanca, P., Zebrowski, J., Zisis, A., Zuin, M., Coda, S. et al, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear., Universidad de Sevilla, Departamento de Ingeniería Mecánica y Fabricación, Universidad de Sevilla. TEP111: Ingeniería Mecánica, Universidad de Sevilla. RNM138: Física Nuclear Aplicada, EUROfusion MST1 Team, Control Systems Technology, Data Mining, Science and Technology of Nuclear Fusion, and Magneto-Hydro-Dynamic Stability of Fusion Plasmas

Subjects
Nuclear and High Energy Physics, Tokamak, Settore ING-INF/04, TK, UPGRADE, Cyclotron, Overview, Cyclotron resonance, overview, CONFINEMENT, DETACHMENT, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, law.invention, law, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], CONTROL-SYSTEM, 0103 physical sciences, EUROfusion, 010306 general physics, tokamak, QC, plasma, nuclear fusion, Physics, PLASMA, Divertor, Magnetic confinement fusion, Plasma, Mechanics, TCV, MST1, Condensed Matter Physics, Neutral beam injection, Physics and Astronomy, 13. Climate action, confinement, detachment, Nuclear fusion, control-system, upgrade, TCV, MST1, Beam (structure), Tokamaks
Abstract

The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device's unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly non-inductive H-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power 'starvation' reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached L-mode phase, increasing the outer connection length reduces the in-out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added., This work was supported in part by the Swiss National Science Foundation.

Published
2019

3. Atomistic simulations of gold surface functionalization for nanoscale biosensors applications

Author

Mariacristina Gagliardi, Matteo Agostini, Marco Cecchini, Stefano Corni, Giorgia Brancolini, Luca Bellucci, and Sutapa Dutta

Subjects
Streptavidin, Analyte, Materials science, Bioengineering, 02 engineering and technology, Conjugated system, 010402 general chemistry, 01 natural sciences, nanoscale biosensor, surface functionalization, molecular dynamics, chemistry.chemical_compound, Atomistic simulation, PEG ratio, General Materials Science, Electrical and Electronic Engineering, Mechanical Engineering, technology, industry, and agriculture, General Chemistry, gold surface functionalization, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemical engineering, chemistry, Mechanics of Materials, Biotinylation, Surface modification, 0210 nano-technology, Biosensor, Linker
Abstract

A wide class of biosensors can be built via functionalization of gold surface with proper bio conjugation element capable of interacting with the analyte in solution, and the detection can be performed either optically, mechanically or electrically. Any change in physico-chemical environment or any slight variation in mass localization near the surface of the sensor can cause differences in nature of the transduction mechanism. The optimization of such sensors may require multiple experiments to determine suitable experimental conditions for the immobilization and detection of the analyte. Here, we employ molecular modeling techniques to assist the optimization of a gold-surface biosensor. The gold surface of a quartz-crystal-microbalance sensor is functionalized using polymeric chains of poly(ethylene glycol) (PEG) of 2 KDa molecular weight, which is an inert long chain amphiphilic molecule, supporting biotin molecules (bPEG) as the ligand molecules for streptavidin analyte. The PEG linkers are immobilized onto the gold surface through sulphur chemistry. Four gold surfaces with different PEG linker density and different biotinylation ratio between bPEG and PEG, are investigated by means of state-of-the art atomistic simulations and compared with available experimental data. Results suggest that the amount of biotin molecules accessible for the binding with the protein increases upon increasing the linkers density. At the high density a 1:1 ratio of bPEG/PEG can further improve the accessibility of the biotin ligand due to a strong repulsion between linker chains and different degree of hydrophobicity between bPEG and PEG linkers. The study provides a computaional protocol to model sensors at the level of single molecular interactions, and for optimizing the physical properties of surface conjugated ligand which is crucial to enhance output of the sensor.

Published
2020

4. Searching for neutrinoless double beta decay with GERDA

Author

S. Hemmer, V. N. Kornoukhov, Matthias Laubenstein, K. Pelczar, V. G. Egorov, K. T. Knöpfle, R. Brugnera, M. Balata, A. A. Vasenko, Guillaume Lutter, T. Wester, A. M. Bakalyarov, V. I. Lebedev, A.A. Smolnikov, A. Lazzaro, V. V. Kuzminov, Matteo Agostini, C. Wiesinger, L. Vanhoefer, Thomas Kihm, B. Schneider, Anna Julia Zsigmond, M. Shirchenko, E. Doroshkevich, Manfred Lindner, L. B. Bezrukov, Oliver Schulz, Kai Zuber, C. Macolino, L. Stanco, V. V. Kazalov, E. Shevchik, O.I. Kochetov, G. Zuzel, R. Falkenstein, H. V. Kirpichnikov, Jochen Schreiner, Alberto Pullia, A. Garfagnini, D. R. Zinatulina, O. Selivanenko, V.B. Brudanin, C. Ransom, J. Janicsko, A.-K. Schütz, Hardy Simgen, Werner Hofmann, Allen Caldwell, M. Miloradovic, V. I. Gurentsov, K. N. Gusev, A. Hegai, K. Panas, T. Bode, A. Kish, A. M. Gangapshev, Marcin Wójcik, N. Di Marco, R. Mingazheva, Christian Bauer, A. Lubashevskiy, A. Domula, R. Kneiβl, Cinzia Sada, M. Junker, J. Hakenmüller, P. Grabmayr, B. Schwingenheuer, K. von Sturm, Mikael Hult, R. Hiller, Stefano Riboldi, E. Bellotti, Bayarto Lubsandorzhiev, Stefan Schönert, C. Gooch, P. Moseev, Luciano Pandola, V. Wagner, I. Zhitnikov, I. R. Barabanov, Laura Baudis, M. Misiaszek, A. A. Klimenko, M. Heisel, N. Rumyantseva, F. Salamida, S. V. Zhukov, Alessandro Bettini, B. Cattadori, A. Kirsch, Y. Kermaïdic, V. D'Andrea, Ivano Lippi, L. V. Inzhechik, W. Maneschg, E. A. Yanovich, C. Schmitt, A. V. Veresnikova, A. Chernogorov, J. Jochum Csáthy, A. Wegmann, Igor Nemchenok, Bela Majorovits, E. V. Demidova, and S. Belogurov

Subjects
Paper, Physics, History, Particle physics, Physics - Instrumentation and Detectors, Double beta decay, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment (nucl-ex), Nuclear Experiment, ddc, Computer Science Applications, Education
Abstract

The GERmanium Detector Array (GERDA) experiment located at the INFN Gran Sasso Laboratory (Italy), is looking for the neutrinoless double beta decay of Ge76, by using high-purity germanium detectors made from isotopically enriched material. The combination of the novel experimental design, the careful material selection for radio-purity and the active/passive shielding techniques result in a very low residual background at the Q-value of the decay, about 1e-3 counts/(keV kg yr). This makes GERDA the first experiment in the field to be background-free for the complete design exposure of 100 kg yr. A search for neutrinoless double beta decay was performed with a total exposure of 47.7 kg yr: 23.2 kg yr come from the second phase (Phase II) of the experiment, in which the background is reduced by about a factor of ten with respect to the previous phase. The analysis presented in this paper includes 12.4 kg yr of new Phase II data. No evidence for a possible signal is found: the lower limit for the half-life of Ge76 is 8.0e25 yr at 90% CL. The experimental median sensitivity is 5.8e25 yr. The experiment is currently taking data. As it is running in a background-free regime, its sensitivity grows linearly with exposure and it is expected to surpass 1e26 yr within 2018., 8 pages, to appear in the proceedings of TAUP2017

Published
2020

5. A calorimeter for the precise determination of the activity of the 144Ce-144Pr anti-neutrino source in the SOX experiment

Author

A. Trantel, G. Testera, Paolo Saracco, Matteo Agostini, H. Hess, M. Nieslony, J. Martyn, Lothar Oberauer, Tobias Lachenmaier, Marco Pallavicini, R. Cereseto, Riccardo Musenich, S. Appel, K. Altenmüller, L. Papp, S. Weinz, Stefania Farinon, A. Caminata, S. Rottenanger, L. Di Noto, C. Rossi, Birgit Neumair, Michael Wurm, Luigi Cappelli, S. Schönert, Sandra Zavatarelli, and M. Gschwender

Subjects
Physics, Radiation monitoring, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Detector, 01 natural sciences, Particle detector, Calorimeter, Nuclear physics, Calorimeters, Neutrino detector, Mockup, 0103 physical sciences, High Energy Physics::Experiment, Neutrino, Instrumentation, Mathematical Physics, 010306 general physics, Neutrino oscillation, Borexino
Abstract

We describe the design and the performance of a high precision thermal calorimeter, whose purpose was the measurement of the total activity of the 144Ce-144Pr anti-neutrino source of the SOX (Short distance neutrino Oscillation with BoreXino) experiment. SOX aimed at the search for eV-scale sterile neutrinos by means of the Borexino detector at the Laboratori Nazionali del Gran Sasso in Italy and of a very powerful artificial anti-neutrino source located at 8.51 m from the detector center. In order to obtain the required sensitivity, the activity of the source (approximately 150 kCi) had to be known at 1% precision. In this work we report the design of the experimental apparatus and the results of calibration measurements performed with an electrical mockup of the source. We show that the calorimeter sensitivity exceeds design goals, reaching a precision of a few %.

Published
2018

6. Application of 2D tomographic imaging techniques to edge turbulence in RFX-mod

Author

Paolo Scarin, Roberto Cavazzana, Matteo Agostini, and Gianluigi Serianni

Subjects
52.35.Py, Physics, 52.58.Lq, Tomographic reconstruction, Reversed field pinch, business.industry, Turbulence, Line integral, Condensed Matter Physics, 52.70.-m, Magnetic field, symbols.namesake, Fourier transform, Optics, Nuclear Energy and Engineering, symbols, 52.25.Gj, Light emission, business, Fourier series, 52.35.Ra
Abstract

In the reversed field pinch experiment RFX-mod a gas puffing imaging diagnostic is used to investigate the turbulence of the edge plasma. The system consists of a gas puffing nozzle and 32 optical channels to measure the He I (668 nm) line emission. The lines of sight are arranged into three fans intersecting each other in an area normal to the main magnetic field. The diagnostic system provides an analogue bandwidth of 2 MHz and all channels are simultaneously sampled at 10 Msamples s-1 for the whole discharge duration (350 ms). Different inversion techniques have been applied to the data in order to obtain a 2D tomographic reconstruction of the light emission pattern from the line integrals. Comparison shows that the most precise method is based on the 2D spatial Fourier expansion, applying the singular value decomposition technique with a suitable regularization method to avoid artefacts. The high time resolution allows one to obtain a 2D image every 100 ns. Emission structures ('blobs') that move along the E × B flow emerge from the background turbulence and they are characterized by computing energy and phase of the Fourier modes.

Published
2007

7. Active MHD control at high currents in RFX-mod

Author

Emilio Martines, Lorella Carraro, A. Pizzimenti, D. Terranova, Paolo Franz, M. Brombin, P. Zaccaria, Rita Lorenzini, V. Antoni, E. Spada, Mario Cavinato, Roberto Cavazzana, S. Cappello, G. Rostagni, F. Milani, Paolo Zanca, L. Apolloni, N. Vianello, Vanni Toigo, L. Zanotto, C. Taliercio, N. Pomaro, Gianluca Spizzo, Giuseppe Zollino, Giuseppe Chitarin, C. Taccon, Barbara Zaniol, Federica Bonomo, A. Murari, A. De Lorenzi, Alessandra Canton, Matteo Zuin, Fulvio Auriemma, L. Garzotti, S. Ortolani, R. Paccagnella, S. C. Guo, Anton Soppelsa, Maria Ester Puiatti, Lionello Marrelli, Tommaso Bolzonella, Gabriele Manduchi, F. Sattin, S. Martini, Alessandro Fassina, G. Malesani, Luca Grando, P. Innocente, Giuseppe Marchiori, P. Piovesan, C. Alessi, D. F. Escande, Roberto Pasqualotto, L. De Pasqual, D. Bonfiglio, M. Valisa, Enrico Zilli, A. Cravotta, Paolo Bettini, A. Masiello, Matteo Agostini, R. Piovan, Diego Marcuzzi, G. Gadani, Piergiorgio Sonato, Alberto Alfier, L. Novello, Simone Peruzzo, Elena Gaio, S. Dal Bello, M. Spolaore, Piero Martin, E. Gazza, Francesco Gnesotto, Adriano Luchetta, Leonardo Giudicotti, P. Scarin, A. Buffa, Marco Gobbin, M. Moresco, G. Serianni, Martini, S, Agostini, M, Alessi, C, Alfier, A, Antoni, V, Apolloni, L, Auriemma, F, Bettini, P, Bolzonella, T, Bonfiglio, D, Bonomo, F, Brombin, M, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cavinato, M, Chitarin, G, Cravotta, A, Dal Bello, S, De Lorenzi, A, De Pasqual, L, Escande, D, Fassina, A, Franz, P, Gadani, G, Gaio, E, Garzotti, L, Gazza, E, Giudicotti, L, Gnesotto, F, Gobbin, M, Grando, L, Guo, S, Innocente, P, Lorenzini, R, Luchetta, A, Malesani, G, Manduchi, G, Marchiori, G, Marcuzzi, D, Marrelli, L, Martin, P, Martines, E, Masiello, A, Milani, F, Moresco, M, Murari, A, Novello, L, Ortolani, S, Paccagnella, R, Pasqualotto, R, Peruzzo, S, Piovan, R, Piovesan, P, Pizzimenti, A, Pomaro, N, Puiatti, M, Rostagni, G, Sattin, F, Scarin, P, Serianni, G, Sonato, P, Spada, E, Soppelsa, A, Spizzo, G, Spolaore, M, Taccon, C, Taliercio, C, Terranova, D, Toigo, V, Valisa, M, Vianello, N, Zaccaria, P, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zollino, G, and Zuin, M

Subjects
Physics, Nuclear and High Energy Physics, RFX-mod, Toroid, business.industry, Pulse duration, reversed field pinch, Plasma, Mechanics, Condensed Matter Physics, MHD control, Amplitude, Optics, Physics::Plasma Physics, RFP, Pinch, Magnetohydrodynamics, business, Voltage, Dynamo
Abstract

The modified RFX is a very flexible device used for a variety of control schemes for MHD instabilities and for advanced reverse field pinch scenarios. Relative to the previous machine, RFX-mod has a thin Cu shell with vertical field penetration time τS, lowered from 450 to 50 ms and shell/plasma proximity from b/a ≤ 1.24-1.1. Toroidal equilibrium is feedback-controlled and new power supplies provide better Bφ control. Newly designed graphite tiles protect the vessel from localized power deposition. A mesh of 192 external saddle coils, supervised by a digital feedback system, controls radial fields due to field errors and MHD modes. The paper presents an overview of the very encouraging results obtained using both new and 'standard' advanced operational modes in the current range 0.3-1 MA. A dramatic improvement of plasma performance was obtained by using the saddle coils to cancel all the radial field components, an operation mode dubbed virtual shell (VS). The toroidal voltage was lowered by more than 25% and the pulse length was tripled, up to 7 times the τS. Steady-state RFP pulses are now limited only by the applied volt-seconds. The improved magnetic boundary also has an effect on the tearing modes underlying the sustainment of the RFP, whose core amplitude is more than halved. The VS combined with new schemes for the active rotation of the MHD dynamo modes has allowed us to obtain reliable and well-controlled long RFP pulses in the MA current range. This results in a 100% increase in the particle and energy confinement time relative to the previous experiment and opens the possibility of exploring the machine performance in the 2 MA design range. © 2007 IAEA.

Published
2007

8. Investigation of plasma edge turbulence using a gas-puff imaging system in the reversed-field pinch device TPE-RX

Author

Nicola Vianello, Matteo Agostini, Hajime Sakakita, Y. Hirano, Paolo Scarin, Gianluigi Serianni, Yasuyuki Yagi, Haruhisa Koguchi, Roberto Cavazzana, and Satoru Kiyama

Subjects
Physics, Thermonuclear fusion, Reversed field pinch, Turbulence, business.industry, Plasma parameters, 52.55.Lf, Plasma, Condensed Matter Physics, 52.70.-m, 52.40.Hf, Optics, Nuclear Energy and Engineering, Heat flux, Physics::Plasma Physics, Temporal resolution, Pinch, 52.25.Gj, business, 52.35.Ra
Abstract

An investigation of the edge region in a large reversed-field pinch (RFP) device has been undertaken for the first time using a high time resolution gas-puff imaging (GPI) system, applied to the TPE-RX experiment. The GPI diagnostic is aimed at the investigation of turbulence in the edge region under the severe heat flux conditions of thermonuclear fusion-grade plasmas, where conventional electrostatic probes cannot be used. To compare the data obtained by the GPI during low power experiments, a retractable array of electrostatic probes has been added. The whole diagnostic system provided high quality measurements of fluctuations with fine spatial and temporal resolution, as well as radial profiles of relevant plasma parameters. The measurements confirm several important properties of plasma edge already found in other experiments, like the presence of a strong ExB shear layer and the 'intermittent' behaviour of the measured quantities, which display non-Gaussian fluctuation spikes at different time scales. Along with the conventional power spectra and correlation analyses, the application of continuous wavelet transform techniques to GPI data allowed a detailed description of the spatial structure and of the propagation of these localized 'intermittent events'.

Published
2007

9. Statistical features of edge turbulence in RFX-mod from gas puffing imaging

Author

Nicola Vianello, Gianluigi Serianni, P. Scarin, Matteo Agostini, Fabio Sattin, M. Spolaore, and R. Cavazzana

Subjects
Physics, DIII-D, Turbulence, Gaussian, FOS: Physical sciences, Probability density function, Plasma, SCRAPE-OFF LAYER, SINGLE HELICITY, Condensed Matter Physics, Physics - Plasma Physics, Computational physics, Plasma Physics (physics.plasm-ph), symbols.namesake, Nuclear Energy and Engineering, REVERSED-FIELD PINCH, Simple function, Phenomenological model, symbols, PLASMA TURBULENCE, Gamma function, Linear combination
Abstract

Plasma density fluctuations in the edge plasma of the RFX-mod device are measured through the Gas Puffing Imaging Diagnostics. Statistical features of the signal are quantified in terms of the Probability Distribution Function (PDF), and computed for several kinds of discharges. The PDFs from discharges without particular control methods are found to be adequately described by a Gamma function, consistently with the recent results by Graves et al [J.P. Graves, et al, Plasma Phys. Control. Fusion 47, L1 (2005)]. On the other hand, pulses with external methods for plasma control feature modified PDFs. A first empirical analysis suggests that they may be interpolated through a linear combination of simple functions. An inspection of the literature shows that this kind of PDFs is common to other devices as well, and has been suggested to be due to the simultaneous presence of different mechanisms driving respectively coherent bursts and gaussian background turbulence. An attempt is made to relate differences in the PDFs to plasma conditions such as the local shift of the plasma column. A simple phenomenological model to interpret the nature of the PDF and assign a meaning to its parameters is also developed., Comment: 27 pages. Published in PPCF

Published
2006

10. First results from GERDA Phase II

Author

Manfred Lindner, V. I. Gurentsov, Cinzia Sada, Giovanni Benato, E. Bellotti, V. V. Kazalov, D. Borowicz, Bayarto Lubsandorzhiev, O. Selivanenko, E. Doroshkevich, J. Hakenmüller, Christian Bauer, C. Macolino, J. Janicskó Csáthy, A. Lubashevskiy, L. B. Bezrukov, E. Shevchik, K. T. Knöpfle, R. Mingazheva, R. Brugnera, V. V. Kuzminov, Marcin Wójcik, Matteo Agostini, P. Grabmayr, Werner Hofmann, J. Jochum, L. Stanco, B. Schwingenheuer, Allen Caldwell, O.I. Kochetov, V. Wagner, I. Zhitnikov, A. Wegmann, Alessandro Bettini, B. Lehnert, Igor Nemchenok, A. Kirsch, V.B. Brudanin, G. Zuzel, D. Palioselitis, V. N. Kornoukhov, M. Allardt, Stefano Riboldi, W. Maneschg, Hardy Simgen, E. A. Yanovich, S. T. Belyaev, V. G. Egorov, M. Balata, C. Schmitt, E. Medinaceli, K. Pelczar, K. Panas, A. M. Gangapshev, T. Wester, A.A. Smolnikov, A. Lazzaro, Bela Majorovits, L. V. Inzhechik, P. Moseev, C. Cattadori, Kai Zuber, Guillaume Lutter, A. M. Bakalyarov, L. Vanhoefer, Luciano Pandola, M. Misiaszek, A. A. Klimenko, C. Wiesinger, K. von Sturm, Thomas Kihm, M. Heisel, N. Rumyantseva, M. Shirchenko, Laura Baudis, A. Kish, E. V. Demidova, I. R. Barabanov, A. Domula, F. Salamida, C. Gooch, S. V. Zhukov, A.-K. Schütz, R. Falkenstein, A. Hegai, M. Junker, V. D'Andrea, Jochen Schreiner, N. Di Marco, T. Bode, S. Belogurov, V. I. Lebedev, M. Salathe, Ivano Lippi, D. R. Zinatulina, H. Y. Liao, A. V. Veresnikova, Mikael Hult, A. Chernogorov, S. Hemmer, I. V. Kirpichnikov, M. Miloradovic, B. Schneider, R. Kneißl, K. N. Gusev, Stefan Schönert, Matthias Laubenstein, A. A. Vasenko, N. Frodyma, Oliver Schulz, Alberto Pullia, and A. Garfagnini

Subjects
Nuclear physics, Physics, Semileptonic decay, History, Phase (matter), Nuclear Matrix, Beta Decay, Bolometers, Beta Decay, Bolometers, Nuclear Matrix, Computer Science Applications, Education
Published
2017

11. Active background suppression with the liquid argon scintillation veto of GERDA Phase II

Author

O.I. Kochetov, Oliver Schulz, L. B. Bezrukov, M. Salathe, K. Panas, A. M. Bakalyarov, E. V. Demidova, A. Chernogorov, A. Wegmann, Alberto Pullia, Igor Nemchenok, Christian Bauer, Bela Majorovits, K. Pelczar, S. T. Belyaev, A. Kish, A. Lubashevskiy, D. Palioselitis, D. R. Zinatulina, A. Domula, A. M. Gangapshev, A. Garfagnini, I. R. Barabanov, Guillaume Lutter, C. Gooch, S. V. Zhukov, I. V. Kirpichnikov, B. Lehnert, A.-K. Schütz, Th. Kihm, A. Hegai, Mikael Hult, V. G. Egorov, M. Balata, C. Schmitt, N. Di Marco, M. Allardt, C. Cattadori, L. Stanco, J. Janicskó Csáthy, P. Moseev, L. V. Inzhechik, Luciano Pandola, Ivano Lippi, S. Hemmer, M. Miloradovic, K. N. Gusev, L. Vanhoefer, A. A. Klimenko, V.B. Brudanin, V.N. Kornoukhov, M. Heisel, C. Macolino, Hardy Simgen, R. Falkenstein, Jochen Schreiner, C. Wiesinger, K. T. Knöpfle, N. Rumyantseva, S. Belogurov, R. Brugnera, Manfred Lindner, M. Shirchenko, Matthias Laubenstein, E. Bellotti, E. Doroshkevich, V. V. Kuzminov, B. Schneider, Stefan Schönert, N. Frodyma, M. Junker, Matteo Agostini, V. Wagner, I. Zhitnikov, Laura Baudis, A. V. Veresnikova, O. Selivanenko, Alessandro Bettini, V. I. Lebedev, R. Mingazheva, Cinzia Sada, Marcin Wójcik, P. Grabmayr, B. Schwingenheuer, E. Medinaceli, T. Bode, J. Jochum, H. Y. Liao, Giovanni Benato, V. Kazalov, Stefano Riboldi, M. Misiaszek, V. I. Gurentsov, Bayarto Lubsandorzhiev, E. Shevzik, R. Kneißl, A. Kirsch, W. Maneschg, E. A. Yanovich, V. D'Andrea, A. A. Vasenko, Allen Caldwell, K. von Sturm, Werner Hofmann, D. Borowicz, J. Hakenmüller, T. Wester, A.A. Smolnikov, A. Lazzaro, Kai Zuber, G. Zuzel, and F. Salamida

Subjects
Physics, History, Scintillation, Argon, 010308 nuclear & particles physics, Veto, chemistry.chemical_element, 01 natural sciences, Particle detector, Computer Science Applications, Education, Semiconductor detector, Nuclear physics, chemistry, Impurity, Phase (matter), 0103 physical sciences, Scintillation counter, DETECTORS, 010306 general physics
Published
2017

12. Overview of the RFX-mod fusion science activity

Author

A. De Lorenzi, Rita Lorenzini, F. Belli, Andrea Rizzolo, Luca Stevanato, O. McCormack, Paolo Scarin, D. F. Escande, J. S. Sarff, M. Bigi, Y. Zhang, Alessandro Fassina, L. Piron, N. Vianello, M. E. Puiatti, Roberto Paccagnella, Fabio Villone, Piergiorgio Sonato, Nicola Pilan, Emilio Martines, James D. Hanson, C. Taliercio, A. Zamengo, M. Recchia, L. Giudicotti, M. Vallar, J.Q. Dong, M. Dalla Palma, Daniele Bonfiglio, Paolo Franz, Matthias Komm, Luis Chacon, Satoru Kiyama, N. Visona, M. Siragusa, L. Zanotto, Paolo Bettini, D. Terranova, Raul Sanchez, Roscoe White, S. Dal Bello, M. Brombin, Enrico Zilli, Francesco Gnesotto, Yueqiang Liu, S.P. Hirshman, L. Pigatto, S. Martini, Piero Martin, M. Pavei, Nisarg Patel, Alessandra Canton, Lorenzo Frassinetti, Matteo Zuin, T. Bolzonella, G. Urso, Chenguang Li, Oliver Schmitz, C. Finotti, Paolo Zanca, Chiara Bustreo, Silvia Spagnolo, M. Veranda, M. Baruzzo, V. Antoni, T. Barbui, Hajime Sakakita, Pavlos Xanthopoulos, Wolf-Dieter Schneider, Nicolò Marconato, Yoshiro Narushima, W. A. Cooper, G. Pucella, Piero Agostinetti, Lionello Marrelli, B. Liu, B. Momo, Simone Peruzzo, X. Y. Xu, Elena Gaio, M. Moresco, Francesco Ghezzi, Y. Suzuki, C. Piron, O. Tudisco, Susanna Cappello, P. Piovesan, Adriano Luchetta, A. Maistrello, F. Sattin, M. Boldrin, Donald A. Spong, A. Buffa, L. Cordaro, V. Yanovskiy, R. Cavazzana, Cristina Rea, W. Gonzalez, Matteo Agostini, R. Piovan, Songfen Liu, Giuseppe Chitarin, G. Rostagni, S. M. Deambrosis, Alberto Ferro, O. Kudlacek, M. Spolaore, Gianluca Spizzo, Paolo Innocente, Italo Predebon, G. Mazzitelli, Marco Gobbin, D. Cester, J. L. Jackson, Laszlo Sajo-Bohus, M. Valente, T.C. Luce, L. Laguardia, Diego Marcuzzi, Fulvio Auriemma, Giuseppe Marchiori, P. Vincenzi, D.K. Mansfield, E. Spada, M. Valisa, G. De Masi, Gabriele Manduchi, Lorella Carraro, E. Miorin, M. Okabayashi, S. C. Guo, Barbara Zaniol, R. Delogu, D. Lopez-Bruna, Marco Barbisan, Faa Federico Felici, Cristian Ruset, Luca Grando, R. Bilel, Mazzitelli, G., Tudisco, O., Pucella, G., Zuin, M, DAL BELLO, S, Marrelli, L, Puiatti, M, Agostinetti, P, Agostini, M, Antoni, V, Auriemma, F, Barbisan, M, Barbui, T, Baruzzo, M, Belli, F, Bettini, P, Bigi, M, Bilel, R, Boldrin, M, Bolzonella, T, Bonfiglio, D, Brombin, M, Buffa, A, Bustreo, C, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cester, D, Chacon, L, Chitarin, G, Cooper, W, Cordaro, L, DALLA PALMA, M, Deambrosis, S, Delogu, R, De Lorenzi, A, DE MASI, G, Dong, J, Escande, D, Fassina, A, Felici, F, Ferro, A, Finotti, C, Franz, P, Frassinetti, L, Gaio, E, Ghezzi, F, Giudicotti, L, Gnesotto, F, Gobbin, M, Gonzalez, W, Grando, L, Guo, S, Hanson, J, Hirshman, S, Innocente, P, Jackson, J, Kiyama, S, Komm, M, Kudlacek, O, Laguardia, A, Li, C, Liu, B, Liu, S, Liu, Y, López Bruna, D, Lorenzini, R, Luce, T, Luchetta, A, Maistrello, A, Manduchi, G, Mansfield, D, Marchiori, G, Marconato, N, Marcuzzi, D, Martin, P, Martines, E, Martini, S, Mazzitelli, G, Mccormack, O, Miorin, E, Momo, B, Moresco, M, Narushima, Y, Okabayashi, M, Paccagnella, R, Patel, N, Pavei, M, Peruzzo, S, Pilan, N, Pigatto, L, Piovan, R, Piovesan, P, Piron, C, Piron, L, Predebon, I, Pucella, G, Rea, C, Recchia, M, Rizzolo, A, Rostagni, G, Ruset, C, Sajò Bohus, L, Sakakita, H, Sanchez, R, Sarff, J, Sattin, F, Scarin, P, Schmitz, O, Schneider, W, Siragusa, M, Sonato, P, Spada, E, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Stevanato, L, Suzuki, Y, Taliercio, C, Terranova, D, Tudisco, O, Urso, G, Valente, M, Valisa, M, Vallar, M, Veranda, M, Vianello, N, Villone, F, Vincenzi, P, Visonà, N, White, R, Xanthopoulos, P, Xu, X, Yanovskiy, V, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zhang, Y, and Zilli, E

Subjects
Nuclear and High Energy Physics, Guiding center, Tokamak, MHD, single helicity, reversed field pinch, runaway electron, 01 natural sciences, 010305 fluids & plasmas, law.invention, 3D boundary, Physics::Plasma Physics, law, Electric field, 0103 physical sciences, 010306 general physics, PWI, tokamak, reversed field pinch, tokamak, single helicity, 3D boundary, runaway electrons, MHD, PWI, Physics, Reversed field pinch, runaway electrons, Plasma, Condensed Matter Physics, Computational physics, Magnet, ingle helicity, Pinch, Atomic physics, Magnetohydrodynamics
Abstract

This paper reports the main recent results of the RFX-mod fusion science activity. The RFX-mod device is characterized by a unique flexibility in terms of accessible magnetic configurations. Axisymmetric and helically shaped reversed-field pinch equilibria have been studied, along with tokamak plasmas in a wide range of q(a) regimes (spanning from 4 down to 1.2 values). The full range of magnetic configurations in between the two, the so-called ultra-low q ones, has been explored, with the aim of studying specific physical issues common to all equilibria, such as, for example, the density limit phenomenon. The powerful RFX-mod feedback control system has been exploited for MHD control, which allowed us to extend the range of experimental parameters, as well as to induce specific magnetic perturbations for the study of 3D effects. In particular, transport, edge and isotope effects in 3D equilibria have been investigated, along with runaway mitigations through induced magnetic perturbations. The first transitions to an improved confinement scenario in circular and D-shaped tokamak plasmas have been obtained thanks to an active modification of the edge electric field through a polarized electrode. The experiments are supported by intense modeling with 3D MHD, gyrokinetic, guiding center and transport codes. Proposed modifications to the RFX-mod device, which will enable further contributions to the solution of key issues in the roadmap to ITER and DEMO, are also briefly presented. © 2017 IAEA, Vienna.

Published
2017

13. Edge plasma properties with 3D magnetic perturbations in RFX-mod

Author

P. Scarin, Monica Spolaore, Gianluca Spizzo, M. Veranda, Susanna Cappello, N. Vianello, Matteo Agostini, M. Zuin, Fulvio Auriemma, L. Carraro, Silvia Spagnolo, Lionello Marrelli, and RFX-mod Team

Subjects
Nuclear and High Energy Physics, Tokamak, Reversed field pinch, Electron, Plasma, 3D magnetic field, Condensed Matter Physics, 01 natural sciences, Instability, Helicity, 010305 fluids & plasmas, law.invention, Magnetic field, Physics::Plasma Physics, law, 0103 physical sciences, magnetic perturbations, edge plasma, Atomic physics, 010306 general physics, Pressure gradient
Abstract

The response of the edge plasma to a magnetic perturbation (MP) is studied in the RFX-mod device, in both reversed field pinch (RFP) and tokamak discharges. The use of spatially distributed diagnostics, in particular along the poloidal direction, allows a direct 3D characterization of the plasma. It is shown that there is a difference between the spectrum of the MP and that of different properties of the edge plasma, such as the floating potential, the electron pressure and the flow, for both RFP and tokamak plasmas. In particular, for RFP cases, even if the magnetic perturbation is mainly m = 1, with the amplitude of the m = 0 and m = 2 sidebands negligible, the connection length to the wall of the magnetic field L cw has a more complex structure. The ergodic regions, with L cw larger than the Kolmogorov length, are due to the interaction of both m = 1 and m = 0 modes, showing a complex and non-monochromatic behaviour along the poloidal angle. This structure of L cw is responsible for the impure m = 1 behaviour of the plasma wall interaction, floating potential and electron pressure. Thus the helicity of the edge plasma is quite different from that of the dominant MP.

Published
2017

14. On the statistics and features of turbulent structures in RFX-mod

Author

Matteo Agostini, M. Zuin, Emilio Martines, Silvia Spagnolo, P. Scarin, B. Momo, G. De Masi, N. Vianello, Roberto Cavazzana, Monica Spolaore, Vianello, N, Spolaore, M, Agostini, M, Cavazzana, R, De Masi, G, Martines, E, Momo, B, Scarin, P, Spagnolo, S, and Zuin, M

Subjects
Tokamak, Similarity (geometry), K-epsilon turbulence model, blobs, reversed field pinch, Enstrophy, 01 natural sciences, 010305 fluids & plasmas, law.invention, Physics::Fluid Dynamics, Physics::Plasma Physics, law, 0103 physical sciences, Statistical physics, 010306 general physics, tokamak, Physics, Reversed field pinch, Turbulence, blob, turbulence, Condensed Matter Physics, Computational physics, Nonlinear Sciences::Chaotic Dynamics, Nuclear Energy and Engineering, Beta (plasma physics), Energy (signal processing)
Abstract

An extensive statistical characterization of the electromagnetic turbulence in the edge region of RFX-mod, operated as a tokamak and as a Reversed Field Pinch, is presented. Striking similarity are observed on the intermittent character of the electrostatic turbulence between the two configurations whereas the difference between magnetic turbulence is likely to be imputed to the different beta value of the two configurations. Blobs are characterized in terms of their spatial structure, the associated enstrophy and energy and the mechanism of energy and enstrophy transfer between intermittent fluctuation at different scales is addressed.

Published
2016

15. Geo-neutrino results with Borexino

Author

B. Lehnert, L. Papp, A.V. Etenko, G. Bonfini, A. Caminata, Fausto Ortica, Marco Pallavicini, F. Gabriele, Y. Suvorov, I. N. Machulin, D. Bravo, Livia Ludhova, D. D'Angelo, S. Weinz, A. M. Goretti, Frank Calaprice, A. S. Chepurnov, M. D. Skorokhvatov, Hardy Simgen, Michael Wurm, Matthias Laubenstein, P. J. Mosteiro, Michele Montuschi, S. Schönert, O. Smirnov, F. von Feilitzsch, E. Litvinovich, Denis Korablev, D. A. Semenov, F. Lombardi, M. S. Meyer, N. Rossi, E. V. Hungerford, Marco Giammarchi, A. Razeto, E. V. Unzhakov, C. Ghiano, S. Appel, Andrea Ianni, D. Bick, Sandra Zavatarelli, A. Sotnikov, Caren Hagner, R Roncin, E. Meroni, K. Jedrzejczak, R. B. Vogelaar, Kai Zuber, J. Winter, Lino Miramonti, Paolo Lombardi, P. Cavalcante, R. Tartaglia, Matteo Agostini, A. V. Derbin, Z. Yokley, D. Franco, B. Neumair, M. Misiaszek, I. S. Drachnev, S. V. Sukhotin, B. Caccianiga, G. Korga, K. Fomenko, Jay Burton Benziger, Marcin Wójcik, Aldo Romani, O. Zaimidoroga, G. Testera, H. Wang, L. Di Noto, W. Maneschg, L. Perasso, G. Zuzel, M. Goeger-Neff, Gioacchino Ranucci, G. Bellini, Lothar Oberauer, V. V. Kobychev, Aldo Ianni, M. Gromov, M. Obolensky, G. Lukyanchenko, V. N. Muratova, A. Pocar, D. Kryn, S. Manecki, M. Kaiser, J. Thurn, Cristiano Galbiati, Alessandra Re, S. Davini, A. Vishneva, S. Marcocci, M. Toropova, AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Borexino, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Roncin, R., Agostini, M., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Noto, L., Drachnev, I., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Muratova, V., Neumair, B., Oberauer, L., Obolensky, M., Ortica, F., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Rossi, N., Schoenert, S., Semenov, D., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vishneva, A., Vogelaar, R. B., von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., Zuzel, G., and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)

Subjects
History, 010504 meteorology & atmospheric sciences, Solar neutrino, scintillation counter: liquid, chemistry.chemical_element, Scintillator, 010502 geochemistry & geophysics, 7. Clean energy, 01 natural sciences, thorium, Education, uranium, Nuclear physics, Physics and Astronomy (all), background: low, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Borexino, 0105 earth and related environmental sciences, Physics, Radionuclide, Radiogenic nuclide, Thorium, Mass ratio, nuclide: mass ratio, Computer Science Applications, chemistry, 13. Climate action, radioactivity, GEOPHYSICS, neutrino: geophysics, Neutrino, experimental results
Abstract

International audience; Borexino is a liquid scintillator detector primary designed to observe solar neutrinos. Due to its low background level as well as its position in a nuclear free country, Italy, Borexino is also sensitive to geo-neutrinos. Borexino is leading this interdisciplinary field of neutrino geoscience by studying electron antineutrinos which are emitted from the decay of radioactive isotopes present in the crust and the mantle of the Earth. With 2056 days of data taken between December 2007 and March 2015, Borexino observed 77 antineutrino candidates. If we assume a chondritic Th/U mass ratio of 3.9, the number of geo-neutrino events is found to be 23.7(+6.5) (-5.7)(stat) (+0.9)(-0.6) (syst). With this measurement, Borexino alone is able to reject the null geo-neutrino signal at 5.9σ, to claim a geo-neutrino signal from the mantle at 98% C.L. and to restrict the radiogenic heat production for U and Th between 23 and 36 TW.

Published
2016

16. Test of the electric charge conservation law with Borexino detector

Author

Z. Yokley, M. D. Skorokhvatov, Michael Wurm, D. A. Semenov, Kai Zuber, Cristiano Galbiati, L. Perasso, O. Smirnov, E. V. Unzhakov, S. Manecki, G. Bellini, Lothar Oberauer, E. Litvinovich, F. von Feilitzsch, S. V. Sukhotin, O. Zaimidoroga, N. Rossi, H. Wang, R. Tartaglia, Matthias Laubenstein, A.V. Etenko, G. Lukyanchenko, D. Bravo, Matteo Agostini, K. Jedrzejczak, V. V. Kobychev, A. Vishneva, Marcin Wójcik, M. Gromov, B. Neumair, P. J. Mosteiro, D. D 'Angelo, Michele Montuschi, Lino Miramonti, Gioacchino Ranucci, G. Korga, K. Fomenko, L. Papp, W. Maneschg, B. Lehnert, M. Obolensky, E. Meroni, S. Marcocci, E. V. Hungerford, Fausto Ortica, M. Toropova, V. N. Muratova, S. Davini, S. Weinz, A. Sotnikov, A. Pocar, A. Caminata, Marco Pallavicini, C. Ghiano, F. Gabriele, Caren Hagner, M. S. Meyer, S. Schönert, M. Goeger-Neff, P. Cavalcante, Marco Giammarchi, M. Misiaszek, G. Bonfini, D. Kryn, Paolo Lombardi, Jay Burton Benziger, J. Winter, Andrea Ianni, D. Bick, Sandra Zavatarelli, F. Lombardi, Frank Calaprice, G. Zuzel, M. Kaiser, D. Franco, A. V. Derbin, Hardy Simgen, A. Razeto, I. S. Drachnev, I. N. Machulin, S. Appel, G. Testera, Denis Korablev, B. Caccianiga, Y. Suvorov, Livia Ludhova, A. M. Goretti, A. S. Chepurnov, R. B. Vogelaar, Aldo Ianni, Aldo Romani, L. Di Noto, Alessandra Re, J. Thurn, R. Roncin, AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Borexino, Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Vishneva, A., Agostini, M., Appel, S., Bellini, G., Benziger, J., Bick, D., Bonfini, G., Bravo, D., Caccianiga, B., Calaprice, F., Caminata, A., Cavalcante, P., Chepurnov, A., D'Angelo, D., Davini, S., Derbin, A., Di Noto, L., Drachnev, I., Etenko, A., Fomenko, K., Franco, D., Gabriele, F., Galbiati, C., Ghiano, C., Giammarchi, M., Goeger-Neff, M., Goretti, A., Gromov, M., Hagner, C., Hungerford, E., Ianni, Aldo, Ianni, Andrea, Jedrzejczak, K., Kaiser, M., Kobychev, V., Korablev, D., Korga, G., Kryn, D., Laubenstein, M., Lehnert, B., Litvinovich, E., Lombardi, F., Lombardi, P., Ludhova, L., Lukyanchenko, G., Machulin, I., Manecki, S., Maneschg, W., Marcocci, S., Meroni, E., Meyer, M., Miramonti, L., Misiaszek, M., Montuschi, M., Mosteiro, P., Muratova, V., Neumair, B., Oberauer, L., Obolensky, M., Ortica, F., Pallavicini, M., Papp, L., Perasso, L., Pocar, A., Ranucci, G., Razeto, A., Re, A., Romani, A., Roncin, R., Rossi, N., Schoenert, S., Semenov, D., Simgen, H., Skorokhvatov, M., Smirnov, O., Sotnikov, A., Sukhotin, S., Suvorov, Y., Tartaglia, R., Testera, G., Thurn, J., Toropova, M., Unzhakov, E., Vogelaar, R. B., Von Feilitzsch, F., Wang, H., Weinz, S., Winter, J., Wojcik, M., Wurm, M., Yokley, Z., Zaimidoroga, O., Zavatarelli, S., Zuber, K., Zuzel, G., Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
GRAN SASSO, +photon+neutrino%22">electron --> photon neutrino, History, Physics::Instrumentation and Detectors, scintillation counter: liquid, Electron, Scintillator, 01 natural sciences, Particle detector, Physics::Geophysics, Education, Nuclear physics, SCINTILLATOR, Physics and Astronomy (all), background: low, 0103 physical sciences, charge: conservation law, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], ddc:530, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 010303 astronomy & astrophysics, Borexino, lifetime, Physics, Charge conservation, STABILITY, 010308 nuclear & particles physics, Detector, EXPERIMENTAL LIMITS, Computer Science Applications, Neutrino detector, electron: lifetime, Neutrino, DECAY
Abstract

International audience; The new limit on the electron lifetime is obtained from data of the Borexino experiment. The expected signal from the e → γν decay mode is a 256 keV photon detected in liquid scintillator. Because of the extremely low radioactive background level in the Borexino detector it was possible to improve the previous measurement by two orders of magnitude.

Published
2016

17. Off-line data processing and analysis for the GERDA experiment

Author

Matteo Agostini, P. Zavarise, and Luciano Pandola

Subjects
History, Data processing, Signal processing, Physics - Instrumentation and Detectors, business.industry, Computer science, Detector, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Modular design, High Energy Physics - Experiment, Computer Science Applications, Education, Semiconductor detector, ddc, High Energy Physics - Experiment (hep-ex), Physics - Data Analysis, Statistics and Probability, Double beta decay, Nuclear Experiment (nucl-ex), Coaxial, business, Nuclear Experiment, Digital filter, Data Analysis, Statistics and Probability (physics.data-an), Computer hardware
Abstract

GERDA is an experiment designed to look for the neutrinoless double beta decay of Ge-76. The experiment uses an array of high-purity germanium detectors, enriched in Ge-76, directly immersed in liquid argon. GERDA is presently operating eight enriched coaxial detectors (approximately 15 kg of Ge-76) and about 30 new custom-made enriched BEGe detectors will be deployed in the next phase (additional 20 kg of Ge-76). The paper describes the GERDA off-line analysis of the high-purity germanium detector data. Firstly we present the signal processing flow, focusing on the digital filters and on the algorithms used. Secondly we discuss the rejection of non-physical events and the data quality monitoring. The analysis is performed completely with the GERDA software framework (GELATIO), designed to support a multi-channel processing and to perform a modular analysis of digital signals., 7 pages, 7 figures, ACAT 2011 proceeding

Published
2011

18. The MGDO software library for data analysis in Ge neutrinoless double-beta decay experiments

Author

D. Lenz, P. Zavarise, Kevin Kröninger, Matteo Agostini, Alexis G. Schubert, K. D. Nguyen, O. Volynets, R. D. Martin, Michael G. Marino, J. A. Detwiler, Luciano Pandola, Jing Liu, and P. Finnerty

Subjects
History, Computer science, FOS: Physical sciences, 01 natural sciences, High Energy Physics - Experiment, Education, Computational science, Set (abstract data type), High Energy Physics - Experiment (hep-ex), Software, Conceptual design, Double beta decay, 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, 010308 nuclear & particles physics, business.industry, Detector, 3. Good health, Computer Science Applications, ddc, MAJORANA, Physics - Data Analysis, Statistics and Probability, Programming paradigm, Data analysis, business, Data Analysis, Statistics and Probability (physics.data-an)
Abstract

The GERDA and Majorana experiments will search for neutrinoless double-beta decay of germanium-76 using isotopically enriched high-purity germanium detectors. Although the experiments differ in conceptual design, they share many aspects in common, and in particular will employ similar data analysis techniques. The collaborations are jointly developing a C++ software library, MGDO, which contains a set of data objects and interfaces to encapsulate, store and manage physical quantities of interest, such as waveforms and high-purity germanium detector geometries. These data objects define a common format for persistent data, whether it is generated by Monte Carlo simulations or an experimental apparatus, to reduce code duplication and to ease the exchange of information between detector systems. MGDO also includes general-purpose analysis tools that can be used for the processing of measured or simulated digital signals. The MGDO design is based on the Object-Oriented programming paradigm and is very flexible, allowing for easy extension and customization of the components. The tools provided by the MGDO libraries are used by both GERDA and Majorana., 4 pages, 1 figure, proceedings for TAUP2011

Published
2011

19. Characterization of particle confinement properties in RFX-mod at a high plasma current

Author

Rita Lorenzini, Paolo Scarin, Emilio Martines, Marco Gobbin, Fulvio Auriemma, Alessandro Fassina, Matteo Zuin, Lorella Carraro, Matteo Agostini, Paolo Innocente, Wolf-Dieter Schneider, G. De Masi, Auriemma, F, Lorenzini, R, Agostini, M, Carraro, L, De Masi, G, Fassina, A, Gobbin, M, Martines, E, Innocente, P, Scarin, P, Schneider, W, and Zuin, M

Subjects
Physics, stochastic transport, Nuclear and High Energy Physics, transport analysis, Tokamak, edge turbulence, Radius, Plasma, Electron, Condensed Matter Physics, Thermal diffusivity, law.invention, Physics::Plasma Physics, law, particle confinement, transport analysi, Pinch, Atomic physics, Transport phenomena, particle source, Plasma-facing material
Abstract

Transport phenomena affect the performance of fusion devices, reducing heat and particle confinement and consequently leading to a lower fusion triple product and higher fluxes on the plasma facing material. Special attention is devoted in the fusion community to the study of transport mitigation phenomena which lead to the onset of transport barriers in tokamaks, stellarators and reverse field pinch plasmas. The aim of this study is to deepen our understanding of the mechanisms driving transport in the presence of electron internal transport barriers in the RFX-mod single helical axis (SHAx) state (Lorenzini et al 2009 Nature Phys. 5 570). We discuss whether transport in the core can be described within the theory of chaotic transport. Light is also shed on the mechanisms acting at the plasma edge. The particle source is calculated using the 2D Monte-Carlo code NENE, considering the pattern of plasma-wall interaction. In the core region of the SHAx we found that the diffusivity along 90% of the radius is reduced with respect to the standard case: D similar to 1 m(2) s(-1) fits well with the density profile, compared with the similar to 50 m(2) s(-1) of a standard plasma. This result confirms a strong mitigation of magnetic chaos, although comparison with the neoclassical diffusivity D-neo similar to 0.01-0.4 m(2) s(-1) indicates that transport in the SHAx is still anomalous. The same picture describes well both the particle and energy transport in the plasma core: comparison with the effective thermal diffusivity chi(eff) indicates that the ratio chi(eff)/D similar to (m(i)/m(e))(0.5) is consistent with the theory of chaos-dominated transport. The plasma edge is affected by a different mechanism. In the external region (the final 10% of the radius) magnetic chaos is suppressed and the edge diffusivity is likely to be ruled by electrostatic turbulence, in particular a direct link with the presence of pressure coherent structures is found.

Published
2015

20. Parallel and perpendicular structure of the edge turbulence in a three-dimensional magnetic field

Author

Gianluca Spizzo, Lorella Carraro, N. Vianello, Paolo Scarin, and Matteo Agostini

Subjects
Physics, Electron density, Reversed field pinch, Condensed matter physics, Plane (geometry), Turbulence, 3D magnetic field, Edge (geometry), Condensed Matter Physics, edge blobs, Magnetic field, edge fluctuations, Nuclear Energy and Engineering, Physics::Plasma Physics, plasma turbulence, RFP, Perpendicular, Topology (chemistry)
Abstract

Edge turbulence and blobs are studied in the three-dimensional magnetic topology of the RFX-mod reversed field pinch. The edge of the RFX-mod shows a three-dimensional structure dominated by a helical equilibrium with (1, -7) symmetry, which gives the same space-time modulation to all of the kinetic properties. The interaction between the edge turbulence and this magnetic topology is studied. It is shown that the edge blobs are current-carrying filaments aligned with the magnetic field, and in the perpendicular plane each blob is a positive peak of electron density and a valley of temperature. The inner nature of these blobs is not affected by the presence of the O and X points of the (1, -7) island; however, the statistical properties are sensitive to them, pointing to the influence of the magnetic topology on the edge fluctuations.

Published
2014

21. Overview of the RFX-mod fusion science programme

Author

Piergiorgio Sonato, S. Dal Bello, Maria Ester Puiatti, Piero Martin, A. Fiorentin, Stefano Munaretto, F. Fellin, G. De Masi, M. Gobbin, Silvia Spagnolo, M. Furno Palumbo, P. Zaccaria, E. Gazza, M. Recchia, Raul Sanchez, Karsten McCollam, G. L. Trevisan, E. Spada, Alessandra Canton, Matteo Zuin, Ivo Furno, Christian Theiler, A. Zamengo, J.Q. Dong, Emilio Martines, B. E. Chapman, M. Dalla Palma, Paolo Franz, M. Brombin, V. Rigato, J. Framarin, Antonio Barbalace, P. Piovesan, Nicola Pilan, Donald A. Spong, Roberto Paccagnella, Wolf-Dieter Schneider, Barbara Zaniol, Fabio Villone, Leonardo Giudicotti, M. De Muri, T.C. Luce, R. Piovan, A. Ruzzon, V. Antoni, Giuseppe Zollino, Emanuele Sartori, Yueqiang Liu, G. Rostagni, M. Baruzzo, Manabu Takechi, Yongkyoon In, R. Delogu, Fulvio Auriemma, J. A. Alonso, M. Barp, C. Piron, D. Bonfiglio, Go Matsunaga, Enrico Zilli, G. Ciaccio, S. Martini, L. Piron, Marco Barbisan, Songfen Liu, M. Veranda, A. Scaggion, Giuseppe Chitarin, N. Pomaro, Luis Chacon, James D. Hanson, L. Apolloni, Yoichi Hirano, M. Spolaore, Francesco Gnesotto, F. Avino, Nicolò Marconato, M. Valente, Alberto Ferro, Fabio Sattin, Pierluigi Veltri, Gabriele Manduchi, L. Zanotto, C. Hidalgo, Paolo Innocente, Simona Barison, L. Novello, Italo Predebon, Rita Lorenzini, David Terranova, Luca Grando, Zhirui Wang, Vanni Toigo, M. Boldrin, M. Bigi, Adriano Luchetta, Paolo Bettini, Erik Olofsson, Andrea Rizzolo, Gianluigi Serianni, Anton Soppelsa, Cesare Taliercio, Roscoe White, C. Finotti, Susanna Cappello, N. Fonnesu, Roberto Pasqualotto, Paolo Scarin, R. Bilel, Shunsuke Ide, Alessandro Fassina, A. Maistrello, D. Carralero, Matteo Agostini, W. A. Cooper, P. Zanca, A. Buffa, Piero Agostinetti, G. Mazzitelli, X. Y. Xu, S. Fiameni, M. Moresco, John M. Finn, Lionello Marrelli, B. Momo, Tommaso Bolzonella, Nicola Vianello, Giuseppe Marchiori, D.K. Mansfield, M. Valisa, M. Okabayashi, S. C. Guo, Dominique Escande, Lorella Carraro, A. Pesce, M. Pavei, F. Ghezzi, Roberto Cavazzana, Satoru Kiyama, W. A. Gonzales, Simone Peruzzo, S.P. Hirshman, Elena Gaio, T. Barbui, Hajime Sakakita, G.L. Jackson, J. S. Sarff, Ambrogio Fasoli, D. Lopez Bruna, A. L. Roquemore, Federica Bonomo, F. Fantini, Lorenzo Frassinetti, C. Bustreo, Diego Marcuzzi, G. L. Delzanno, Gianluca Spizzo, A. De Lorenzi, Martin, P, Puiatti, M, Agostinetti, P, Agostini, M, Alonso, J, Antoni, V, Apolloni, L, Auriemma, F, Avino, F, Barbalace, A, Barbisan, M, Barbui, T, Barison, S, Barp, M, Baruzzo, M, Bettini, P, Bigi, M, Bilel, R, Boldrin, M, Bolzonella, T, Bonfiglio, D, Bonomo, F, Brombin, M, Buffa, A, Bustreo, C, Canton, A, Cappello, S, Carralero, D, Carraro, L, Cavazzana, R, Chacon, L, Chapman, B, Chitarin, G, Ciaccio, G, Cooper, W, Dal Bello, S, Dalla Palma, M, Delogu, R, De Lorenzi, A, Delzanno, G, De Masi, G, De Muri, M, Dong, J, Escande, D, Fantini, F, Fasoli, A, Fassina, A, Fellin, F, Ferro, A, Fiameni, S, Finn, J, Finotti, C, Fiorentin, A, Fonnesu, N, Framarin, J, Franz, P, Frassinetti, L, Furno, I, Palumbo, M, Gaio, E, Gazza, E, Ghezzi, F, Giudicotti, L, Gnesotto, F, Gobbin, M, Gonzales, W, Grando, L, Guo, S, Hanson, J, Hidalgo, C, Hirano, Y, Hirshman, S, Ide, S, In, Y, Innocente, P, Jackson, G, Kiyama, S, Liu, S, Liu, Y, Lopez Bruna, D, Lorenzini, R, Luce, T, Luchetta, A, Maistrello, A, Manduchi, G, Mansfield, D, Marchiori, G, Marconato, N, Marcuzzi, D, Marrelli, L, Martini, S, Matsunaga, G, Martines, E, Mazzitelli, G, Mccollam, K, Momo, B, Moresco, M, Munaretto, S, Novello, L, Okabayashi, M, Olofsson, E, Paccagnella, R, Pasqualotto, R, Pavei, M, Peruzzo, S, Pesce, A, Pilan, N, Piovan, R, Piovesan, P, Piron, C, Piron, L, Pomaro, N, Predebon, I, Recchia, M, Rigato, V, Rizzolo, A, Roquemore, A, Rostagni, G, Ruzzon, A, Sakakita, H, Sanchez, R, Sarff, J, Sartori, E, Sattin, F, Scaggion, A, Scarin, P, Schneider, W, Serianni, G, Sonato, P, Spada, E, Soppelsa, A, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Takechi, M, Taliercio, C, Terranova, D, Theiler, C, Toigo, V, Trevisan, G, Valente, M, Valisa, M, Veltri, P, Veranda, M, Vianello, N, Villone, F, Wang, Z, White, R, Xu, X, Zaccaria, P, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zollino, G, Zuin, M, and Mazzitelli, G.

Subjects
Nuclear and High Energy Physics, RFX-mod, Tokamak, Strong interaction, reversed field pinch, law.invention, Magnetohydrodynamics, law, RFP, Fusion, Safety factor, Reversed field pinch, Flow transport, Settore FIS/01 - Fisica Sperimentale, Iter tokamak, Fusion power, IAEA Fusion Energy Conference, Science and Technology, Condensed Matter Physics, Active control, Plasma parameter, Plasma devices, Systems engineering, Fusion devices, Magnetic configuration, Stellarator
Abstract

This paper reports the highlights of the RFX-mod fusion science programme since the last 2010 IAEA Fusion Energy Conference. The RFX-mod fusion science programme focused on two main goals: exploring the fusion potential of the reversed field pinch (RFP) magnetic configuration and contributing to the solution of key science and technology problems in the roadmap to ITER. Active control of several plasma parameters has been a key tool in this endeavour. New upgrades on the system for active control of magnetohydrodynamic (MHD) stability are underway and will be presented in this paper. Unique among the existing fusion devices, RFX-mod has been operated both as an RFP and as a tokamak. The latter operation has allowed the exploration of edge safety factor q edge < 2 with active control of MHD stability and studies concerning basic energy and flow transport mechanisms. Strong interaction has continued with the stellarator community in particular on the physics of helical states and on three-dimensional codes. © 2013 IAEA, Vienna.

Published
2013

22. 3D effects on the RFX-mod boundary

Author

Gianluca Spizzo, B. Momo, G. De Masi, M. Spolaore, R. Cavazzana, Silvia Spagnolo, Emilio Martines, Matteo Agostini, Matteo Zuin, Cristina Rea, Paolo Scarin, N. Vianello, Lorella Carraro, Vianello, N, Spizzo, G, Agostini, M, Scarin, P, Carraro, L, Cavazzana, R, De Masi, G, Martines, E, Momo, B, Rea, C, Spagnolo, S, Spolaore, M, and Zuin, M

Subjects
Electric and magnetic measurements, plasma boundary, Physics, Nuclear and High Energy Physics, Fusion, RFX-mod, Ambipolar diffusion, Turbulence, Ripple, Perturbation (astronomy), Atmospheric-pressure plasma, Plasma turbulence, reversed field pinch, Plasma, Mechanics, Condensed Matter Physics, Perturbative methods, Z-pinches plasma focus and other pinch devices, Physics::Plasma Physics, Electric field, RFP, Plasma kinetic equations, Atomic physics
Abstract

In present fusion research a strong effort is devoted to the studies of non-axisymmetric magnetic perturbations and consequent field ergodization on the external region of the plasma. On this topic interesting results can be drawn from the helical configuration observed in high-current regimes in reversed field pinches (RFPs) where the small edge helical ripple is sufficient to modulate the plasma-wall interaction and the plasma kinetic properties. This paper presents the most recent experimental results and physical interpretation of the phenomena observed in the edge region of the RFX-mod RFP device. Experimental observations indicate that plasma pressure and floating potential are spatially modulated according to the helical deformation. Helical flow is observed at the edge as a consequence of an ambipolar electric field. Emphasis will be devoted to the determination of the actual phase relation between magnetic perturbation and velocity perturbation. Evidence of the influence of the helical ripple on turbulence properties at the edge is also reported.

Published
2013

23. The tomographic diagnostic of ITER neutral beam injector

Author

Gianluca Spizzo, Gianluigi Serianni, Roberto Pasqualotto, M. Mattiolo, M. Brombin, Matteo Agostini, and C. Dianin

Subjects
Physics, Nuclear and High Energy Physics, Tomographic reconstruction, business.industry, Pulse duration, Injector, Condensed Matter Physics, Noise (electronics), law.invention, ALGEBRAIC RECONSTRUCTION TECHNIQUE, Simultaneous Algebraic Reconstruction Technique, Optics, RADIOLOGICAL APPLICATIONS, LIMITED-DATA, law, REVERSED-FIELD PINCH, LINE INTEGRALS, Physics::Accelerator Physics, business, Particle beam, Image resolution, Beam (structure)
Abstract

The two-dimensional (2D) density distribution of a particle beam can be reconstructed using a diagnostic based on tomographic techniques, which measures the D? light. This paper presents investigations and tests concerning the reliability of such a diagnostic, applied to the beam produced in MITICA (Megavolt ITER Injector & Concept Advancement) the full-size prototype of the neutral beam injector, which will be used for additional heating on ITER. It aims at developing the technologies to guarantee the correct operation of the injectors to be installed in ITER. The main target of the tomographic diagnostic is the measurement of the beam uniformity with sufficient contrast and spatial resolution, and of its evolution throughout the pulse duration. In particular the ITER beam uniformity is required to be within 10%, thus the error of the tomographic reconstruction has to be lower than this value. The conceptual design of the diagnostic is presented, with a description of the layout and main components. The portholes around the vessel and the geometry of the lines of sight are arranged so as to cover the whole area of the beam. A tomographic algorithm based on the simultaneous algebraic reconstruction technique (SART) is developed to reconstruct the beam intensity profile. Phantoms reproducing different experimental beam configurations are simulated and reconstructed with this technique. The role of noise in the line-integrated signals is studied and its effect on the reconstructed emission is investigated. The unsatisfactory results suggested the introduction of a regularization algorithm, to reduce the effect of the noise in the beam reconstruction. In this way, the simulated phantoms are correctly reconstructed and their 2D spatial non-uniformity is correctly estimated, up to a noise level of 10%.

Published
2013

24. Interplay between edge magnetic topology, pressure profile and blobs in the edge of RFX-mod

Author

Paolo Scarin, Gianluca Spizzo, N. Vianello, Matteo Agostini, and A. Scaggion

Subjects
Physics, Toroid, business.industry, Turbulence, Edge region, DIAGNOSTICS, Condensed Matter Physics, TRANSPORT, Computational physics, FUSION PLASMAS, Optics, Nuclear Energy and Engineering, Mod, TOKAMAK, Spatial ecology, Linear scale, Lagrangian coherent structures, PLASMA TURBULENCE, business, Pressure gradient
Abstract

The observation of the periodic pressure profile time oscillations in the edge region (0.93 < r/a < 1) of a RFX-mod device allows one to investigate the role of pressure as a turbulence regulation mechanism. The proportionality between the radial correlation length of edge fluctuations and the radial characteristic pressure length L-p suggests a sort of regulation of the turbulent spatial scale, where L-p sets the radial dimension of the blobs. Moreover, the spatial scale regulation is confirmed by observing a linear scaling between the energy injection scale and the toroidal dimension of the edge coherent structures. On the other hand, the link between Delta P-e and turbulence level does not hold locally: the edge fluctuation level is higher in the toroidal region of lower edge pressure gradient. Hence if coherent structures are generated locally in the region of strongest Delta P-e, they flow and accumulate where Delta P-e is lower.

Published
2012

25. RFX-mod wall conditioning by lithium pellet injection

Author

S. Fiameni, Stefano Munaretto, David Terranova, Alessandra Canton, Simona Barison, Fulvio Auriemma, Lorella Carraro, G. De Masi, Matteo Agostini, Paolo Scarin, S. Dal Bello, and Paolo Innocente

Subjects
BORONIZATION, Nuclear and High Energy Physics, Materials science, Reversed field pinch, Hydrogen, Magnetic confinement fusion, chemistry.chemical_element, Plasma, Condensed Matter Physics, FUSION PLASMAS, chemistry, REVERSED-FIELD PINCH, TOKAMAK, Particle, RECONSTRUCTION, Lithium, Graphite, Electric current, Composite material
Abstract

Plasma–wall interaction is one of the most important issues that present magnetic confinement devices have to face. In the RFX-mod reversed field pinch experiment plasma–wall interaction has become a hard point increasing plasma current up to the RFX-mod maximum design value of 2 MA, since in this case local power deposition can be as high as 10 MW m−2. Since the first wall of RFX-mod is entirely covered by graphite tiles different techniques have been tested to control hydrogen wall influx: He glow discharges cleaning, He discharges at high plasma currents, wall boronization and baking. With the best results obtained by boronization, at high plasma currents all such techniques improve the situation but do not allow a complete and stationary hydrogen influx reduction. Furthermore, in the presence of localized high power load the wall still responds providing very high influxes. In order to improve this situation wall conditioning by lithium has been tested. As a first lithization method to deposit a controllable amount of lithium on the wall, a room temperature pellet injector has been used (maximum pellet diameter of 1.8 mm and maximum length of 5 mm). Lithium coatings with a theoretical thickness of about 10 nm have been applied both to clean graphite tiles and over boronized ones. Lithization demonstrated to be effective in lowering hydrogen wall recycling to a value smaller than that of boronized graphite, with the effect lasting 20–30% more than in the boronized case. Compared with boronization, lithization slightly improves (by about 30%) particle confinement time and also clearly affects edge particle transport providing a lower edge density and more peaked density profiles. Lithization also reduces carbon content by about 10% over boronization but still no clear improvement has been observed in terms of energy confinement. Similar results have been obtained performing lithization over boronized graphite.

Published
2012

26. Edge turbulence in different density regimes in Alcator C-Mod experiment

Author

Paolo Scarin, Stewart Zweben, Matteo Agostini, and J.L. Terry

Subjects
Physics, Nuclear and High Energy Physics, Tokamak, business.industry, Turbulence, PUFF IMAGING EXPERIMENTS, Flux, SCRAPE-OFF-LAYER, TOKAMAK PLASMA, Plasma, Edge (geometry), Condensed Matter Physics, FLUCTUATION STRUCTURES, Computational physics, law.invention, Optics, Alcator C-Mod, Physics::Plasma Physics, law, INTERMITTENCY, Vector field, Limit (mathematics), business
Abstract

Plasma edge turbulence of Alcator C-Mod tokamak is studied with a fast camera in different density regimes. The statistical properties of the fluctuations, as well as the behaviour of the blobs, are characterized in plasma discharges at different normalized densities, studying the link between the edge turbulence and the Greenwald limit. It is shown that approaching the Greenwald density limit, the edge velocity field measured with the cross-correlation technique changes and the strong fluctuations, which for standard discharges develop mainly outside the separatrix, extend also in the radial region inside the last closed flux surface. At the same time, the blobs cover a larger radial region, suggesting a strong impact of the edge turbulence and transport on the Greenwald limit.

Published
2011

27. Summary of the Workshop on Electric Fields, Turbulence and Self-organization in Magnetized Plasmas (EFTSOMP) 2009: 6–7 July 2009, Sofia, Bulgaria

Author

M. Spolaore, Sergey Soldatov, C. Maszl, C. Hidalgo, Matteo Agostini, E. R. Solano, Alexander Kendl, Peter Lang, Y. Xu, K. McCormick, G. Bonhomme, G. Kocsis, S. Zoletnik, H. W. Müller, Silvia Spagnolo, P. Garcia-Martinez, A.D. Gurchenko, D Dunai, and Eva Belonohy

Subjects
Physics, Self-organization, Nuclear and High Energy Physics, Meteorology, Turbulence, Electric field, Satellite, Plasma, Condensed Matter Physics
Abstract

The Workshop on Electric Fields, Turbulence and Self-organization in Magnetized Plasmas (EFTSOMP) is held annually as a satellite meeting of the EPS Plasma Physics conference. The aim is to foster discussion on the above topic and allow dissemination of recent results and concepts. The paper represents a summary of the talks presented at the conference.

Published
2010

28. Edge turbulence characterization in RFX-mod with optical diagnostics

Author

Paolo Scarin, N. Vianello, Fabio Sattin, R. Cavazzana, M. Spolaore, Matteo Agostini, and G. Serianni

Subjects
Physics, Electron density, Reversed field pinch, business.industry, Turbulence, SCRAPE-OFF-LAYER, Electron, Edge (geometry), ALCATOR C-MOD, Condensed Matter Physics, Molecular physics, PARTICLE-TRANSPORT, Optics, Nuclear Energy and Engineering, Physics::Plasma Physics, REVERSED-FIELD PINCH, Emission spectrum, Phase velocity, business, Pressure gradient, FUSION DEVICES
Abstract

In the edge region of fusion devices coherent structures (blobs) are commonly observed. In order to investigate their evolution and the possible driving mechanisms, we studied the relationship between the size of the coherent structures and the local characteristic length L(p) of the edge electron pressure profile P(e)(r), together with the effect of magnetic fluctuations on del P(e). The results show an increase in the blob size with both Lp and magnetic fluctuations, suggesting an interplay between electron pressure gradient, magnetic fluctuations and edge turbulence generation. Measurements of the spatial scales of the edge turbulence structures and the corresponding toroidal phase velocity are obtained in the reversed field pinch RFX-mod by means of a gas puffing imaging diagnostic, while the local edge profiles of electron density n(e)(r) and temperature T(e)(r) and therefore P(e)(r) have been measured via the line intensity ratio technique of helium emission lines.

Published
2009

29. Fluctuations and power spectra in edge plasmas

Author

Fabio Sattin, J.L. Terry, Matteo Agostini, Paolo Scarin, and Roberto Cavazzana

Subjects
Physics, Turbulence, business.industry, SCRAPE-OFF-LAYER, Plasma, ALCATOR C-MOD, Condensed Matter Physics, Power law, Spectral line, Exponential function, Computational physics, Optics, Nuclear Energy and Engineering, COHERENT STRUCTURES, REVERSED-FIELD PINCH, TURBULENCE, business, Phenomenology (particle physics)
Abstract

The high-frequency range of power spectra of turbulent fluctuating quantities measured at the edge of magnetized plasmas displays a variety of trends: from power laws with different spectral indices to exponential. We propose a model able to account for the whole phenomenology simply by tuning the distribution in the duration of the signal spikes. Comparisons with data from RFX-mod and Alcator C-Mod experiments are performed. An attempt to relate the statistics of the bursts with their generating mechanism is made.

Published
2009

30. High density physics in reversed field pinches: comparison with tokamaks and stellarators

Author

E. Gazza, M. E. Puiatti, F. Sattin, Rita Lorenzini, Paolo Innocente, Italo Predebon, Gianluca Spizzo, Paolo Scarin, S. Dal Bello, Roberto Paccagnella, M. Valisa, Alessandra Canton, D. Terranova, L. Marrelli, D. Bonfiglio, Lorella Carraro, Susanna Cappello, Roberto Cavazzana, P. Piovesan, Alberto Alfier, Matteo Agostini, R. Piovan, and Paolo Zanca

Subjects
Physics, Nuclear and High Energy Physics, Electron density, RFX-MOD, W7-AS STELLARATOR, Tokamak, Condensed matter physics, Turbulence, Magnetic confinement fusion, CONFINEMENT, Plasma, Condensed Matter Physics, LIMIT, law.invention, Computational physics, PARTICLE-TRANSPORT, Physics::Plasma Physics, law, Physics::Space Physics, Radiative transfer, Magnetohydrodynamics, Stellarator
Abstract

Reversed field pinches (RFPs) share with tokamaks and stellarators the experimental evidence of an upper limit for the maximum value of the electron density at which they can operate. Above a certain density level, well described by the Greenwald law for tokamaks and RFPs, a radiative collapse with strong plasma cooling is observed, predominantly due to processes occurring at the plasma boundary. In the RFX-mod RFP close to the density limit a radiating belt, poloidally symmetric and toroidally localized, develops in the region where the plasma is shrunk as an effect of the m = 0 tearing modes. The phenomenology recalls that of MARFES or plasma detachment, though, unlike tokamaks, the appearance of the radiating belt is associated with a soft landing of the plasma discharge. The paper reports the experimental pattern of the RFX-mod plasmas close to the density limit, including density and radiation profiles, plasma flow and turbulence. Particles are toroidally conveyed towards the region of maximum shrinking of the plasma column where they accumulate. The interpretation is related to the topology of MHD m = 0 and m = 1 modes: the reconstruction of the magnetic topology shows that the highly radiating region corresponds to the presence of peripheral m = 0 magnetic islands well detached from the wall. The emerging indication is that in RFPs a reduction of the m = 0 activity could be a way to overcome the density limit.

Published
2009

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