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1. Overview of the FTU results

Author

G. Pucella, E. Alessi, S. Almaviva, B. Angelini, M.L. Apicella, G. Apruzzese, M. Aquilini, G. Artaserse, B. Baiocchi, M. Baruzzo, F. Belli, W. Bin, F. Bombarda, L. Boncagni, S. Briguglio, A. Bruschi, P. Buratti, G. Calabrò, M. Cappelli, A. Cardinali, N. Carlevaro, D. Carnevale, L. Carraro, C. Castaldo, F. Causa, R. Cavazzana, S. Ceccuzzi, P. Cefali, C. Centioli, R. Cesario, S. Cesaroni, C. Cianfarani, M. Ciotti, G. Claps, F. Cordella, F. Crisanti, Y. Damizia, O. D’Arcangelo, M. De Angeli, E. Di Ferdinando, S. Di Giovenale, C. Di Troia, A. Dodaro, B. Esposito, M. Falessi, F. Fanale, D. Farina, L. Figini, G. Fogaccia, D. Frigione, V. Fusco, L. Gabellieri, G. Gallerano, S. Garavaglia, G. Ghillardi, G. Giacomi, E. Giovannozzi, G. Gittini, G. Granucci, G. Grosso, L.A. Grosso, M. Iafrati, L. Laguardia, E. Lazzaro, D. Liuzza, M. Lontano, G. Maddaluno, S. Magagnino, M. Marinucci, D. Marocco, G. Mazzitelli, C. Mazzotta, C. Meineri, V. Mellera, M. Mezzacappa, A. Milovanov, D. Minelli, F.C. Mirizzi, G. Montani, A. Moro, F. Napoli, S. Nowak, F.P. Orsitto, D. Pacella, F. Pallotta, S. Palomba, L. Panaccione, A. Pensa, V. Pericoli-Ridolfini, P. Petrolini, V. Piergotti, C. Piron, A. Pizzuto, S. Podda, M.E. Puiatti, G. Ramogida, B. Raspante, G. Ravera, D. Ricci, N. Rispoli, G. Rocchi, A. Romano, G. Rubino, S. Rueca, M. Scisciò, L. Senni, A. Sibio, A. Simonetto, C. Sozzi, U. Tartari, A. Taschin, B. Tilia, G. Trentuno, A.A. Tuccillo, O. Tudisco, R. Tulli, M. Valisa, M. Vellucci, B. Viola, E. Vitale, G. Vlad, D. Zannetti, B. Zaniol, M. Zerbini, F. Zonca, V.K. Zotta, M. Angelone, C. Barcellona, L. Calacci, L. Caneve, F. Colao, B. Coppi, S. Galeani, C. Galperti, P. Gasior, W. Gromelski, M. Hoppe, M. Kubkowska, V. Lazic, M. Lehnen, M. Marinelli, F. Martinelli, E. Milani, P. Mosetti, P. Muscente, E. Nardon, M. Passeri, A. Reale, M. Sassano, A. Selce, C. Verona, and G. Verona-Rinati

Subjects
Settore FIS/01, Nuclear and High Energy Physics, Physics::Plasma Physics, overview, FTU, FEC, Physics::Space Physics, spectrometer, system, Condensed Matter Physics, equipment and supplies, tokamak
Abstract

Since the 2018 IAEA FEC Conference, FTU operations have been devoted to several experiments covering a large range of topics, from the investigation of the behaviour of a liquid tin limiter to the runaway electrons mitigation and control and to the stabilization of tearing modes by electron cyclotron heating and by pellet injection. Other experiments have involved the spectroscopy of heavy metal ions, the electron density peaking in helium doped plasmas, the electron cyclotron assisted start-up and the electron temperature measurements in high temperature plasmas. The effectiveness of the laser induced breakdown spectroscopy system has been demonstrated and the new capabilities of the runaway electron imaging spectrometry system for in-flight runaways studies have been explored. Finally, a high resolution saddle coil array for MHD analysis and UV and SXR diamond detectors have been successfully tested on different plasma scenarios.

Published
2022

2. High density internal transport barriers for burning plasma operation

Author

Gian Luca Ravera, B. Angelini, Maria Ester Puiatti, F. Crisanti, Fulvio Zonca, G. Apruzzese, Alessandro Bruschi, D. Pacella, G.B. Righetti, M. Leigheb, D. Frigione, S. Nowak, B. Tilia, Gregorio Vlad, F. De Marco, Francesco Mirizzi, F. P. Orsitto, G. Calabrò, S. Podda, C. Gormezano, H. Kroegler, V. Cocilovo, S V Annibaldi, A. Bertocchi, L. Pieroni, E. Lazzaro, E. Giovannozzi, R. Cesario, Alessandro Simonetto, Angelo A. Tuccillo, Francesco Romanelli, G Monari, Lorella Carraro, Gustavo Granucci, E. Barbato, D Marocco, M.L. Apicella, C. Centioli, S. Cirant, M. De Benedetti, V. Vitale, C. Castaldo, P. Buratti, L. Gabellieri, G. Mazzitelli, Basilio Esposito, L. Panaccione, V. Pericoli Ridolfini, G. Maddaluno, M. Romanelli, F. Gandini, A. Cardinali, F. Iannone, M. Marinucci, M. Panella, P. Smeulders, E. Sternini, G Regnoli, Carlo Sozzi, R. De Angelis, C. Mazzotta, and O. Tudisco

Subjects
Tokamak, Materials science, TOKAMAKS, Cyclotron, Magnetic confinement fusion, CONFINEMENT, Plasma, Electron, Condensed Matter Physics, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Bootstrap current, law.invention, Nuclear Energy and Engineering, law, ITER, Plasma diagnostics, FTU, Atomic physics, Ohmic contact, CURRENT DRIVE
Abstract

A tokamak plasma with internal transport barriers (ITBs) is the best candidate for a steady ITER operation, since the high energy confinement allows working at plasma currents (Ip) lower than the reference scenario. To build and sustain an ITB at the ITER high density (>=1020 m-3) and largely dominant electron (e-) heating is not trivial in most existing tokamaks. FTU can instead meet both requests, thanks to its radiofrequency heating systems, lower hybrid (LH, up to 1.9 MW) and electron cyclotron (EC up to 1.2 MW). By the combined use of them, ITBs are obtained up to peak densities ne0 > 1.3 × 1020 m-3, with central e- temperatures Te0 ? 5.5 keV, and are sustained for as long as the heating pulse is applied (>35 confinement times, ?E). At ne0 ? 0.8 × 1020 m-3 Te0 can be larger than 11 keV. Almost full current drive (CD) and an overall good steadiness is attained within about one ?E, 20 times faster than the ohmic current relaxation time. The ITB extends over a central region with an almost flat or slightly reversed q profile and qmin ? 1.3 that is fully sustained by off-axis lower hybrid current drive. Consequent to this is the beneficial good alignment of the bootstrap current, generated by the ITB large pressure gradients, with the LH driven current. Reflectometry shows a clear change in the turbulence close to the ITB radius, consistent with the reduced e- transport. Ions (i+) are significantly heated via collisions, but thermal equilibrium with electrons cannot be attained since the e--i+ equipartition time is always 4-5 times longer than ?E. No degradation of the overall ion transport, rather a reduction of the i+ heat diffusivity, is observed inside the ITB. The global confinement has been improved up to 1.6 times over the scaling predictions. The ITB radius can be controlled by adjusting the LH power deposition profile that is affected mostly by the q value of the discharge, while the ITB strength can be varied through central EC heating. FTU experiments have shown that ITER-like e-ITBs are achievable.

Published
2005

3. Chapter 10: FTU Operation

Author

B. Angelini, V. Vitale, Cristina Centioli, G. Buceti, F. Iannone, M.L. Apicella, F. Crisanti, M. Panella, G. Mazza, and G. Mazzitelli

Subjects
Nuclear and High Energy Physics, Tokamak, Computer science, 020209 energy, Mechanical Engineering, Nuclear engineering, Frascati Tokamak Upgrade, Magnetic confinement fusion, 02 engineering and technology, Plasma, 01 natural sciences, 010305 fluids & plasmas, law.invention, Reliability (semiconductor), Data acquisition, Nuclear magnetic resonance, Open source, Nuclear Energy and Engineering, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Plasma diagnostics, Civil and Structural Engineering
Abstract

Some specific points of the Frascati Tokamak Upgrade (FTU) operation are presented for plasma performance as well as for the machine availability and the development of new tools needed to operate in a complex scenario needed for tokamak research. The different techniques adopted for wall conditioning of the FTU are reviewed. Plasmas with low Z{sub eff} have been achieved including those at low density and high additional heating power. The obtained experimental results are discussed in terms of better operation and plasma performance achieved. As with any other large - and thus long-lasting - experiments, a mixture of old and new technological solutions inserted in an open source framework characterizes the FTU data control and acquisition systems. We give some information on the original architecture and try to detail its current state. The high level of reliability presently achieved is discussed.

Published
2004

4. Steady improved confinement in FTU high field plasmas sustained by deep pellet injection

Author

B. Angelini, C. Castaldo, E. Giovannozzi, D. Frigione, C. Gormezano, H. Kroegler, V. Vershkov, L. Garzotti, Paolo E. Trevisanutto, R. Cesario, Francesca Poli, F. Crisanti, Giovanni Bracco, O. Tudisco, Fulvio Zonca, V. Cocilovo, A. Bertocchi, P. Chuilon, G. Apruzzese, Francesco Mirizzi, M. Leigheb, L. Pieroni, F. De Marco, L. Panaccione, P. Smeulders, A.A. Petrov, M. De Benedetti, B. Esposito, L. Gabellieri, S. E. Segre, G. Pulcella, M. Marinucci, Francesco Romanelli, E. Barbato, M.L. Apicella, S. Cascino, A. A. Tuccillo, Luciano Bertalot, G. Maffia, M. Zerbini, F. Alladio, G. Maddaluno, P. Buratti, F. Iannone, G.B. Righetti, F. Santini, E. Stermini, Gregorio Vlad, M. Romanelli, G. Buceti, M. Grolli, Cristina Centioli, G. Mazzitelli, M. Sassi, Giancarlo Gatti, P. Micozzi, A. Cardinali, F. Gravanti, G. L. Ravera, N. Tartoni, R. De Angelis, B. Tilia, M. Panella, V. Zanza, V. Vitale, V. Pericoli-Ridolfini, D. Pacella, Salvatore Podda, and P. Papitto

Subjects
Coupling, Nuclear and High Energy Physics, Materials science, Toroidal field, Plasma, Alpha particle, Condensed Matter Physics, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Core (optical fiber), Physics::Plasma Physics, Pellet, Neutron, High field, Atomic physics
Abstract

High density plasmas (n0 ≈ 8 × 1020m-3) featuring steady improved core confinement have been obtained in FTU up to the maximum nominal toroidal field (8 T) by deep multiple pellet injection. These plasmas also feature high purity efficient electron-ion coupling and peaked density profiles sustained for several confinement times. Neutron yields in excess of 1 × 1013 n/s are measured, consistent with the reduction of the ion transport to neoclassical levels.

Published
2001

5. Frascati tokamak upgrade recent results and future programme

Author

D. Frigione, F. Crisanti, F. Gravanti, R. Cesario, V. Cocilovo, Francesco Romanelli, V. Pericoli, A Buceti, P. Chuilon, B. Angelini, Angelo A. Tuccillo, V. Vitale, M. Panella, S. Ciattaglia, E. Sternini, F Maddaluno, G. Mazzitelli, and S Cirant

Subjects
Tokamak, Mechanical Engineering, Nuclear engineering, Frascati Tokamak Upgrade, Fusion power, Nuclear reactor, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), law.invention, Nuclear physics, Nuclear Energy and Engineering, law, Environmental science, General Materials Science, Civil and Structural Engineering
Abstract

A general overview of the Frascati tokamak upgrade (FTU) machine for the period 1997–1999 is given. The status of the major systems and the relevant upgrades are discussed together with some data on the operating experience, the main scientific results and the near term programme.

Published
2000

6. High Core Electron Confinement Regimes in FTU Plasmas with Low- or Reversed-Magnetic Shear and High Power Density Electron-Cyclotron-Resonance Heating

Author

H. Kroegler, F. Alladio, M. Leigheb, E. Giovannozzi, P. Buratti, Francesco Romanelli, Gregorio Vlad, O. Tudisco, F.P. Orsitto, G. Buceti, B. Esposito, L. Acitelli, M. Zerbini, F. Crisanti, Fulvio Zonca, M.L. Apicella, S. Nowak, G. Mazzitelli, E. Barbato, V. Cocilovo, F. Santini, Carlo Sozzi, S. Cirant, L. Pieroni, V. Vitale, F. De Marco, Luciano Bertalot, R. De Angelis, G. Maddaluno, M. Sassi, V. Zanza, L. Panaccione, D. Pacella, Gustavo Granucci, Francesco Mirizzi, V. Pericoli Ridolfini, S. Ciattaglia, M. Panella, C. Cianfarani, L. Gabellieri, M. Marinucci, M. Borra, Alessandro Simonetto, C. Gourlan, Giancarlo Gatti, A. Cardinali, G. Maffia, Giovanni Bracco, G.B. Righetti, A. A. Tuccillo, G. Apruzzese, R. Cesario, M. Grolli, Cristina Centioli, S. Sternini, Salvatore Podda, B. Angelini, P. Micozzi, A. Bertocchi, Alessandro Bruschi, A. Imparato, S. E. Segre, L. Lovisetto, and D. Frigione

Subjects
Physics, General Physics and Astronomy, Plasma, Electron, Thermal diffusivity, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Electron cyclotron resonance, Ion, Shear (sheet metal), ___, Core electron, Physics::Plasma Physics, Atomic physics, Ohmic contact
Abstract

Electron temperatures in excess of 8 keV have been obtained by electron-cyclotron-resonance heating on FTU plasmas at peak densities up to $8\ifmmode\times\else\texttimes\fi{}{10}^{19}\mathrm{m}{}^{\ensuremath{-}3}$. The magnetic shear in the plasma core is low or negative, and the electron heat diffusivity remains at, or below, the Ohmic level $(0.2\mathrm{m}{}^{2}/\mathrm{s})$, in spite of the very large heating power density $(10--20\mathrm{MW}/\mathrm{m}{}^{3})$ which produces extremely high temperature gradients (up to 120 keV/m). The ion heat transport remains at the neoclassical level.

Published
1999

7. Multilingual person to person communication at IRST

Author

Daniele Falavigna, Mauro Cettolo, B. Angelini, Anna Corazza, G. Lazzari, B., Angelini, M., Cettolo, Corazza, Anna, D., Falavigna, and G., Lazzari

Subjects
Deep linguistic processing, Computer science, business.industry, Speech synthesis, Artificial intelligence, Computational linguistics, business, computer.software_genre, Speech processing, computer, Natural language, Natural language processing, Spoken language
Abstract

This paper refers to a machine-mediated person-to-person multilingual communication system. Stress is put on robustness, that is the ability of the system to preserve communication even in presence of the variability and errors typical of spoken language systems. The statistical approach is adopted not only at the acoustic level, but also for the linguistic processing. Therefore, while an overview of the global architecture is briefly introduced, the focus is put on the acoustic recognizer and the understanding module. Experimental evaluations complete the presentation.

Published
2002

8. Abstracts of papers and posters advanced activities in pharmaceutical care 24th European Symposium on Clinical Pharmacy

Author

M. C. Nahata, J. L. Bootman, Z. Zadák, P. B. Soeters, Laurence A. Goldberg, S. Stremetzne, U. Jaehde, M. Streit, E. D. Kreuser, E. Thiel, W. Schunack, R. T. Calvert, M. Feely, H. Chrystyn, M. A. Mangues, G. Ginovart, M. A. Moral, A. P. Lopes, R. Farré, X. Demestre, O. Altirriba, Ch. Kloft, J. Beyer, J. Steuer, W. Siegert, J. Bever, M. Bialer, S. Sussan, O. Abu Salach, H. D. Danenberg, A. Laor, M. I. Barnett, A. G. Cosslett, J. Cohen, P. Marini, C. Bassi, A. Bonzanini, T. Cassani, G. Ore, G. Mangiante, G. Scroccaro, M. Kaczan, J. Eriksen, B. Toft, M. Jandová, J. Vlček, V. Klemerová, L. Sobotka, A. Ayestarán, R. López, J. B. Montoro, L. Pou, A. Estíbalez, B. Pascual, M. D. Aumente, M. D. Panadero, M. Caraballo, J. C. Pozo, J. L. Perez, A. C. Falcão, M. M. Fernández de Gatta, A. Dominguez-Gil, M. M. Caramona, J. M. Lanao, Z. Fendrich, J. Zajic, Medall M. D. Bellés, Alós V. G. Casabó, Torres N. V. Jiménez, Botella M. A. Hervás, Gimeno F. J. Abad, Melchor D. E. Casterá, M. Aminian, A. Clopés, C. Branco, I. Badell, N. Pardo, C. Palací, J. Bonal, G. Rialp, B. Bara, M. Nobilis, V. Bláha, E. Havel, J. Květina, M. Brátová, D. Solichová, M. Mullerova, D. Svoboda, M. Pokrajac, B. Miljković, D. Simić, B. Brzaković, A. Galetin, R. L. Pinheiro, A. P. Carrondo, E. Sieradzki, K. Strauss, E. Olejarz, A. Marzec, J. Kaużny, J. Szymura-Oleksiak, E. Wyska, B. Jarosz, I. Kosowicz, K. Fabirkiewicz, R. Cherian, A. -L. Vodoz, B. Imsand, D. Belli, Th. Rochat, H. Müllerová, F. Falcão, A. Carvalho, T. Pereira, C. Fonseca, O. Freitas, M. Resende, A. Parrinha, M. Costa, M. A. Pessanha, A. Ferreira, L. Mourão, F. Ceia, Mendonça Lima, R. Tavares, A. SalesLuis, Santos Carlos, M. E. Araújo Pereira, J. Alves do Carmo, J. M. Forjaz Lacerda, J. A. Morais, C. Beaufils, M. Duff, P. Zamparutti, P. Assicot, M. Bohor, B. Angelini, M. Lambert, J. C. Manelli, A. Gayte-Sorbier, M. C. Bongrand, P. Timon-David, I. C. Fiqueira, R. Lourenco, P. A. Silva, M. O. Rodrigues, A. Fischer, W. Schorr, R. Radziwill, M. Lihtamo, A. Jäppinen, K. Tuovinen, M. Pekkala, L. Nuutinen, L. Morató, L. Lorente, J. Muñoz, Ph Monges, A. Blancard, B. Lacarelle, J. P. Denis, M. -C. Bongrand, Ch Penot-Ragon, F. Gouin, Nicole Petitcollot, I. Tinguely, J. Beney, S. Marty, J. -Ph. Reymond, J. Bussels, H. Robays, A. Litzinger, R. Rohda-Bohler, M. S. Salek, S. Turpin, E. Derby, B. Millar, C. Maggs, L. M. Santiago, Marques Batel, G. Cajaraville, M. J. Tarnés, M. J. Díaz, C. Pozo, A. Plazaola, M. Vuelta, E. Díaz-Munío, A. Ferrer, A. Lozano, R. Guerra, J. L. Pontón, K. Kint, A. Verstraetep, D. El Eini, R. K. Ojala, K. M. Kontra, T. J. P. Naaranlahti, M. Martorell, M. Oliveras, C. Juste, M. T. Lopez, E. Hidalgo, M. J. Cabañas, C. Barroso, J. M. Llop, M. Rey, E. Diaz-Munio, L. Pastó, M. Tubau, M. J. Gómez-Bellver, J. Rodriguez, J. M. Gómez, M. L. Gónzalez, V. Gol, V. Fuentes, S. Ramón, L. Girona, T. Castelló, M. Olona, L. García, C. Girón, C. Monteserín, P. Gonzalez, C. Alberola, J. A. L. Feio, D. Pharm, F. J. Batel Marques, Alexandrino M. Borges, S. Salek, M. C. Escoms, I. Caro, N. Ticó, M. Hidalgo, R. Bruguera, R. Jodar, J. M. Dowell, P. G. Davey, M. Malek, M. Rev, I. Ferrer, T. Marti, M. Ibars, J. P. Delporte, M. Ansseau, A. Albert, M. Sibourg, O. Gaspard, M. Deprez, H. M. Ndougsa, M. Poma, M. J. Tamés, K. Macek, M. Klejna, S. Dhillon, I. Castro, M. Newton, I. A. Zupanets, V. P. Chernyh, N. B. Bezdetko, S. B. Popov, M. N. Velieva, S. M. Babajeya, Y. D. Mamedov, Y. Dj. Mammedov, P. M. Veliev, A. A. Nasudari, A. A. Bandalieva, S. Nordbo, M. Smith-Solbakken, R. Myklctun, W. Berge, M. Thormodsen, L. A. Zupanets, L. S. Kicenko, S. I. Plusch, S. G. Isaev, L. Vokrouhlický, R. Souček, P. Kuneš, O. Nývlt, L. A. Potselueva, S. N. Egorova, E. A. Kadirova, L. E. Ziganshina, J. Chaloupka, and K. Genger

Subjects
Pharmacology, medicine.medical_specialty, business.industry, Alternative medicine, Pharmaceutical Science, Pharmacy, General Medicine, Toxicology, Pharmaceutical Care, 030226 pharmacology & pharmacy, Article, Clinical pharmacy, 03 medical and health sciences, 0302 clinical medicine, Pharmaceutical care, Family medicine, European Symposium, medicine, Internal Medicine, Clinical Pharmacy, Pharmacology (medical), 030212 general & internal medicine, Public Health, business
Published
1995

9. Overview of FTU results

Author

L. Gabellieri, G. Monari, H. Kroegler, V. Fusco, Gian Luca Ravera, L. Amicucci, M. Vellucci, C. Mazzotta, Francesco Mirizzi, M. Aquilini, E. Barbato, R. Coletti, G. Grosso, A. Bertocchi, G. Ramogida, D. Pacella, Zwinglio Guimarães-Filho, B. Angelini, E. Giovannozzi, E. Sternini, R. Tulli, E. Vitale, C. Torelli, M.L. Apicella, M. De Angeli, A. Grosso, B. Tilia, M. Mezzacappa, Giovanni Grossetti, D. Frigione, A. Milovanov, S. Nowak, C. Castaldo, F. Gravanti, A. Moro, C. Centioli, O. D'Arcangelo, F. De Luca, I. Chavdarovski, D. Zannetti, F. P. Orsitto, Daniele Marocco, Sergio Briguglio, A. Cardinali, S. Cirant, C. Di Troia, L. Garzotti, A. Romano, O. Tudisco, P. Cefali, Gustavo Granucci, G. Bracco, A. Jacchia, E. Lazzaro, M. Zerbini, G. Fogaccia, M. Lontano, V. Piergotti, G. Calabrò, S. Podda, V. Pericoli-Ridolfini, X. Wang, G. Breyannis, Alessandro Biancalani, Francesco Pegoraro, V. Muzzini, Luca Boncagni, Liu Chen, Aldo Pizzuto, E. Di Ferdinando, G. Maddaluno, M. Romanelli, F. Belli, P. Petrolini, Alessandro Bruschi, G. Apruzzese, A. Garavaglia, Gabor Szepesi, M. Marinucci, Andreas Bierwage, C. Cianfarani, F. Iannone, G. Rocchi, A. Botrugno, A. Sibio, Carlo Sozzi, G. Ramponi, A. Pensa, B. Raspante, R. De Angelis, F. Crisanti, William Bin, Fulvio Zonca, Angelo A. Tuccillo, Silvio Ceccuzzi, G. Mazzitelli, L. Di Matteo, G. Pucella, S. Di Giovenale, V Zanza, P. Buratti, Basilio Esposito, Gregorio Vlad, M. Panella, L. Panaccione, G. Giacomi, V. Mellera, and R. Cesario

Subjects
Nuclear and High Energy Physics, Materials science, Cyclotron, Electron, Plasma, Collisionality, Condensed Matter Physics, Electron cyclotron resonance, law.invention, Computational physics, Nuclear magnetic resonance, Physics::Plasma Physics, law, FTU results, Limiter, Pinch, Magnetohydrodynamics
Abstract

New FTU ohmic discharges with a liquid lithium limiter at I P = 0.7–0.75 MA, B T = 7 T and n e0 ⩾ 5 × 1020 m−3 confirm the spontaneous transition to an enhanced confinement regime, 1.3–1.4 times ITER-97-L, when the density peaking factor is above a threshold value of 1.7–1.8. The improved confinement derives from a reduction of electron thermal conductivity (χe) as density increases, while ion thermal conductivity (χi) remains close to neoclassical values. Linear microstability reveals the importance of lithium in triggering a turbulent inward flux for electrons and deuterium by changing the growth rates and phase of the ion-driven turbulence, while lithium flux is always directed outwards. A particle diffusion coefficient, D ∼ 0.07 m2 s−1, and an inward pinch velocity, V ∼ 0.27 m s−1, in qualitative agreement with Bohm–gyro-Bohm predictions are inferred in pellet fuelled lithized discharges. Radio frequency heated plasmas benefit from cleaner plasmas with edge optimized conditions. Lower hybrid waves penetration and current drive effects are clearly demonstrated at and above ITER densities thanks to a good control of edge parameters obtained by plasma operations with the external poloidal limiter, lithized walls and pellet fuelling. The electron cyclotron (EC) heating system is extensively exploited in FTU for contributing to ITER-relevant issues such as MHD control: sawtooth crash is actively controlled and density limit disruptions are avoided by central and off-axis deposition of 0.3 MW of EC power at 140 GHz. Fourier analysis shows that the density drop and the temperature rise, stimulated by modulated EC power in low collisionality plasmas are synchronous, implying that the heating method is the common cause of both the electron heating and the density drop. Perpendicularly injected electron cyclotron resonance heating is demonstrated to be more efficient than the obliquely injected one, reducing the minimum electric field required at breakdown by a factor of 3. Theoretical activity further develops the model to interpret high-frequency fishbones on FTU and other experiments as well as to characterize beta-induced Alfvén eigenmodes induced by magnetic islands in ohmic discharges. The theoretical framework of the general fishbone-like dispersion relation is used for implementing an extended version of the HMGC hybrid MHD gyrokinetic code. The upgraded version of HMGC will be able to handle fully compressible non-linear gyrokinetic equations and 3D MHD.

Published
2011

10. Current drive at plasma densities required for thermonuclear reactors

Author

G. Maddaluno, S. Novak, E. Vitale, V. Zanza, E. Giovannozzi, G. Apruzzese, G. Pucella, L. Di Matteo, M. Zerbini, William Bin, B. Angelini, Silvio Ceccuzzi, G. Mazzitelli, P. Micozzi, Gustavo Granucci, Gregorio Vlad, F. Crisanti, L. Gabellieri, S. Cirant, B. Esposito, G. Monari, A. Moro, V. Fusco, G. Calabrò, F.P. Orsitto, Giovanni Grosso, Cristina Centioli, A. Garavaglia, L. Panaccione, C. Di Troia, Luca Boncagni, G. Belli, Alessandro Bruschi, Francesco Mirizzi, E. Sternini, Giuseppe Schettini, M. Marinucci, A. Milovanov, C. Mazzotta, A. Botrugno, O. Tudisco, Giovanni Grossetti, Sergio Briguglio, C. Cianfarani, G. Fogaccia, V. Pericoli, C. Castaldo, A. A. Tuccillo, R. Cesario, Fulvio Zonca, Ocleto D'Arcangelo, E. Barbato, F. Santini, F. Iannone, M.L. Apicella, A. Cardinali, L. Amicucci, D. Frigione, M. Panella, G. L. Ravera, Daniele Marocco, Alessandro Galli, R. De Angelis, Cesario, R, Amicucci, L, Cardinali, A, Castaldo, C, Marinucci, M, Panaccione, L, Santini, F, Tudisco, O, Apicella, Ml, Calabro, G, Cianfarani, C, Frigione, D, Galli, A, Mazzitelli, G, Mazzotta, C, Pericoli, V, Schettini, Giuseppe, and Tuccillo, Aa

Subjects
Multidisciplinary, Materials science, Tokamak, Thermonuclear fusion, Nuclear engineering, General Physics and Astronomy, General Chemistry, Plasma, General Biochemistry, Genetics and Molecular Biology, law.invention, Nuclear physics, Core (optical fiber), ___, Physics::Plasma Physics, law, Physics::Space Physics, Nuclear fusion, Radio frequency, Current (fluid), lower-hybrid waves, plasma heating, thermonuclear reactors
Abstract

Progress in thermonuclear fusion energy research based on deuterium plasmas magnetically confined in toroidal tokamak devices requires the development of efficient current drive methods. Previous experiments have shown that plasma current can be driven effectively by externally launched radio frequency power coupled to lower hybrid plasma waves. However, at the high plasma densities required for fusion power plants, the coupled radio frequency power does not penetrate into the plasma core, possibly because of strong wave interactions with the plasma edge. Here we show experiments performed on FTU (Frascati Tokamak Upgrade) based on theoretical predictions that nonlinear interactions diminish when the peripheral plasma electron temperature is high, allowing significant wave penetration at high density. The results show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.

Published
2010

11. Overview of the FTU results

Author

B. Tilia, D. Frigione, G. Maddaluno, David N. Wagner, C. Cianfarani, F. Belli, A. Grosso, Cristina Centioli, Mario Cavinato, V. Fusco, L. Panaccione, F. Colao, A. A. Tuccillo, E. Di Ferdinando, L. Jakubowski, M. Aquilini, Francesco Mirizzi, A. Milovanov, Sergio Briguglio, Gustavo Granucci, G. Ramogida, G. Calabrò, E. Giovannozzi, G. Pucella, Saul Garavaglia, D. Pacella, A. Pensa, D. Marocco, B. Angelini, L. Amicucci, Daniele Carnevale, M. De Angeli, V. Piergotti, F. Crescenzi, R. Tulli, A. Moro, A.V. Vertkov, A. Sibio, Karol Malinowski, Francesco Maviglia, D. Minelli, S. Nowak, Ocleto D'Arcangelo, B. Viola, Gregorio Vlad, Luca Boncagni, M. Lontano, G. L. Ravera, Duccio Testa, I.E. Lyublinski, C. Castaldo, E. Alessi, C. Di Troia, Marek J. Sadowski, M. Vellucci, J. Zebrowski, A. Bertocchi, G. Apruzzese, S. Almaviva, P. Petrolini, D. Ricci, Marco Riva, Daniela Farina, William Bin, Salvatore Podda, Carlo Sozzi, Jose Ramon Martin-Solis, A. Romano, B. Raspante, E. Lazzaro, M. Reale, F. Iannone, M. Marinucci, C. Mazzotta, R. De Angelis, Z. Popovic, A. Botrugno, M. Mosconi, J. X. Rossel, G. P. Canal, L. Federspiel, E. Vitale, D. Zannetti, C. Marchetto, M. Rabinski, A. Cardinali, Cristian Galperti, F. Orsitto, S. Di Giovenale, Luisa Caneve, G. Fogaccia, M. Zerbini, Giovanni Grosso, V. Cocilovo, Silvio Ceccuzzi, F. Crisanti, F. Causa, G. Mazzitelli, H. Reimerdes, R. Fantoni, M. Mezzacappa, Alessandro Bruschi, A. Pizzuto, M. Panella, E. Barbato, P. Cefali, G. Rocchi, B. Esposito, Mario Sassano, Sergio Galeani, G. Artaserse, Lorenzo Figini, Olivier Sauter, L. Gabellieri, O. Tudisco, R. Cesario, S. Roccella, A. N. Karpushov, V. Zanza, S. Cirant, B. P. Duval, V. Pericoli-Ridolfini, G. Giacomi, D. Kim, P. Buratti, V. Mellera, M.L. Apicella, Fulvio Zonca, Roccella, S., Riva, M., Reale, M., Fantoni, R., Crescenzi, F., Colao, F., Almaviva, S., Zannetti, D., Vellucci, M., Tulli, R., Tilia, B., Sibio, A., Rocchi, G., Raspante, B., Piergotti, V., Petrolini, P., Pensa, A., Mezzacappa, M., Grosso, A., Giacomi, G., Di Giovenale, S., Di Ferdinando, E., Cefali, P., Aquilini, M., Zonca, F., Zerbini, M., Zanza, V., Vlad, G., Vitale, E., Viola, B., Tudisco, O., Tuccillo, A. A., Romano, A., Ravera, G., Ramogida, G., Podda, S., Pizzuto, A., Panella, M., Pacella, D., Orsitto, F. P., Milovanov, A., Mazzotta, C., Mazzitelli, G., Marocco, D., Marinucci, M., Maddaluno, G., Iannone, F., Giovannozzi, E., Gabellieri, L., Fusco, V., Frigione, D., Fogaccia, G., Esposito, B., Di Troia, C., De Angelis, R., D'Arcangelo, O., Crisanti, F., Cocilovo, V., Cianfarani, C., Cesario, R., Centioli, C., Ceccuzzi, S., Causa, F., Castaldo, C., Cardinali, A., Calabró, G., Buratti, P., Briguglio, S., Botrugno, A., Boncagni, L., Bertocchi, A., Belli, F., Barbato, E., Artaserse, G., Apruzzese, G., Apicella, M. L., Angelini, B., Amicucci, L., and Pucella, G.

Subjects
FRASCATI TOKAMAK UPGRADE, Nuclear and High Energy Physics, Tokamak, Materials science, Nuclear engineering, Cyclotron, overview, CYCLOTRON CURRENT DRIVE, law.invention, Settore FIS/04 - Fisica Nucleare e Subnucleare, symbols.namesake, law, Physics::Plasma Physics, Limiter, Langmuir probe, CURRENT-DRIVE, tokamak, Magnetic confinement fusion, IMPROVED CONFINEMENT, Plasma, Condensed Matter Physics, PELLET INJECTION, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), TRANSPORT, LITHIUM LIMITER, PLASMAS, TOKAMAK, MODE, CONFINEMENT, FTU, INTERNAL TRANSPORT BARRIERS, ___, JOINT EUROPEAN TORUS, ____, symbols, CURRENT DRIVE EXPERIMENTS, LOWER-HYBRID WAVES, Plasma diagnostics, Electric current, Atomic physics
Abstract

Since the 2012 IAEA-FEC Conference, FTU operations have been largely devoted to runaway electrons generation and control, to the exploitation of the 140GHz electron cyclotron (EC) system and to liquid metal limiter elements. Experiments on runaway electrons have shown that the measured threshold electric field for their generation is larger than predicted by collisional theory and can be justified considering synchrotron radiation losses. A new runaway electrons control algorithm was developed and tested in presence of a runaway current plateau, allowing to minimize the interactions with plasma facing components and safely shut down the discharges. The experimental sessions with 140GHz EC system have been mainly devoted to experiments on real-time control of magnetohydrodynamic (MHD) instabilities using the new EC launcher with fast steering capability. Experiments with central EC injection have shown the onset of 3/2 and 2/1 tearing modes, while EC assisted breakdown experiments have been focused on ITER start-up issues, exploring the polarization conversion at reflection from inner wall and the capability to assure plasma start-up even in presence of a large stray magnetic field. A new actively cooled lithium limiter has been installed and tested. The lithium limiter was inserted in the scrape-off layer, without any damage to the limiter surface. First elongated FTU plasmas with EC additional heating were obtained with the new cooled limiter. Density peaking and controlled MHD activity driven by neon injection were investigated at different plasma parameters. A full real-time algorithm for disruption prediction, based on MHD activity signals from Mirnov coils, was developed exploiting a large database of disruptions. Reciprocating Langmuir probes were used to measure the heat flux e-folding length in the scrape-off layer, with the plasma kept to lay on thea internal limiter to resemble the ITER start-up phase. New diagnostics were successfully installed and tested, as a diamond probe to detect Cherenkov radiation produced by fast electrons and a gamma camera for runaway electrons studies. Laser induced breakdown spectroscopy measurements were performed under vacuum and with toroidal magnetic field, so demonstrating their capability to provide useful information on the surface elemental composition and fuel retention in present and future tokamaks, such as ITER. © 2015 EURATOM.

Published
2009

12. Preliminary Results of the C-STAR Project at IRST

Author

B. Angelini, M. Cettolo, D. Falavigna, A. Lavelli, G. Lazzari, F. Pianesi, O. Stock, CORAZZA, ANNA, B., Angelini, M., Cettolo, Corazza, Anna, D., Falavigna, A., Lavelli, G., Lazzari, F., Pianesi, and O., Stock

Published
1996

13. ITB formation with counter ECCD and LHCD and Suprathermal ECCD experiments on FTU in ITER relevant conditions

Author

Maria Ester Puiatti, Gian Luca Ravera, F. Crisanti, Fulvio Zonca, H. Kroegler, S V Annibaldi, L. Gabellieri, M. Marinucci, G. Monari, J Berrino, D. Pacella, A. Bertocchi, Francesco Romanelli, B. Tilia, O. Tudisco, P. Smeulders, E. Barbato, G.B. Righetti, D. Frigione, S. Nowak, M.L. Apicella, Daniela Farina, R. DeAngelis, Francesco Mirizzi, V. Cocilovo, F. Gandini, M. Romanelli, C. Mazzotta, M. Panella, Gregorio Vlad, E. Giovannozzi, E. Lazzaro, Lorella Carraro, Gustavo Granucci, P. Buratti, Daniele Marocco, C. Centioli, M. Leigheb, E. Sternini, Basilio Esposito, S. Cirant, F.P. Orsitto, L. Panaccione, V. Vitale, G. Calabrò, V. Pericoli-Ridolfini, B. Angelini, S. Podda, F. Iannone, C. Castaldo, Alessandro Simonetto, L. Pieroni, F. De Marco, G. Apruzzese, M. De Benedetti, R. Cesario, G Regnoli, G. Mazzitelli, Angelo A. Tuccillo, Alessandro Bruschi, Carlo Sozzi, and A. Cardinali

Subjects
History, Tokamak, Toroid, Chemistry, Plasma, Resonant absorption, Electron, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Computer Science Applications, Education, law.invention, Computational physics, symbols.namesake, law, Physics::Plasma Physics, symbols, ____, Atomic physics, Absorption (electromagnetic radiation), Doppler effect
Abstract

In this paper the results of the experiments of combined injection of LH waves and EC waves performed in the FTU tokamak are reported. Such experiments were mainly devoted to study and to control the access to the advanced tokamak scenarios in plasma conditions close to ITER parameters (Bt≈5T or higher, ne,line≈10 20 m -3 ). Two different absorption mechanisms were used for the EC waves. In the first one the cold resonance absorption of EC waves launched with a toroidal angle was used to induce small modification of the current profile mainly maintained by LH waves. In the second one the absorption through Doppler shift due to the fast electron tails generated by LHCD was used.

Published
2005

14. Improved confinement produced by ion Bernstein waves in hydrogen and deuterium plasmas of FTU

Author

M. Marinucci, M.L. Apicella, V. Vitale, E. Barbato, Fulvio Zonca, A. Bertocchi, V. Pericoli-Ridolfini, L. Gabellieri, F. Crisanti, G. L. Ravera, G. Monari, N. Tartoni, B. Angelini, M. Zerbini, P. Orsitto, G. Apruzzese, G. Mazzitelli, R. De Angelis, M. Panella, P. Micozzi, E. Giovannozzi, L. Panaccione, F. De Marco, Cristina Centioli, G.B. Righetti, C. Gormezano, H. Kroegler, P. Papitto, D. Pacella, Luciano Bertalot, O. Tudisco, C. Castaldo, Gregorio Vlad, G. Buceti, L. Pieroni, Francesco Romanelli, A. A. Tuccillo, G. Maddaluno, V. Cocilovo, E. Sternini, F. Iannone, A. Cardinali, M. Leigheb, B. Esposito, and R. Cesario

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, Frascati Tokamak Upgrade, chemistry.chemical_element, Magnetic confinement fusion, Plasma, Radius, Condensed Matter Physics, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Ion, Deuterium, chemistry, Physics::Plasma Physics, Electron thermal conductivity, Atomic physics
Abstract

New experiments with the ion Bernstein waves (IBWs) have been performed in the Frascati Tokamak Upgrade (FTU) both in hydrogen and deuterium plasmas at higher power level, operation at higher density, higher plasma current and lower effective ion charge values than in the previous campaign. Improved confinement in a region with larger radius is obtained when operating in deuterium. Transport analysis shows a uniform decrease of the electron thermal conductivity by 40% over the radial region bounded by the absorption layer.

Published
2004

15. Overview of the FTU results

Author

B Angelini, M.L Apicella, G Apruzzese, E Barbato, A Bertocchi, G Bracco, A Bruschi, G Buceti, P Buratti, A Cardinali, L Carraro, C Castaldo, C Centioli, R Cesario, S Cirant, V Cocilovo, F Crisanti, R. De Angelis, M. De Benedetti, G Giruzzi, F. De Marco, B Esposito, M Finkenthal, D Frigione, L Gabellieri, F Gandini, L Garzotti, G Gatti, E Giovannozzi, C Gormezano, F Gravanti, G Granucci, M Grolli, F Iannone, H Kroegler, E Lazzaro, M Leigheb, G Maddaluno, G Maffia, M Marinucci, M Mattioli, G Mazzitelli, F Mirizzi, S Nowak, D Pacella, L Panaccione, M Panella, P Papitto, V Pericoli-Ridolfini, A.A Petrov, L Pieroni, S Podda, F Poli, M.E Puiatti, G Ravera, G.B Righetti, F Romanelli, M Romanelli, F Santini, M Sassi, A Saviliev, P Scarin, S.E Segre, A Simonetto, P Smeulders, E Sternini, C Sozzi, N Tartoni, B Tilia, A.A Tuccillo, O Tudisco, M Valisa, V Vershkov, V Vitale, G Vlad, V Zanza, M Zerbini, and F Zonca

Subjects
Nuclear and High Energy Physics, ___, Physics::Plasma Physics, Condensed Matter Physics, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Abstract

An overview of the Frascati tokamak upgrade (FTU) results during the period 2000-2002 is presented. Long duration internal transport barriers (ITBs) have been obtained on FTU with combined injection of lower hybrid (LH) and electron cyclotron (EC) waves in 5 T/0.5 MA discharges. The ITB phase lasts about 10 energy confinement times and is characterized by an energy confinement time up to 1.6 times the ITER97 L-mode scaling. Temperatures up to I I keV are measured at 0.9 x 10(20) m(-3) central density. ITB studies using IBW injection have also been continued up to 8 T/0.8 MA. The LH system has operated at full power allowing us to complete the current drive (CD) studies at ITER-relevant densities. At these density values the electrons and ions are coupled and an increase in the ion temperature is clearly observed. A preliminary sign of enhanced CD efficiency has been obtained in the combined injection of EC and LH waves at magnetic field values lower than the resonant field for thermal EC absorption. Pellet optimization studies have been performed in order to test the conditions under which a quasi-steady-state confinement improvement can be obtained and impurity accumulation can be avoided. The confinement time in Ohmic discharges is generally in agreement with the ITER97 L-mode scaling. Transient confinement improvement is observed for a duration less than one energy confinement time. Radiation improved mode studies have been started thanks to the recently inserted boronization system, which has allowed reduction of the radiated power. Confinement improvement with neon injection has been observed in 6 T/0.9 MA discharges. Transport studies on profile stiffness and magnetohydrodynamic (MHD) studies of fast reconnection and snakes will also be presented.

Published
2003

16. Investigation of high density regimes in FTU by pellet injection and impurity seeding

Author

D. Frigione, P. Buratti, M. De Benedetti, B. Esposito, L. Gabellieri, L. Garzotti, E. Giovannozzi, M. Leigheb, M. Marinucci, M. Mattioli, L. Pieroni, M. Romanelli, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Bracco, G. Buceti, A. Cardinali, C. Castaldo, C. Centioli, R. Cesario, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, G. Gatti, C. Gormezano, F. Gravanti, M. Grolli, F. Iannone, H. Kroegler, G. Maddaluno, G. Maffia, G. Mazzitelli, F. Mirizzi, D. Pacella, L. Panaccione, M. Panella, V. Pericoli-Ridolfini, S. Podda, F. Poli, G.B. Righetti, F. Romanelli, F. Santini, S.E. Segre, P. Smeulders, E. Sternini, N. Tartoni, B. Tilia, A. A. Tuccillo, O. Tudisco, V. Vitale, V. Zanza, and M. Zerbini

Subjects
Physics::Plasma Physics
Abstract

High field pellet fuelled discharges in FTU have achieved good energy and particle confinement properties in ohmic quasi-steady regime. Peak densities close to 1x1021 m-3 have been obtained, showing a post pellet decay time of several energy confinement times. Experiments aimed at obtaining Radiative Improved Modes (RIM) at high field have also been carried out using Neon injection. We have observed an increase of average density with respect to the reference discharge, which cannot be explained by the contribution of Neon. The neutron yield increases also by a factor 3- 6 and the energy confinement time increases by a factor 1.4

Published
2003

17. Local Improvement Confinement in the Ion Bernstein (IBW) Experiment on FTU (Frascati Tokamak Upgrade)

Author

F. Paoletti, L. Gabellieri, B. Angelini, G. Monari, C. Gormezano, H. Kroegler, M. Zerbini, A. A. Tuccillo, A. Bertocchi, E. Giovannozzi, D. Pacella, G. Mazzitelli, Fulvio Zonca, G. Maddaluno, P. Orsitto, L. Pieroni, F. De Marco, S. Bernabei, P. Micozzi, Gregorio Vlad, V. Vitale, L. Panaccione, G. Buceti, Luciano Bertalot, V. Pericoli-Ridolfini, Cristina Centioli, M.L. Apicella, R. Cesario, F. Crisanti, V. Cocilovo, M. Grolli, F. Iannone, Francesco Romanelli, E. Barbato, M. Marinucci, A. Cardinali, G.B. Righetti, P. Papitto, E. Sternini, M. Leigheb, B. Esposito, Giancarlo Gatti, G. Apruzzese, O. Tudisco, G. L. Ravera, N. Tartoni, R. De Angelis, M. Panella, and C. Castaldo

Subjects
Tokamak, Toroid, Deuterium, Physics::Plasma Physics, Chemistry, law, Frascati Tokamak Upgrade, Plasma, Atomic physics, Electromagnetic radiation, Magnetic field, law.invention, Ion
Abstract

New experiments with the ion Bernstein waves (IBW) has been performed on FTU both in Hydrogen (H) and Deuterium (D) majority plasmas, at higher radio‐frequency power level, plasma density, current, lower effective ion charge than in previous campaign of 1999. Also in these conditions, no role is played by non‐linear edge physics, which prevented, instead, the RF penetration in the plasma bulk of DIII‐D. With resonant toroidal magnetic field (≈8T), improved confinement occurs inside a radial region of 1/3 of the minor radius operating in H‐plasma, and 2/3 of the minor radius operating in D‐majority plasma. Such behavior is consistent with the model of turbulence suppression by locally‐induced‐IBW‐sheared flow expected to occur close the resonant layer. The FTU results provide support for active control of the pressure profile by IBW which is of relevance for advanced tokamaks .

Published
2003

18. High power heating and current drive experiments with EC waves in FTU tokamak

Author

D. Frigione, Francesco Romanelli, G.B. Righetti, R. Coelho, Gustavo Granucci, P. Orsitto, M. Panella, D. Pacella, S. Cirant, V. Vitale, Giovanna Cenacchi, Cristina Centioli, B. Angelini, A. A. Tuccillo, G. Maddaluno, M. Marinucci, S. Ciattaglia, Franco Gandini, M. Borra, V. Cocilovo, Giancarlo Gatti, Gregorio Vlad, Alessandro Bruschi, G. Buceti, Alessandro Simonetto, S. Nowak, E. Lazzaro, V. Zanza, E. Barbato, M. Zerbini, Luciano Bertalot, N. Tartoni, M. Grolli, P. Chuilon, Salvatore Podda, F. Crisanti, O. Tudisco, G. Mazzitelli, A. Airoldi, Carlo Sozzi, G. Ramponi, A. Cardinali, V. Pericoli, S. Sternini, R. De Angelis, M. Leigheb, L. Panaccione, B. Esposito, L. Pieroni, F. Iannone, R. Cesario, L. Gabellieri, E. Giovannozzi, A. Bertocchi, Giovanni Bracco, G. Apruzzese, H. Krögler, P. Micozzi, Fulvio Zonca, M.L. Apicella, F. Alladio, and P. Buratti

Subjects
Tokamak, Toroid, Chemistry, Physics, Fluids & Plasmas, Pulse duration, Plasma, law.invention, law, Physics::Plasma Physics, Electron temperature, Electric current, Atomic physics, Waveguide, Current density
Abstract

The EC system at 140 Ghz, 2 MW, being implemented on FTU tokamak for performing electron heating, profile control and current drive, is composed by four gyrotrons with 0.5 s pulse length capability, and four hybrid mirror/waveguide transmission lines. The launching system is capable of poloidal/toroidal beam steering through a set of tiltable in-vacuum mirrors, coupling to the O-mode at the fundamental resonance, with full control of the e.m. field polarization. Experiments have been made with two gyrotrons, by launching 0.8 MW to the plasma. In the high density regime (local n{sub e} from {approx_equal}0.8 up to 2 10{sup 20} m{sup -3}) the e-i energy transfer is significant, and ion heating is observed through the enhancement of the neutron emission in Deuterium plasmas. The highest electron heating is observed when on-axis ECRH is performed in the current ramp-up, sawtooth-free phase. In steady-state conditions, saw-tooth period is increased up to stabilization by off-axis ECRH. Localized ECCD is also performed to assist in the shaping of the current density profile.

Published
1999
Full Text
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19. Recent results of the ion Bernstein wave heating experiment on FTU

Author

G.B. Righetti, A. A. Tuccillo, P. Papitto, P. Orsitto, G. Maddaluno, M. Panella, O. Tudisco, S. Bernabei, Luciano Bertalot, L. Pieroni, Giovanni Bracco, P. Chuilon, G. L. Ravera, F. Alladio, V. Vitale, N. Tartoni, P. Buratti, V. Pericoli-Ridolfini, B. Angelini, M. Marinucci, G. Apruzzese, P. Micozzi, S. Cascino, V. Zanza, R. De Angelis, V. Cocilovo, F. Iannone, M. Leigheb, M. Zerbini, L. Panaccione, B. Esposito, M. Borra, G. Mazzitelli, Francesco Romanelli, D. Pacella, Giancarlo Gatti, S. Ciattaglia, C. Castaldo, F. Crisanti, M.L. Apicella, L. Gabellieri, F. De Marco, R. Cesario, D. Frigione, H. Kroegler, A. Cardinali, G. Monari, S. Sternini, Fulvio Zonca, E. Giovannozzi, A. Berttocchi, Cristina Centioli, E. Barbato, M. Grolli, Gregorio Vlad, G. Buceti, and Salvatore Podda

Subjects
Physics, Tokamak, Toroid, Physics::Plasma Physics, law, RF power amplifier, Electron temperature, Plasma, Atomic physics, Electromagnetic radiation, law.invention, Magnetic field, Ion
Abstract

About 400 kW of rf power at the frequency of 433 MHz were coupled to the plasma of the FTU tokamak by a waveguide antenna. During the experiment, a peaking of the Te and ne profiles and a Hα drop have been observed during the IBW pulse, only when operating with toroidal magnetic field value which allows the wave penetration to in the plasma bulk. Moreover, the electron temperature increased typically from about 2.5 keV to about 4.5 keV with a coupled power of about 350 kW; the line-averaged central plasma density increased from 3×1019 m−3 to about 5×1019 m−3.

Published
1999

20. Electron cyclotron heating experiments during the current ramp-up in FTU

Author

O. Tudisco, G. Bracco, P. Buratti, V. Zanza, F. Crisanti, S. Cirant1, G. Granucci1, G. Giruzzi2, V.Krivenski3, A. Bruschi1, S. Nowak1, A. Simonetto1, C. Sozzi1, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, L. Bertalot, A. Bertocchi, M. Borra, G. Buceti, A. Cardinali, S.Cascino, C. Centioli, R. Cesario, P. Chuilon, S. Ciattaglia, V. Cocilovo, R. De Angelis, B. Esposito, D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, M. Grolli, F. Iannone, H. Kroegler, M. Leigheb, G. Maddaluno, M. Marinucci, G. Mazzitelli, P. Micozzi, P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, S. Sternini, N. Tartoni, A.A. Tuccillo, V. Vitale, G. Vlad, M. Zerbini, and F. Zonca.

Subjects
___
Abstract

___

Published
1999

21. Impurity transport studies of intrinsic Mo and injected Ge in high temperature ECRH heated FTU tokamak plasmas

Author

D. Pacella, M. May1, K.B. Fournier 2, M. Finkenthal1, M. Mattioli3, M. Zerbini, M. Leigheb, L. Gabellieri, G. Bracco, F. Crisanti, G. Granucci4, M. Marinucci, C. Sozzi4, O. Tudisco, G. Giruzzi2, P. Buratti, V. Zanza, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, L. Bertalot, A. Bertocchi, M. Borra, G. Buceti, A. Cardinali, S. Cascino, C. Centioli, R. Cesario, P. Chuilon, S. Ciattaglia, V. Cocilovo, R. De Angelis, B. Esposito, D. Frigione, G. Gatti, E. Giovannozzi, M. Grolli, F. Iannone, H. Kroegler, G. Maddaluno, G. Mazzitelli, P. Micozzi, P. Orsitto, L. Panaccione, M. Panella, V. Pericoli, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, S. Sternini, N. Tartoni, A.A. Tuccillo, V. Vitale, G. Vlad, F. Zonca, A. Bruschi1, S. Cirant1, S. Nowak1, A. Simonetto1, V. Mellera1, V. Muzzini1, F. Gandini1, R. Bozzi1, and N. Spinicchia1

Subjects
___
Abstract

___

Published
1999

22. [Balance sheet of tolerance-efficacy on the use of tacrine in 100 cases of Alzheimer's disease]

Author

M C, Estadieu, C, Machou, P, Berthezène, M J, Pastor, B, Angelini, M, Bohor, M C, Bongrand, P, Timon-David, J L, Gastaut, H, Allain, and B F, Michel

Subjects
Aged, 80 and over, Male, Time Factors, Alanine Transaminase, Middle Aged, Treatment Outcome, Liver, Alzheimer Disease, Tacrine, Humans, Female, Mental Status Schedule, Nootropic Agents, Aged, Follow-Up Studies
Abstract

We report our first 100 cases of Alzheimer's (AD) patients treated with tacrine (Cognex) for a period of one year. At the beginning of treatment the mean Mini-Mental-Status (MMS) score was 15.1. To date 71 patients are still under treatment (12 for more than 12 months). Forty-three instances of side-effects were observed, of which 31 involved hepatic side-effects with an increase in ALATIN (normal value) (6 cases3N), the mean date of appearance was 10.4 +/- 6.8 weeks, there were 16 cholinergic side-effects (nausea, vomiting, diarrhoea), plus 4 neurologic and 2 cutaneous side-effects. These side-effects led to the arrest of the treatment in 19 cases (16 for hepatic toxicity). Treatment was reattempted after interruption in 13 cases; successfully in 3 instances only. The measure of tacrine efficacy was based on 52 MMS score re-evaluations in week 18: there was an increase of the MMS score in 22 cases (3.3 points +/- 2.5), a stabilisation in 11 cases and a decrease in 19 cases (3.3 points +/- 2.2.). In week 30, the MMS scores (35 patients) increased in 9 cases (3.6 points +/- 2.4), stabilized in 5 cases and decreased in 21 cases (3.9 points +/- 3.3). At week 52, only 28 per cent of the patients were considered as either improved or stabilized. We conclude that there is a necessity for close follow-up of tacrine-treated patients, and that globally at 8 months there is an improvement or a stabilization in 40 per cent of patients and long term (at one year) a stabilizing effect on AD patients.

Published
1998

23. Edge and bulk variations of plasma induced by Kr and Ar injection in FTU

Author

D. Pacella, B.C. Gregory1, M. Leigheb, G. Pizzicaroli, G. Mazzitelli, M. Borra, L. Pieroni, M. May2, K.B. Fournier3, W.H. Goldstein3, M. Finkentha12, M. Mattioli4, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, S. Belforte, L. Bertalot, A. Bertocchi, G. Bracco, A.Bruschi5, G. Buceti, P Buratti, A Cardinali, C. Castaldo, C. Centioli, R. Cesario, P. Chuilon, C. Cianfarani, Ciattaglia, S. Cirant5, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, B.Esposito, D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, C. Gourlan, F. Gravanti, G. Gravanti, G. Granucci5, M Grolli, F. Iannone, H Kroegler, G. Maddaluno, G. Maffia, M. Marinucci, P. Micozzi, F. Mirizzi, F.P. Orsitto, L. Panaccione, M. Panella, V. Pericoli-Ridolfini, S. Podda, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre6, E. Stemini, A. Simonetto5, C. Sozzi5, N. Tartoni, B. Tilia, A.A. Tuccillo, O. Tudisco, V. Vitale, G. Vlad, V. Zanza, M. Zerbini, and F. Zonca

Subjects
___
Abstract

___

Published
1998

24. Transport studies during ECRH in monotonic-q and shear-reversed FTU plasmas

Author

S. Cirant, P. Buratti, G. Bracco, A. Bruschi, F. De Luca+, G. Granucci, A. Jacchia, S. Nowak, A. Simonetto, C. Sozzi, O. Tudisco, M. Zerbini, L. Acitelli, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, L. Bertalot, A. Bertocchi, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, C. Cianfarani, S. Ciattaglia, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, B. Esposito, D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, C. Gourlan, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, L. Lovisetto, G. Maddaluno, G. Maffia, M. Marinucci, G. Mazzitelli, P. Micozzi, F. Mirizzi, F.P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli Ridolfini, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre, S. Sternini, A.A. Tuccillo, V. Vitale, G. Vlad, V. Zanza, and F. Zonca

Subjects
___
Abstract

___

Published
1998

25. Sawteeth stabilization and ion temperature enhancement by localized ECRH in FTU plasmas

Author

S. Cirant, A. Airoldi, L. Bertalot, G. Bracco, A. Bruschi, P. Buratti, A. Cenacchi+, B. Esposito, G. Gervasini, G. Granucci, E. Lazzaro, S. Nowak, G. Ramponi, A. Simonetto, C. Sozzi, O. Tudisco, M. Zerbini, F. Alladio, L. Acitelli, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, C. Cianfarani, S. Ciattaglia, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, D. Frigione, L. Gabellieri, G. Gatti, C. Gourlan, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, E. Giovannozzi, G. Maddaluno, G. Maffia, M. Marinucci, G. Mazziteli, F. Mirizzi, F.P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli Ridolfini, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre, S. Sternini, A.A. Tuccillo, V. Vitale* G. Vlad, V. Zanza, and F. Zonca

Subjects
__
Abstract

___

Published
1998

26. High density operation in the FTU tokamak with LH and ECRH

Author

V. Pericoli Ridolfini, S. Cirant, E. Barbato, M.Borra, A. Bruschi, P. Buratti, G. Granucci, S.Nowak, D. Pacella, L. Panaccione, S. Podda, A. Simonetto, C. Sozzi, A.A. Tuccillo, M. Zerbini, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, L. Bertalot, A. Bertocchi, G. Bracco, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, S. Ciattaglia, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, B. Esposito, D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, G. Gourlan, F. Gravanti, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, G. Maddaluno, G. Maffia, A. Mancuso, M. Marinucci, G. Mazzitelli, P. Micozzi, F. Mirizzi, E.P. Orsitto, M. Panella, L. Pieroni, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre, B.Tillia, E.Sternini, O. Tudisco, V. Vitale, G. Vlad, and V. Zanza

Subjects
___
Abstract

__

Published
1998

27. Internal MHD modes in FTU plasmas with high core confinement

Author

P. Buratti, F. Alladio, G. Bracco, A. Bruschi, S. Ciran1, D. Frigione, E. Giovannozzi, G. Granucci1, P. Micozzi, S. Nowak1, A. Simonetto1, C. Sozzi1, M. Zerbini, L. Acitelli, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, L. Bertalot, A. Bertocchi, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, C. Cianfarani, S. Ciattaglia, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, B. Esposito, L. Gabellieri, G. Gatti, C. Gourlan, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, L. Lovisetto, G. Maddaluno, G. Maffia, M. Marinucci, G. Mazzitelli, F. Mirizzi, F.P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli Ridolfini, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre2, S. Sternini, A.A. Tuccillo, 0. Tudisco, V. Vitale, G. Vlad, V. Zanza, and F. Zonca

Subjects
___
Abstract

__

Published
1998

28. Improved confinement on FTU sustained by multiple pellet injection

Author

D. Frigione, S. Cirant, E. Giovannozzi, P. Micozzi, L. Acitelli, P. Buratti, O. Tudisco, V. Zanza, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Bracco, A. Bruschi, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, S. Ciattaglia, M. Ciotti, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, Bv. Esposito, L. Gabellieri, G. Gatti, G. Gourlan, G. Granucci, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, L. Lovisetto, G. Maddaluno, G. Maffia, A. Mancuso, M. Marinucci, G. Mazzitelli, F. Mirizzi, E.P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli Ridolfini, L. Pieroni, S. Podda, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre, A. Simonetto, C. Sozzi, S. Sternini, A.A. Tuccillo, F. Valente, V. Vitale, G. Vlad, and M. Zerbini

Published
1997

29. Sawtooth stabilization on the FTU tokamak

Author

P. Buratti, O. Tudisco, L. Panaccione, L. Acitelli, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Bracco, A. Bruschi, G. Buceti, A. Cardinali, C. Centioli, R. Cesario, S. Ciattaglia, M. Ciotti, S. Cirant, V. Cocilovo, F. Crisanti, R. De Angelis, F. De Marco, B. Esposito, D. Frigione, L. Gabbellieri, G. Gatti, E. Giovannozzi, C. Gourlan, G. Granucci, M. Grolli, A. Imparato, H. Kroegler, M. Leigheb, L. Lovisetto, G. Maddaluno, G. Maffia, A. Mancuso, M. Marinucci, G. Mazzitelli, P. Micozzi, F. Mirizzi, F.P. Orsitto, D. Pacella, M. Panella, V. Pericoli Ridolfini, L. Pieroni, G.B. Righetti, S. Podda, F. Romanelli, F. Snatini, M. Sassi, S.E. Segre, A. Simonetto, C. Sozzi, S. Sternini, A.A. Tuccillo, F. Valente, V. Vitale, G. Vlad, V. Zanza, and M. Zerbini

Published
1997

30. Lower hybrid current drive in FTU high density shear reversed discharges

Author

D. Pacella, S. Ciattaglia, D. Frigione, H. Kroegler, B. Angelini, S. Cirant, O. Tudisco, Alessandro Bruschi, F. Santini, Carlo Sozzi, L. Panaccione, Marco Ciotti, F. De Marco, E. Barbato, V. Vitale, Francesco Romanelli, A. Bertocchi, F. Crisanti, A. A. Tuccillo, R. De Angelis, L. Gabellieri, L. Acitelli, M. Marinucci, C. Gourlan, Giovanni Bracco, M. Zerbini, Gregorio Vlad, G. Maddaluno, P. Orsitto, S. Podda, A. Imparato, G. Apruzzese, G. Mazzitelli, G. Buceti, Alessandro Mancuso, M.L. Apicella, P. Micozzi, M. Borra, S. Sternini, Giancarlo Gatti, Alessandro Simonetto, V. Cocilovo, L. Pieroni, V. Pericoli, E. Giovannozzi, M. Leigheb, B. Esposito, G.B. Righetti, L. Lovisetto, A. Cardinali, Gustavo Granucci, F. Alladio, V. Zanza, F. Valente, P. Buratti, M. Panella, Francesco Mirizzi, R. Cesario, Cristina Centioli, P. Amadeo, G. Maffia, and M. Grolli

Subjects
Amplitude, Chemistry, Physics, Fluids & Plasmas, Limiter, Analytical chemistry, Figure of merit, Electron temperature, Plasma, Radius, Electron, Atomic physics, Magnetic field
Abstract

Results are reported of the 8 GHz Lower Hybrid experiments on FTU after the installation of the new toroidal limiter. A figure of merit of the Current Drive efficiency eta(CD) approximate to 0.11.10(20) A/Wm(2) is estimated for plasma density = 10(20) m(-3) and no appreciable broadening of the launched frequency is detected. In low density experiments sawteeth are stabilised and m = 1 activity is present in the plasma. Shear reversed discharges with large reversal radius, r(S)/a approximate to 0.5, are obtained at higher density, lower temperature, B-T = 4 T, q(a) approximate to 5.5, by off-axis LH CD. The reversed configurations exhibit high central temperature coexisting with regular m = 2, n = 1 relaxations of large amplitude and are maintained up to LH switch off. At higher magnetic field, B = 5.2 T, q(a) approximate to 7, irregular DTM crashes are present during the whole LH pulse. Confinement time of radiofrequency heated discharges (P-LH = 0.5 divided by 2.P-OH) exhibits the same behaviour of FTU ohmic discharges following the ITER89-P scaling. Preliminary results of central 140 GHz Electron Cyclotron Resonant Heating (ECRH) during the plasma current ramp-up, aimed at obtaining shear reversed configurations are also reported.

Published
1997

31. Current drive experiments at high density in the FTU Tokamak

Author

V. Pericoli Ridolfini, S. Cirant, H. Kroegler, L. Panaccione, S. Podda, P. Buratti, O. Tudisco, G. Giruzzi, L. Acitelli, F. Alladio, B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Bracco, A. Bruschi, G. Buceti, A. Cardinali, C. Centionli, R. Cesario, S. Ciattaglia, M. Ciotti, V. Cocilovo, F. Crfisanti, R. De Angelis, F. De Marco, B. Esposito D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, C. Gourland, G. Granucci, M. Grolli, A. Imparato, M. Leigheb, L. Lovisetto, G. Maddaluno, G. Maffia, A. Mancuso, M. Marinucci, G. Mazzitelli, P. Micozzi, F. Mirizzi, F.P. Orsitto, D. Pacella, M. Panella, L. Pieroni, G.B. Righetti, F. Romanelli, F. Santini, M. Sassi, S.E. Segre, A. Simonetti, S. Sternini, A.A.A Tuccillo, F. Valente, V. Vitale, G. Vlad, V. Zanza, M. Zerbini, and C. Sozzi

Subjects
__
Abstract

__

Published
1997

32. The Frascati Tokamak Upgrade machine: plant and operation status

Author

E. Sternini, G. Buceti, B. Angelini, F. Gravanti, G. Mazzitelli, F. Crisanti, M Panella, S. Ciattaglia, V Zanza, and Angelo A. Tuccillo

Subjects
Engineering, business.industry, Nuclear engineering, Frascati Tokamak Upgrade, business, Term (time)
Abstract

This paper presents a general overview of the Frascati Tokamak Upgrade (FTU) machine. The status of the major systems and the relevant upgrades are discussed together with a few data on the operation status and the operating experience, and the near term improvements and programme.

Published
1997

33. Speedata: multilingual spoken data entry

Author

R. Gretter, Diego Giuliani, Marcello Federico, Heinrich Niemann, G. Lazzari, F. Brugnara, B. Angelini, and U. Ackermann

Subjects
Register (sociolinguistics), Computer science, business.industry, First language, Speech technology, computer.software_genre, Variety (linguistics), Linguistics, language.human_language, German, Application domain, language, Proper noun, Artificial intelligence, business, computer, Natural language, Natural language processing
Abstract

The authors present a multilingual application for speech technology. The SpeeData project aims at building a demonstrator that provides a user-friendly interface for spoken data-entry in two languages: Italian and German. The application domain is the land register of an Italian region in which both languages are officially spoken. The considered data-entry task is particularly challenging as it considers many different types of data-e.g. long texts, numbers, proper names, tables, etc.-and a variety of of pronunciations, since dialects are present and users will not always speak in their native language.

Published
1996

34. Automatic Speech Labeling Using Word Pronunciation Networks and Hidden Markov Models

Author

R. Gretter, D. Falavigna, D. Giuliani, M. Omologo, B. Angelini, and F. Brugnara

Subjects
Set (abstract data type), ComputingMethodologies_PATTERNRECOGNITION, Computer science, Speech recognition, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Segmentation, TIMIT, Pronunciation, Hidden Markov model, Word (computer architecture), Sequence labeling, Sentence
Abstract

A system for automatic labeling and segmentation of speech signals starting from their corresponding text will be described2. The system uses continuous Hidden Markov Models (HMM) to represent a predefined set of acoustic-phonetic units and pronunciation networks to allow different phonetic realizations of a given sentence. The system has been applied to an American (TIMIT) and an Italian (APASCI) speech database.

Published
1995

36. Overview of the FTU results.

Author

B. Angelini, M.L. Apicella, G. Apruzzese, E. Barbato, A. Bertocchi, G. Bracco, A. Bruschi, G. Buceti, P. Buratti, A. Cardinali, L. Carraro, C. Castaldo, C. Centioli, R. Cesario, S. Cirant, V. Cocilovo, F. Crisanti, R. De Angelis, M. De Benedetti, and G. Giruzzi

Published
2003

41. Overview of the FTU results.

Author

G. Pucella, E. Alessi, B. Angelini, M.L. Apicella, G. Apruzzese, G. Artaserse, B. Baiocchi, F. Belli, W. Bin, F. Bombarda, L. Boncagni, A. Botrugno, S. Briguglio, A. Bruschi, P. Buratti, G. Calabrò, M. Cappelli, A. Cardinali, D. Carnevale, and L. Carraro

Subjects
LASER-induced breakdown spectroscopy, ELECTRON spectroscopy, SPECTRAL imaging, THOMSON scattering, LINEAR codes
Abstract

Since the 2016 IAEA Fusion Energy Conference, FTU operations have been mainly devoted to experiments on runaway electrons and investigations into a tin liquid limiter; other experiments have involved studies of elongated plasmas and dust. The tearing mode onset in the high density regime has been studied by means of the linear resistive code MARS, and the highly collisional regimes have been investigated. New diagnostics, such as a runaway electron imaging spectroscopy system for in-flight runaway studies and a triple Cherenkov probe for the measurement of escaping electrons, have been successfully installed and tested, and new capabilities of the collective Thomson scattering and the laser induced breakdown spectroscopy diagnostics have been explored. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
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42. High plasma density lower-hybrid current drive in the FTU Tokamak

Author

L. Gabellieri, C. Gourlan, G. Maddaluno, G. Maffia, E. Barbato, L. Pieroni, Alessandro Simonetto, A. A. Tuccillo, F. Gravanti, F. Santini, R. Cesario, Gustavo Granucci, B. Angelini, E. Giovannozzi, S. Nowak, Gregorio Vlad, Francesco Romanelli, M. Marinucci, G. Buceti, S. E. Segre, L. Lovisetto, A. Bertocchi, M. Sassi, D. Frigione, S. Cirant, A. Imparato, H. Kroegler, E. Sternini, Cristina Centioli, L. Panaccione, Salvatore Podda, D. Pacella, V. Cocilovo, Francesco Mirizzi, S. Ciattaglia, V. Vitale, Alessandro Bruschi, M. Grolli, A. Cardinali, G.B. Righetti, V. Pericoli-Ridolfini, Luciano Bertalot, V. Zanza, B. Tilia, Giovanni Bracco, G. Apruzzese, M. Panella, M. Leigheb, M. Zerbini, N. Tartoni, G. Mazzitelli, Carlo Sozzi, B. Esposito, R. De Angelis, F. De Marco, F. Alladio, P. Buratti, F.P. Orsitto, F. Crisanti, Fulvio Zonca, P. Micozzi, M.L. Apicella, O. Tudisco, M. Borra, and Giancarlo Gatti

Subjects
Nuclear physics, Physics, Part iii, Tokamak, ___, law, High plasma, General Physics and Astronomy, Plasma, Current (fluid), Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), law.invention
Abstract

s Vol. 19C (European Physical Society, Geneva, 1995), Part III, p. 361. [15] G. Tonon et al., Plasma Phys. Controlled Fusion 35, A105

43. Enhanced confinement regimes with strong electron heating in the presence of flat or inverted safety factor profiles

Author

E. Barbato, M.L. Apicella, B. Tilia, M. Leigheb, G. Apruzzese, E. Giovannozzi, L Gabellieri, N. Tartoni, L Bertalot, D. Frigione, P. Buratti, M Panella, G. Maffia, B. Angelini, C. Centioli, F. Gravanti, H. Kroegler, Alessandro Simonetto, Carlo Sozzi, M. Marinucci, L. Panaccione, F. Santini, F. P. Orsitto, V Cocilovo, R. De Angelis, A. Bertocchi, V. Pericoli-Ridolfini, F. Crisanti, Fulvio Zonca, C. Gourlan, S. Ciattaglia, C. Cianfarani, R. Cesario, F. Alladio, B. C. Gregory, Francesco Mirizzi, Angelo A. Tuccillo, Gregorio Vlad, Alessandro Bruschi, M. Sassi, M R Belforte, P. Chuilon, C. Castaldo, B Esposito, G. Maddaluno, F. Iannone, M. Borra, G. Buceti, Francesco Romanelli, A. Cardinali, L. Pieroni, O. Tudisco, D. Pacella, G. Bracco, S. Podda, M. Grolli, G.B. Righetti, Gustavo Granucci, M. Zerbini, S. E. Segre, G. Mazzitelli, S Cirant, F. De Marco, E. Sternini, V Vitale, G Gatti, P Micozzi, and V Zanza

Subjects
Materials science, Safety factor, Tokamak, Frascati Tokamak Upgrade, Condensed Matter Physics, equipment and supplies, Electron transport chain, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Electron cyclotron resonance, law.invention, Shear (sheet metal), Nuclear Energy and Engineering, ___, law, Physics::Plasma Physics, Magnetohydrodynamic drive, Atomic physics, Magnetohydrodynamics, human activities
Abstract

The role of magnetic shear in affecting electron transport is discussed on the basis of the Frascati tokamak upgrade (FTU) data with central electron cyclotron resonance heating (ECRH) on the current ramp phase and with pellet injection. The results point out that strongly negative magnetic shear is not a necessary condition in order to have good electron transport and that magnetohydrodynamic (MHD) activity plays a crucial role in affecting the electron transport in the region with low/negative magnetic shear. The theoretical arguments for the dependence of transport on magnetic shear are reviewed and compared with the experimental evidence.

44. Dynamics of tearing modes during strong electron cyclotron heating on the FTU tokamak

Author

E. Lazzaro, A. Airoldi, A. Bruschi, P. Buratti, S. Cirant, R. Coelho, G. Granucci, S. Nowak, G. Ramponi, A. Simonetto, C. Sozzi, O. Tudisco, G. Bracco, F. Crisanti, F. Alladio, B. Angelini, M. L. Apicella, G. Apruzzese, E. Barbato, L. Bertalot, A. Bertocchi, M. Borra, G. Buceti, A. Cardinali, S. Cascino, C. Centioli, R. Cesario, S. Ciattaglia, V. Cocilovo, R. De Angelis, B. Esposito, D. Frigione, L. Gabellieri, G. Gatti, E. Giovannozzi, M. Grolli, F. Iannone, H. Kroegler, M. Leigheb, G. Maddaluno, M. Marinucci, G. Mazzitelli, P. Micozzi, G. Monari, P. Orsitto, D. Pacella, L. Panaccione, M. Panella, V. Pericoli, L. Pieroni, S. Podda, G. Pucella, G. B. Righetti, F. Romanelli, S. Sternini, N. Tartoni, A. A. Tuccillo, V. Vitale, G. Vlad, V. Zanza, M. Zerbini, and F. Zonca

Subjects
Physics, Tokamak, Toroid, Cyclotron, General Physics and Astronomy, Atmospheric-pressure plasma, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Electron cyclotron resonance, law.invention, ___, law, Physics::Plasma Physics, Mode coupling, Physics::Space Physics, Electron temperature, Atomic physics, Magnetohydrodynamics
Abstract

The localized electron cyclotron resonance heating power that can suppress sawteeth reconnection often drives m 2 tearing modes in a tokamak operating at constant current. The dynamics of mode onset and coupled mode evolution is described in detail and compared with a nonlinear theoretical model that identifies the effects of mode coupling, finite inertia of the rotating islands, and wall braking. PACS numbers: 52.35.Py The observation of enhanced magnetohydrodynamic (MHD) fluctuations of the tearing type affecting the plasma energy transport in additionally heated tokamaks stimulates great interest in gathering experimental knowledge and understanding of the detailed mechanisms of these instabilities for finding a possible strategy for their active control in resistive and neoclassical regimes. In this Letter, we report the experimental evidence on the FTU tokamak and interpretation of two significant types of response of low order resistive MHD perturbations to the effects of temperature profile changes induced by localized heating. In one case the sawteeth instability is suppressed and an isolated m 2 rotating tearing mode is driven; in another case m 1 and m 2 tearing modes are driven. We identify for the first time the detailed mechanism governing the rotation of toroidally coupled and uncoupled magnetic islands, associated to finite inertia and wall braking. High power electron cyclotron resonance heating (ECRH) is used for controlling the MHD activity by fine adjustments of the position of the rf power absorbing layer [1,2]. The fundamental resonance scheme at 140 Ghz was used. A power P EC 800 kW was injected in plasmas with major radius R0 0.97 m, minor radius a 0.27 m, toroidal magnetic field B 4 6 T, low plasma current (Ip 350 kA) and high values of the safety factor qa 6. At these qa values, sawtooth relaxations are small or absent, while MHD oscillations with poloidal number m 2 are observed in many cases. As a consequence of a moderate reshaping of the current density profile and of a substantial increase of the plasma pressure induced by ECRH near q 1, MHD oscillations near q 2 are strongly amplified (Fig. 1). The oscillations are detected by a fast electron cyclotron emission (ECE) multichannel polychromator, by an array of detectors for soft-x-ray tomography, and by a set of Mirnov coils. Cross-correlation analysis shows that the poloidal and toroidal periodicity of these fluctuations is m 2, n 1 across most of the plasma section. In some cases, an m 1, n 1 component is detected in the central region. As shown in Fig. 2, the poloidal pattern of softx-ray emissivity has an even m periodicity that is confirmed by Mirnov coils signals to be m 2. The phasing between the oscillations in the ECE and soft-x-ray diagnostics, placed at different toroidal angles, is consistent with an n 1 toroidal order. The fast measurements of the electron temperature profile (Fig. 3), taken at different times during the island rotation, show a change in the slope around rq2 as the measurement happens to be alternatively on or near the “X” point (t 0.66035 and t 0.6592) and the “O” point during rotation. A

45. Transport and MHD studies at high Te in FTU tokamak

Author

S. Podda, E. Barbato, M.L. Apicella, M. Grolli, Angelo A. Tuccillo, G. Maddaluno, S. E. Segre, M. Marinucci, B Esposito, G. Apruzzese, B. Angelini, V Vitale, C. Centioli, G. Bracco, E. Lazzaro, L Bertalot, G Gatti, Gustavo Granucci, P. Orsitto, P Micozzi, S. Nowak, Giovanna Cenacchi, A. Bertocchi, L Gabellieri, E. Giovannozzi, A. Cardinali, G. Mazzitelli, S Cirant, V. Pericoli, M. Zerbini, V Zanza, D. Pacella, Francesco Romanelli, S. Ciattaglia, S. Sternini, M. Leigheb, D. Frigione, N. Tartoni, R Coelho, L. Pieroni, F. Alladio, G.B. Righetti, Alessandro Simonetto, Carlo Sozzi, F. Iannone, G. Ramponi, R. De Angelis, H. Krögler, M Panella, R. Cesario, F. Gandini, Alessandro Bruschi, V Cocilovo, Gregorio Vlad, G. Buceti, M. Borra, P. Chuilon, O. Tudisco, A Airoldi, F. Crisanti, Fulvio Zonca, P. Buratti, and L. Panaccione

Subjects
Physics, Tokamak, Toroid, Magnetic reconnection, Condensed Matter Physics, Thermal conduction, Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin), Electron cyclotron resonance, Computational physics, law.invention, ___, Nuclear Energy and Engineering, Physics::Plasma Physics, law, Mode coupling, Magnetohydrodynamic drive, Atomic physics, Magnetohydrodynamics
Abstract

Magnetohydrodynamic (MHD) activity and energy transport at rational-q surfaces is analysed on the basis of experimental results on current density profile control obtained with localized electron cyclotron resonance heating (ECRH) on FTU tokamak. The MHD response, in particular 2/1 and 1/1 modes, to ECRH is in agreement with expectations from a theoretical model including resistive wall braking and toroidal mode coupling. It is also shown that the magnetic shear at rq = 1 could control m = 1 mode saturation and magnetic reconnection. Heating results with ECRH at steady state indicate that transport enhancement is the dominant effect on confinement at the q = 2 surface, and suggest that conduction and convection inside the asymmetric m = 1 island should both be taken into account for a proper description of the thermal response to localized ECRH.

46. An overview of FTU results

Author

William Bin, G. Rocchi, Lorenzo Figini, G. Ramogida, Zwinglio Guimarães-Filho, Daniela Farina, C. Galperti, E. Giovannozzi, S. Nowak, D. Frigione, R. Tulli, H. Kroegler, A. Sibio, M. De Angeli, A. Krivska, S. Garavaglia, L. Di Matteo, M. Vellucci, F. Napoli, P. Petrolini, Sergio Briguglio, B. Angelini, Gregorio Vlad, B. Tilia, F. Gravanti, Giovanni Grossetti, G. Apruzzese, F. Belli, E. Di Ferdinando, Luca Boncagni, A. Cardinali, S. Di Giovenale, V Zanza, L. Gabellieri, G. Maddaluno, C. Di Troia, Gustavo Granucci, Silvio Ceccuzzi, E. Alessi, F. Iannone, G. Mazzitelli, M. Panella, A. Romano, B. Viola, G. Giacomi, Giovanni Grosso, V. Piergotti, G. Calabrò, A. Bertocchi, S. Podda, Gian Luca Ravera, C. Centioli, L. Amicucci, S. Cirant, C. Torelli, B. Raspante, Aldo Pizzuto, A. Grosso, V. Vitale, Angelo A. Tuccillo, O. D'Arcangelo, D. Pacella, V. Pericoli-Ridolfini, Alessandro Bruschi, E. Barbato, M. Zerbini, C. Castaldo, C. Marchetto, M. Marinucci, M. Mezzacappa, G. Pucella, A. Milovanov, M.L. Apicella, P. Cefali, M. Lontano, A. Botrugno, R. Cesario, C. Mazzotta, Carlo Sozzi, M. Aquilini, C. Cianfarani, A. Pensa, R. De Angelis, G.A. Moro, Francesco Mirizzi, E. Lazzaro, Daniele Marocco, D. Zannetti, V. Fusco, D. Minelli, O. Tudisco, G. Fogaccia, G. Artaserse, F. Crisanti, Fulvio Zonca, P. Buratti, Basilio Esposito, F.P. Orsitto, L. Panaccione, V. Mellera, Zannetti, D., Vellucci, M., Tulli, R., Torelli, C., Tilia, B., Sibio, A., Rocchi, G., Raspante, B., Piergotti, V., Petrolini, P., Pensa, A., Mezzacappa, M., Grosso, A., Gravanti, F., Giacomi, G., Di Giovenale, S., Di Ferdinando, E., Cefali, P., Aquilini, M., Zonca, F., Zerbini, M., Zanza, V., Vlad, G., Vitale, V., Viola, B., Tudisco, O., Tuccillo, A. A., Romano, A., Ravera, G., Ramogida, G., Pucella, G., Pizzuto, A., Podda, S., Pericoli-Ridolfini, V., Panella, M., Panaccione, L., Pacella, D., Orsitto, F. P., Mirizzi, F. C., Milovanov, A., Mazzotta, C., Mazzitelli, G., Marocco, D., Marinucci, M., Maddaluno, G., Kroegler, H., Krivska, A., Iannone, F., Giovannozzi, E., Gabellieri, L., Frigione, D., Fogaccia, G., Esposito, B., Di Troia, C., Di Matteo, L., De Angelis, R., Crisanti, F., Cirant, S., Cianfarani, C., Cesario, R., Centioli, C., Castaldo, C., Cardinali, A., Calabrò, G., Bruschi, A., Briguglio, S., Botrugno, A., DE ANGELIS, Riccardo, Calabro, G., Apicella, M. L., and Buratti, P.

Subjects
Physics, Nuclear and High Energy Physics, Safety factor, Cyclotron, Plasma, Sawtooth wave, Condensed Matter Physics, Electron cyclotron resonance, Computational physics, law.invention, Physics::Plasma Physics, Modulation, law, ____, Electric current, Doppler broadening
Abstract

Since the 2010 IAEA-FEC Conference, FTU has exploited improvements in cleaning procedures and in the density control system to complete a systematic exploration of access to high-density conditions in a wide range of plasma currents and magnetic fields. The line-averaged densities at the disruptive limit increased more than linearly with the toroidal field, while no dependence on plasma current was found; in fact, the maximum density of 4.3 × 10 20 m-3 was reached at B = 8 T even at the minimum current of 0.5 MA, corresponding to twice the Greenwald limit. The lack of plasma current dependence was due to the increase in density peaking with the safety factor. Experiments with the 140 GHz electron cyclotron resonance heating (ECRH) system were focused on the sawtooth (ST) period control and on the commissioning of a new launcher with real-time steering capability that will act as the front-end actuator of a real-time system for ST period control and tearing mode stabilization. Various ECRH and electron cyclotron current-drive modulation schemes were used; with the fastest one, the ST period synchronized with an 8 ms modulation period. The observed period variations were simulated using the JETTO code with a critical shear model for the crash trigger. The new launcher was of the plug-in type, allowing quick insertion and connection to the transmission line. Both beam characteristics and steering speed were in line with design expectation. Experimental results on the connection between improved coupling of lower hybrid waves in high-density plasmas and reduced wave spectral broadening were interpreted by fully kinetic, non-linear model calculations. A dual-frequency, time-of-flight diagnostic for the measurement of density profiles was developed and successfully tested. Fishbone-like instabilities driven by energetic electrons were simulated by the hybrid MHD-gyrokinetic XHMGC code. © 2013 IAEA, Vienna.

47. MHD activity in FTU plasmas with reversed magnetic shear

Author

C. Centioli, V. Pericoli Ridolfini, S. Podda, Marco Ciotti, S. Ciattaglia, A Mancuso, G. Maddaluno, O. Tudisco, M. Grolli, Gregorio Vlad, D. Frigione, G. Buceti, Angelo A. Tuccillo, F. Alladio, G. Maffia, Alessandro Simonetto, Carlo Sozzi, E. Barbato, A. Bertocchi, B. Angelini, D Pacella, P. Buratti, R. De Angelis, G. Apruzzese, M.L. Apicella, G Gatti, H. Kroegler, M Panella, G. Bracco, F. Santini, V Vitale, F. P. Orsitto, L. Panaccione, P Micozzi, S. Sternini, V Zanza, F Valente, B Esposito, L Gabellieri, L. Acitelli, F. Crisanti, L. Pieroni, M. Leigheb, Francesco Mirizzi, R. Cesario, Alessandro Bruschi, A Imparato, V Cocilovo, G. Mazzitelli, C. Gourlan, S Cirant, E. Giovannozzi, F. De Marco, M. Marinucci, Gustavo Granucci, G.B. Righetti, S. E. Segre, L. Lovisetto, M. Zerbini, A. Cardinali, M. Sassi, and Francesco Romanelli

Subjects
Physics, Resistive touchscreen, Safety factor, Tokamak, Plasma, Condensed Matter Physics, law.invention, Shear (sheet metal), ___, Nuclear Energy and Engineering, Physics::Plasma Physics, law, Excited state, Physics::Space Physics, Magnetohydrodynamics, Atomic physics, Excitation
Abstract

The MHD activity of plasma configurations with reversed magnetic shear has been investigated on the FTU tokamak. In the presence of pairs of surfaces with the same rational value q = m/n of the safety factor, double-tearing modes are excited which give rise in most cases to bursts of sawtooth-like profile rearrangements. More stable regimes have also been found, in which the activity is dominated by rotating saturated modes. In a particular case with q(0) approximate to 2.8 and q(min) approximate to 2.5 a discharge without any detectable MHD activity during the current flat-top has been obtained. In high-temperature regimes (T-e x 8 keV at n(e) approximate to 0.8 x 10(20) m(-3)), an irregular activity has been detected near the plasma centre which could be due to the excitation of resistive interchange modes.

48. Overview of the FTU results.

Author

G. Pucella, E. Alessi, L. Amicucci, B. Angelini, M.L. Apicella, G. Apruzzese, G. Artaserse, F. Belli, W. Bin, L. Boncagni, A. Botrugno, S. Briguglio, A. Bruschi, P. Buratti, G. Calabrò, M. Cappelli, and A. Cardinali

Subjects
ELECTRONS, ELECTRIC fields, PLASMA currents, ELECTRON cyclotron resonance heating, MAGNETICS
Abstract

Experiments on runaway electrons have been performed for the determination of the critical electric field for runaway generation. A large database of post-disruption runaway beams has been analyzed in order to identify linear dynamical models for new position and current runaway beam controllers, and experiments of electron cyclotron assisted plasma start-up have shown the presence of runaway electrons also below the expected electric field threshold, indicating that the radio-frequency power acts as seeding for fast electrons. A linear micro-stability analysis of neon-doped pulses has been carried out to investigate the mechanisms leading to the observed density peaking. A study of the ion drift effects on the MARFE instability has been performed and the peaking of density profile in the high density regime has been well reproduced using a thermo-diffusive pinch in the particle transport equation. The study of the density limit performed in the past has been extended towards lower values of toroidal magnetic field and plasma current. The analysis of the linear stability of the 2/1 tearing mode observed in high density plasmas has highlighted a destabilization with increasing peaking of the current profile during the density ramp-up, while the final phase of the mode temporal evolution is characterized by limit cycles on the amplitude/frequency plane. A liquid lithium limiter with thermal load capability up to 10 MW m−2 has been tested. The pulse duration has been extended up to 4.5 s and elongated configurations have been obtained for 3.5 s, with the X-point just outside the plasma chamber. A W/Fe sample has been exposed in the scrape-off layer in order to study the sputtering of Fe and the W enrichment of the surface layer. Dusts have been collected and analyzed, showing that the metallic population exhibits a high fraction of magnetic grains. A new diagnostic for in-flight runaway electron studies has allowed the image and the visible/infrared spectrum of the forward and backward synchrotron radiation to be provided simultaneously. A fast infrared camera for thermo-graphic analysis has provided the pattern of the toroidal limiter heating by disruption heat loads, and a triple-GEM detector has been tested for soft x-ray diagnostics. The collective Thomson scattering diagnostic has been upgraded and used for investigations on parametric decay instability excitation by electron cyclotron beams correlated with magnetic islands, and new capabilities of the Cherenkov probe have been explored in the presence of beta-induced Alfvén eigenmodes associated to high amplitude magnetic islands. [ABSTRACT FROM AUTHOR]

Published
2017
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49. Overview of the FTU results.

Author

G. Pucella, E. Alessi, L. Amicucci, B. Angelini, M.L. Apicella, G. Apruzzese, G. Artaserse, E. Barbato, F. Belli, A. Bertocchi, W. Bin, L. Boncagni, A. Botrugno, S. Briguglio, A. Bruschi, P. Buratti, G. Calabrò, A. Cardinali, C. Castaldo, and F. Causa

Subjects
ELECTRON cyclotron resonance heating, FUSION reactors, PLASMA heating, CYCLOTRON resonance, SYNCHROTRON radiation, NUCLEAR fusion
Abstract

Since the 2012 IAEA-FEC Conference, FTU operations have been largely devoted to runaway electrons generation and control, to the exploitation of the 140 GHz electron cyclotron (EC) system and to liquid metal limiter elements. Experiments on runaway electrons have shown that the measured threshold electric field for their generation is larger than predicted by collisional theory and can be justified considering synchrotron radiation losses. A new runaway electrons control algorithm was developed and tested in presence of a runaway current plateau, allowing to minimize the interactions with plasma facing components and safely shut down the discharges. The experimental sessions with 140 GHz EC system have been mainly devoted to experiments on real-time control of magnetohydrodynamic (MHD) instabilities using the new EC launcher with fast steering capability. Experiments with central EC injection have shown the onset of 3/2 and 2/1 tearing modes, while EC assisted breakdown experiments have been focused on ITER start-up issues, exploring the polarization conversion at reflection from inner wall and the capability to assure plasma start-up even in presence of a large stray magnetic field. A new actively cooled lithium limiter has been installed and tested. The lithium limiter was inserted in the scrape-off layer, without any damage to the limiter surface. First elongated FTU plasmas with EC additional heating were obtained with the new cooled limiter. Density peaking and controlled MHD activity driven by neon injection were investigated at different plasma parameters. A full real-time algorithm for disruption prediction, based on MHD activity signals from Mirnov coils, was developed exploiting a large database of disruptions. Reciprocating Langmuir probes were used to measure the heat flux e-folding length in the scrape-off layer, with the plasma kept to lay on thea internal limiter to resemble the ITER start-up phase. New diagnostics were successfully installed and tested, as a diamond probe to detect Cherenkov radiation produced by fast electrons and a gamma camera for runaway electrons studies. Laser induced breakdown spectroscopy measurements were performed under vacuum and with toroidal magnetic field, so demonstrating their capability to provide useful information on the surface elemental composition and fuel retention in present and future tokamaks, such as ITER. [ABSTRACT FROM AUTHOR]

Published
2015
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50. Fully Automated Postlumpectomy Breast Margin Assessment Utilizing Convolutional Neural Network Based Optical Coherence Tomography Image Classification Method.

Author

Mojahed D, Ha RS, Chang P, Gan Y, Yao X, Angelini B, Hibshoosh H, Taback B, and Hendon CP

Subjects
Algorithms, Breast Neoplasms diagnostic imaging, Female, Humans, Margins of Excision, Postoperative Period, Breast diagnostic imaging, Breast Neoplasms pathology, Breast Neoplasms surgery, Image Processing, Computer-Assisted methods, Magnetic Resonance Imaging methods, Mastectomy, Segmental methods, Neural Networks, Computer, Tomography, Optical Coherence methods
Abstract

Background: The purpose of this study was to develop a deep learning classification approach to distinguish cancerous from noncancerous regions within optical coherence tomography (OCT) images of breast tissue for potential use in an intraoperative setting for margin assessment., Methods: A custom ultrahigh-resolution OCT (UHR-OCT) system with an axial resolution of 2.7 μm and a lateral resolution of 5.5 μm was used in this study. The algorithm used an A-scan-based classification scheme and the convolutional neural network (CNN) was implemented using an 11-layer architecture consisting of serial 3 × 3 convolution kernels. Four tissue types were classified, including adipose, stroma, ductal carcinoma in situ, and invasive ductal carcinoma., Results: The binary classification of cancer versus noncancer with the proposed CNN achieved 94% accuracy, 96% sensitivity, and 92% specificity. The mean five-fold validation F1 score was highest for invasive ductal carcinoma (mean standard deviation, 0.89 ± 0.09) and adipose (0.79 ± 0.17), followed by stroma (0.74 ± 0.18), and ductal carcinoma in situ (0.65 ± 0.15)., Conclusion: It is feasible to use CNN based algorithm to accurately distinguish cancerous regions in OCT images. This fully automated method can overcome limitations of manual interpretation including interobserver variability and speed of interpretation and may enable real-time intraoperative margin assessment., (Copyright © 2019 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Published
2020
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