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8. Current sheet fragmentation following magnetic reconnection in RFP plasmas

Author

Poedts, S, Fajardo, M, Giruzzi, G, Gans, T, Vennekens, N, Mantica, P, Cordaro, L, Zuin, M, Momo, B, Martines, E, Spolaore, M, Auriemma, F, Cavazzana, R, De Masi, G, Scarin, P, Spagnolo, S, Vianello, N, Cester, D, Stevanato, L, Isliker, H, Vlahos, L, Schneider, W, Cordaro L, Zuin M, Momo B, Martines E, Spolaore M, Auriemma F, Cavazzana R, De Masi G, Scarin P, Spagnolo S, Vianello N, Cester D, Stevanato L, Isliker H, Vlahos L, Schneider W, Poedts, S, Fajardo, M, Giruzzi, G, Gans, T, Vennekens, N, Mantica, P, Cordaro, L, Zuin, M, Momo, B, Martines, E, Spolaore, M, Auriemma, F, Cavazzana, R, De Masi, G, Scarin, P, Spagnolo, S, Vianello, N, Cester, D, Stevanato, L, Isliker, H, Vlahos, L, Schneider, W, Cordaro L, Zuin M, Momo B, Martines E, Spolaore M, Auriemma F, Cavazzana R, De Masi G, Scarin P, Spagnolo S, Vianello N, Cester D, Stevanato L, Isliker H, Vlahos L, and Schneider W

Published
2016

9. Current sheet fragmentation following magnetic reconnection in RFP plasmas

Author

Luigi Cordaro, Zuin, M., Momo, B., Martines, E., Spolaore, M., Auriemma, F., Cavazzana, R., Masi, G., Scarin, P., Spagnolo, S., Vianello, N., Cester, D., Stevanato, L., Isliker, H., Vlahos, L., Schneider, W., Poedts, S, Fajardo, M, Giruzzi, G, Gans, T, Vennekens, N, Mantica, P, Cordaro, L, Zuin, M, Momo, B, Martines, E, Spolaore, M, Auriemma, F, Cavazzana, R, De Masi, G, Scarin, P, Spagnolo, S, Vianello, N, Cester, D, Stevanato, L, Isliker, H, Vlahos, L, and Schneider, W

Subjects
RFX-mod, magnetic reconnection, current sheet, Atomic and Molecular Physics, RFP, reversed field pinch, and Optics, Atomic and Molecular Physics, and Optics
Published
2016

10. Characterization of particle dynamics and magnetic reconnection in the RFX-mod plasmas

Author

Bingham, R, Goncalves, B, Suttrop, W, Foest, R, Silva, C, Coelho, R, McClements, K, Atzeni, S, Zuin, M, Stevanato, L, Martines, E, Auriemma, F, Momo, B, Cavazzana, R, De Masi, G, Gonzalez, W, Lorenzini, R, Scarin, P, Spagnolo, S, Spolaore, M, Vianello, N, Schneider, W, Cester, D, Nebbia, G, Sajo-Bohus, L, Viesti, G, Zuin M, Stevanato L, Martines E, Auriemma F, Momo B, Cavazzana R, De Masi G, Gonzalez W, Lorenzini R, Scarin P, Spagnolo S, Spolaore M, Vianello N, Schneider W, Cester D, Nebbia G, Sajo-Bohus L, Viesti G, Bingham, R, Goncalves, B, Suttrop, W, Foest, R, Silva, C, Coelho, R, McClements, K, Atzeni, S, Zuin, M, Stevanato, L, Martines, E, Auriemma, F, Momo, B, Cavazzana, R, De Masi, G, Gonzalez, W, Lorenzini, R, Scarin, P, Spagnolo, S, Spolaore, M, Vianello, N, Schneider, W, Cester, D, Nebbia, G, Sajo-Bohus, L, Viesti, G, Zuin M, Stevanato L, Martines E, Auriemma F, Momo B, Cavazzana R, De Masi G, Gonzalez W, Lorenzini R, Scarin P, Spagnolo S, Spolaore M, Vianello N, Schneider W, Cester D, Nebbia G, Sajo-Bohus L, and Viesti G

Published
2015

11. Overview of the RFX-mod contribution to the international Fusion Science Program

Author

Puiatti, M, Dal Bello, S, Marrelli, L, Martin, P, Agostinetti, P, Agostini, M, Antoni, V, Auriemma, F, Barbisan, M, Barbui, T, Baruzzo, M, Battistella, M, Belli, F, Bettini, P, Bigi, M, Bilel, R, Boldrin, M, Bolzonella, T, Bonfiglio, D, Brombin, M, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cester, D, Chacon, L, Chapman, B, Chitarin, G, Ciaccio, G, Cooper, W, Dalla Palma, M, Deambrosis, S, Delogu, R, De Lorenzi, A, De Masi, G, Dong, J, Escande, D, Esposito, B, Fassina, A, Fellin, F, Ferro, A, Finotti, C, Franz, P, Frassinetti, L, Palumbo, M, Gaio, E, Ghezzi, F, Giudicotti, L, Gnesotto, F, Gobbin, M, Gonzales, W, Grando, L, Guo, S, Hanson, J, Hirshman, S, Innocente, P, Jackson, J, Kiyama, S, Komm, M, Laguardia, L, Li, C, Liu, S, Liu, Y, Lorenzini, R, Luce, T, Luchetta, A, Maistrello, A, Manduchi, G, Mansfield, D, Marchiori, G, Marconato, N, Marocco, D, Marcuzzi, D, Martines, E, Martini, S, Matsunaga, G, Mazzitelli, G, Miorin, E, Momo, B, Moresco, M, Okabayashi, M, Olofsson, E, Paccagnella, R, Patel, N, Pavei, M, Peruzzo, S, Pilan, N, Pigatto, L, Piovan, R, Piovesan, P, Piron, C, Piron, L, Predebon, I, Rea, C, Recchia, M, Rigato, V, Rizzolo, A, Roquemore, A, Rostagni, G, Ruset, C, Ruzzon, A, Sajo-Bohus, L, Sakakita, H, Sanchez, R, Sarff, J, Sartori, E, Sattin, F, Scaggion, A, Scarin, P, Schmitz, O, Sonato, P, Spada, E, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Stevanato, L, Takechi, M, Taliercio, C, Terranova, D, Trevisan, G, Urso, G, Valente, M, Valisa, M, Veranda, M, Vianello, N, Viesti, G, Villone, F, Vincenzi, P, Visona', N, Wang, Z, White, R, Xanthopoulos, P, Xu, X, Yanovskiy, V, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zuin, M, Puiatti M E, Dal Bello S, Marrelli L, Martin P, Agostinetti P, Agostini M, Antoni V, Auriemma F, Barbisan M, Barbui T, Baruzzo M, Battistella M, Belli F, Bettini P, Bigi M, Bilel R, Boldrin M, Bolzonella T, Bonfiglio D, Brombin M, Buffa A, Canton A, Cappello S, Carraro L, Cavazzana R, Cester D, Chacon L, Chapman B E, Chitarin G, Ciaccio G, Cooper W A, Dalla Palma M, Deambrosis S, Delogu R, De Lorenzi A, De Masi G, Dong J Q, Escande D F, Esposito B, Fassina A, Fellin F, Ferro A, Finotti C, Franz P, Frassinetti L, Palumbo M Furno, Gaio E, Ghezzi F, Giudicotti L, Gnesotto F, Gobbin M, Gonzales W A, Grando L, Guo S C, Hanson J D, Hirshman S P, Innocente P, Jackson J L, Kiyama S, Komm M, Laguardia L, Li C, Liu S F, Liu Y Q, Lorenzini R, Luce T C, Luchetta A, Maistrello A, Manduchi G, Mansfield D K, Marchiori G, Marconato N, Marocco D, Marcuzzi D, Martines E, Martini S, Matsunaga G, Mazzitelli G, Miorin E, Momo B, Moresco M, Okabayashi M, Olofsson E, Paccagnella R, Patel N, Pavei M, Peruzzo S, Pilan N, Pigatto L, Piovan R, Piovesan P, Piron C, Piron L, Predebon I, Rea C, Recchia M, Rigato V, Rizzolo A, Roquemore A L, Rostagni G, Ruset C, Ruzzon A, Sajo-Bohus L, Sakakita H, Sanchez R, Sarff J S, Sartori E, Sattin F, Scaggion A, Scarin P, Schmitz O, Sonato P, Spada E, Spagnolo S, Spolaore M, Spong D A, Spizzo G, Stevanato L, Takechi M, Taliercio C, Terranova D, Trevisan G L, Urso G, Valente M, Valisa M, Veranda M, Vianello N, Viesti G, Villone F, Vincenzi P, Visona' N, Wang Z R, White R B, Xanthopoulos P, Xu X Y, Yanovskiy V, Zamengo A, Zanca P, Zaniol B, Zanotto L, Zilli E, Zuin M, Puiatti, M, Dal Bello, S, Marrelli, L, Martin, P, Agostinetti, P, Agostini, M, Antoni, V, Auriemma, F, Barbisan, M, Barbui, T, Baruzzo, M, Battistella, M, Belli, F, Bettini, P, Bigi, M, Bilel, R, Boldrin, M, Bolzonella, T, Bonfiglio, D, Brombin, M, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cester, D, Chacon, L, Chapman, B, Chitarin, G, Ciaccio, G, Cooper, W, Dalla Palma, M, Deambrosis, S, Delogu, R, De Lorenzi, A, De Masi, G, Dong, J, Escande, D, Esposito, B, Fassina, A, Fellin, F, Ferro, A, Finotti, C, Franz, P, Frassinetti, L, Palumbo, M, Gaio, E, Ghezzi, F, Giudicotti, L, Gnesotto, F, Gobbin, M, Gonzales, W, Grando, L, Guo, S, Hanson, J, Hirshman, S, Innocente, P, Jackson, J, Kiyama, S, Komm, M, Laguardia, L, Li, C, Liu, S, Liu, Y, Lorenzini, R, Luce, T, Luchetta, A, Maistrello, A, Manduchi, G, Mansfield, D, Marchiori, G, Marconato, N, Marocco, D, Marcuzzi, D, Martines, E, Martini, S, Matsunaga, G, Mazzitelli, G, Miorin, E, Momo, B, Moresco, M, Okabayashi, M, Olofsson, E, Paccagnella, R, Patel, N, Pavei, M, Peruzzo, S, Pilan, N, Pigatto, L, Piovan, R, Piovesan, P, Piron, C, Piron, L, Predebon, I, Rea, C, Recchia, M, Rigato, V, Rizzolo, A, Roquemore, A, Rostagni, G, Ruset, C, Ruzzon, A, Sajo-Bohus, L, Sakakita, H, Sanchez, R, Sarff, J, Sartori, E, Sattin, F, Scaggion, A, Scarin, P, Schmitz, O, Sonato, P, Spada, E, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Stevanato, L, Takechi, M, Taliercio, C, Terranova, D, Trevisan, G, Urso, G, Valente, M, Valisa, M, Veranda, M, Vianello, N, Viesti, G, Villone, F, Vincenzi, P, Visona', N, Wang, Z, White, R, Xanthopoulos, P, Xu, X, Yanovskiy, V, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zuin, M, Puiatti M E, Dal Bello S, Marrelli L, Martin P, Agostinetti P, Agostini M, Antoni V, Auriemma F, Barbisan M, Barbui T, Baruzzo M, Battistella M, Belli F, Bettini P, Bigi M, Bilel R, Boldrin M, Bolzonella T, Bonfiglio D, Brombin M, Buffa A, Canton A, Cappello S, Carraro L, Cavazzana R, Cester D, Chacon L, Chapman B E, Chitarin G, Ciaccio G, Cooper W A, Dalla Palma M, Deambrosis S, Delogu R, De Lorenzi A, De Masi G, Dong J Q, Escande D F, Esposito B, Fassina A, Fellin F, Ferro A, Finotti C, Franz P, Frassinetti L, Palumbo M Furno, Gaio E, Ghezzi F, Giudicotti L, Gnesotto F, Gobbin M, Gonzales W A, Grando L, Guo S C, Hanson J D, Hirshman S P, Innocente P, Jackson J L, Kiyama S, Komm M, Laguardia L, Li C, Liu S F, Liu Y Q, Lorenzini R, Luce T C, Luchetta A, Maistrello A, Manduchi G, Mansfield D K, Marchiori G, Marconato N, Marocco D, Marcuzzi D, Martines E, Martini S, Matsunaga G, Mazzitelli G, Miorin E, Momo B, Moresco M, Okabayashi M, Olofsson E, Paccagnella R, Patel N, Pavei M, Peruzzo S, Pilan N, Pigatto L, Piovan R, Piovesan P, Piron C, Piron L, Predebon I, Rea C, Recchia M, Rigato V, Rizzolo A, Roquemore A L, Rostagni G, Ruset C, Ruzzon A, Sajo-Bohus L, Sakakita H, Sanchez R, Sarff J S, Sartori E, Sattin F, Scaggion A, Scarin P, Schmitz O, Sonato P, Spada E, Spagnolo S, Spolaore M, Spong D A, Spizzo G, Stevanato L, Takechi M, Taliercio C, Terranova D, Trevisan G L, Urso G, Valente M, Valisa M, Veranda M, Vianello N, Viesti G, Villone F, Vincenzi P, Visona' N, Wang Z R, White R B, Xanthopoulos P, Xu X Y, Yanovskiy V, Zamengo A, Zanca P, Zaniol B, Zanotto L, Zilli E, and Zuin M

Abstract

The RFX-mod device is operated both as a reversed field pinch (RFP), where advanced regimes featuring helical shape develop, and as a tokamak. Due to its flexibility, RFX-mod is contributing to the solution of key issues in the roadmap to ITER and DEMO, including MHD instability control, internal transport barriers, edge transport and turbulence, isotopic effect, high density limit and three-dimensional (3D) non-linear MHD modelling. This paper reports recent advancements in the understanding of the self-organized helical states, featuring a strong electron transport barrier, in the RFP configuration; the physical mechanism driving the residual transport at the barrier has been investigated. Following the first experiments with deuterium as the filling gas, new results concerning the isotope effect in the RFP are discussed. Studies on the high density limit show that in the RFP it is related to a toroidal particle accumulation due to the onset of a convective cell. In the tokamak configuration, q(a) regimes down to q(a) = 1.2 have been pioneered, with (2,1) tearing mode (TM) mitigated and (2,1) resistive wall mode (RWM) stabilized: the control of such modes can be obtained both by poloidal and radial sensors. Progress has been made in the avoidance of disruptions due to the (2,1) TM by applying q(a) control, and on the general issue of error field control. The effect of externally applied 3D fields on plasma flow and edge turbulence, sawtooth control and runaway electron decorrelation has been analysed. The experimental program is supported by substantial theoretical activity: 3D non-linear visco-resistive MHD and non-local transport modelling have been advanced; RWMs have been studied by a toroidal MHD kinetic hybrid stability code.

Published
2015

12. Characterization of fast ion dynamics and neutron production in RFX-mod

Author

Zuin M., Stevanato L., Martines E., Auriemma F., Momo B., Cavazzana R., De Masi G., Gobbin M., Gonzalez W., Lorenzini R., Piovan R., Puiatti M.E., Scarin P., Spagnolo S., Spolaore M., Valisa M., Vianello N., Schneider W., Cester D., Nebbia G., Sajo-Bohus L., and Viesti G.

Subjects
RFX-Mod, Physics::Plasma Physics, Astrophysics::High Energy Astrophysical Phenomena, Nuclear Theory, neutron production, fast ion dynamics, Nuclear Experiment
Abstract

Characterization of fast ion dynamics and neutron production in RFX-mod

Published
2017

13. Characterization of particle dynamics and magnetic reconnection in the RFX-mod plasmas

Author

Zuin, M., Stevanato, L., Emilio Martines, Auriemma, F., Momo, B., Cavazzana, R., Masi, G., Gonzalez, W., Lorenzini, R., Scarin, P., Spagnolo, S., Spolaore, M., Vianello, N., Schneider, W., Cester, D., Nebbia, G., Sajo-Bohus, L., Viesti, G., Bingham, R, Goncalves, B, Suttrop, W, Foest, R, Silva, C, Coelho, R, McClements, K, Atzeni, S, Zuin, M, Stevanato, L, Martines, E, Auriemma, F, Momo, B, Cavazzana, R, De Masi, G, Gonzalez, W, Lorenzini, R, Scarin, P, Spagnolo, S, Spolaore, M, Vianello, N, Schneider, W, Cester, D, Nebbia, G, Sajo-Bohus, L, and Viesti, G

Subjects
RFX-mod, Physics::Plasma Physics, Astrophysics::High Energy Astrophysical Phenomena, Atomic and Molecular Physics, magnetic reconnection, Physics::Space Physics, RFP, reversed field pinch, and Optics, Atomic and Molecular Physics, and Optics
Abstract

An experimental analysis of particle dynamics is presented in both tokamak and reversed-field pinch (RFP) Deuterium plasmas produced in the RFX-mod device. Particular attention is dedicated to effect of magnetic reconnection processes occurring spontaneously in the plasma. The diagnostics is made of a Neutral Particle Analyzer (NPA) and of a couple of neutron and gamma-ray detectors. The NPA can resolve the energy distribution of the neutral atoms produced by charge-exchange processes and exiting the plasma on the low field side on equatorial plane of the machine on 11 energy channels, being the energy and mass dispersion produced by a E//B combination. Neutron and gamma-ray fluxes are measured by means of 2 scintillators (EJ-301 liquid and NaI(Tl)) coupled to flat-panel photomultipliers, suitable for operation under magnetic fields. The production of neutrons and gamma rays in RFP plasmas is found to be strongly influenced by the Ohmic input power, with a threshold value of about 1.2MA in terms of plasma current level. Below such current value a low rate of gamma rays and almost no neutrons are detected. Neutral Deuterium atoms fluxes, neutron and gamma productions are strongly determined by the MHD activity measured in the plasma. In particular, a bursty behavior of neutron yields, correlated to the spontaneous magnetic reconnection events, occurring almost cyclically in the RFP plasmas are observed. Magnetic reconnection also modifies the energy distribution of neutral atoms having impact on both the Maxwellian component and on the observed higher energy tail. This is true also in tokamak plasmas during the sawtoothing activity mostly seen in low q(a) condition. The role of particle acceleration and ion heating during such events is discussed.

Published
2015

14. Overview of the RFX-mod fusion science activity

Author

Zuin, M., Dal Bello, S., Marrelli, L., Puiatti, M. E., 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. A., Cordaro, L., Palma, M. Dalla, Deambrosis, S., Delogu, R., De Lorenzi, A., De Masi, G., Dong, J. Q., Escande, D. F., Fassina, A., Felici, F., Ferro, A., Finotti, C., Franz, P., Frassinetti, Lorenzo, Gaio, E., Ghezzi, F., Giudicotti, L., Gnesotto, F., Gobbin, M., Gonzalez, W. A., Grando, L., Guo, S. C., Hanson, J. D., Hirshman, S. P., Innocente, P., Jackson, J. L., Kiyama, S., Komm, M., Kudlacek, O., Laguardia, L., Li, C., Liu, B., Liu, S. F., Liu, Y. Q., Lopez-Bruna, D., Lorenzini, R., Luce, T. C., Luchetta, A., Maistrello, A., Manduchi, G., Mansfield, D. K., 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., Sajo-Bohus, L., Sakakita, H., Sanchez, R., Sarff, J. S., Sattin, F., Scarin, P., Schmitz, O., Schneider, W., Siragusa, M., Sonato, P., Spada, E., Spagnolo, S., Spolaore, M., Spong, D. A., 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., Visona, N., White, R. B., Xanthopoulos, P., Xu, X. Y., Yanovskiy, V., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zhang, Y., Zilli, E., Zuin, M., Dal Bello, S., Marrelli, L., Puiatti, M. E., 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. A., Cordaro, L., Palma, M. Dalla, Deambrosis, S., Delogu, R., De Lorenzi, A., De Masi, G., Dong, J. Q., Escande, D. F., Fassina, A., Felici, F., Ferro, A., Finotti, C., Franz, P., Frassinetti, Lorenzo, Gaio, E., Ghezzi, F., Giudicotti, L., Gnesotto, F., Gobbin, M., Gonzalez, W. A., Grando, L., Guo, S. C., Hanson, J. D., Hirshman, S. P., Innocente, P., Jackson, J. L., Kiyama, S., Komm, M., Kudlacek, O., Laguardia, L., Li, C., Liu, B., Liu, S. F., Liu, Y. Q., Lopez-Bruna, D., Lorenzini, R., Luce, T. C., Luchetta, A., Maistrello, A., Manduchi, G., Mansfield, D. K., 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., Sajo-Bohus, L., Sakakita, H., Sanchez, R., Sarff, J. S., Sattin, F., Scarin, P., Schmitz, O., Schneider, W., Siragusa, M., Sonato, P., Spada, E., Spagnolo, S., Spolaore, M., Spong, D. A., 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., Visona, N., White, R. B., Xanthopoulos, P., Xu, X. Y., Yanovskiy, V., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zhang, Y., and Zilli, E.

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., QC 20170802

Published
2017
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15. Overview of the RFX-mod fusion science activity

Author

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, Zilli, E, ZUIN, MATTEO, DAL BELLO, SILVIA, MARRELLI, LIONELLO, Puiatti, M. E., AGOSTINETTI, PIERO, AGOSTINI, MATTEO, ANTONI, VANNI, AURIEMMA, FULVIO, BARBISAN, MARCO, BARBUI, TULLIO, BARUZZO, MATTEO, Belli, F., BETTINI, PAOLO, Bigi, M., Bilel, R., Boldrin, M., BOLZONELLA, TOMMASO, BONFIGLIO, DANIELE, BROMBIN, MATTEO, BUFFA, ANTONIO, BUSTREO, CHIARA, CANTON, ALESSANDRA MARIA, CAPPELLO, SUSANNA, Carraro, L., Cavazzana, R., CESTER, DAVIDE, Chacon, L., CHITARIN, GIUSEPPE, Cooper, W. A., CORDARO, LUIGI, DALLA PALMA, MAURO, DEAMBROSIS, SILVIA MARIA, Delogu, R., De Lorenzi, A., DE MASI, GIANLUCA, Dong, J. Q., Escande, D. F., FASSINA, ALESSANDRO, Felici, F., Ferro, A., FINOTTI, CLAUDIO, Franz, P., FRASSINETTI, LORENZO, Gaio, E., GHEZZI, FEDERICO, GIUDICOTTI, LEONARDO, GNESOTTO, FRANCESCO, GOBBIN, MARCO, GONZALEZ, WINDER ALEXANDER, GRANDO, LUCA, Guo, S. C., Hanson, J. D., Hirshman, S. P., Innocente, P., Jackson, J. L., Kiyama, S., Komm, M., KUDLACEK, ONDREJ, LAGUARDIA, ANNA LUCIA, Li, C., Liu, B., Liu, S. F., Liu, Y. Q., López Bruna, D., Lorenzini, R., Luce, T. C., LUCHETTA, ADRIANO FRANCESCO, MAISTRELLO, ALBERTO, MANDUCHI, GABRIELE, Mansfield, D. K., Marchiori, G., MARCONATO, NICOLO', Marcuzzi, D., MARTIN, PIERO, MARTINES, EMILIO, MARTINI, STEFANO, Mazzitelli, G., Mccormack, O., Miorin, E., MOMO, BARBARA, MORESCO, MAURIZIO, 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. S., Sattin, F., Scarin, P., Schmitz, O., Schneider, W., Siragusa, M., Sonato, P., Spada, E., Spagnolo, S., Spolaore, M., Spong, D. A., 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. B., Xanthopoulos, P., Xu, X. Y., Yanovskiy, V., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zhang, Y., Zilli, E., 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, Zilli, E, ZUIN, MATTEO, DAL BELLO, SILVIA, MARRELLI, LIONELLO, Puiatti, M. E., AGOSTINETTI, PIERO, AGOSTINI, MATTEO, ANTONI, VANNI, AURIEMMA, FULVIO, BARBISAN, MARCO, BARBUI, TULLIO, BARUZZO, MATTEO, Belli, F., BETTINI, PAOLO, Bigi, M., Bilel, R., Boldrin, M., BOLZONELLA, TOMMASO, BONFIGLIO, DANIELE, BROMBIN, MATTEO, BUFFA, ANTONIO, BUSTREO, CHIARA, CANTON, ALESSANDRA MARIA, CAPPELLO, SUSANNA, Carraro, L., Cavazzana, R., CESTER, DAVIDE, Chacon, L., CHITARIN, GIUSEPPE, Cooper, W. A., CORDARO, LUIGI, DALLA PALMA, MAURO, DEAMBROSIS, SILVIA MARIA, Delogu, R., De Lorenzi, A., DE MASI, GIANLUCA, Dong, J. Q., Escande, D. F., FASSINA, ALESSANDRO, Felici, F., Ferro, A., FINOTTI, CLAUDIO, Franz, P., FRASSINETTI, LORENZO, Gaio, E., GHEZZI, FEDERICO, GIUDICOTTI, LEONARDO, GNESOTTO, FRANCESCO, GOBBIN, MARCO, GONZALEZ, WINDER ALEXANDER, GRANDO, LUCA, Guo, S. C., Hanson, J. D., Hirshman, S. P., Innocente, P., Jackson, J. L., Kiyama, S., Komm, M., KUDLACEK, ONDREJ, LAGUARDIA, ANNA LUCIA, Li, C., Liu, B., Liu, S. F., Liu, Y. Q., López Bruna, D., Lorenzini, R., Luce, T. C., LUCHETTA, ADRIANO FRANCESCO, MAISTRELLO, ALBERTO, MANDUCHI, GABRIELE, Mansfield, D. K., Marchiori, G., MARCONATO, NICOLO', Marcuzzi, D., MARTIN, PIERO, MARTINES, EMILIO, MARTINI, STEFANO, Mazzitelli, G., Mccormack, O., Miorin, E., MOMO, BARBARA, MORESCO, MAURIZIO, 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. S., Sattin, F., Scarin, P., Schmitz, O., Schneider, W., Siragusa, M., Sonato, P., Spada, E., Spagnolo, S., Spolaore, M., Spong, D. A., 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. B., Xanthopoulos, P., Xu, X. Y., Yanovskiy, V., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zhang, Y., and Zilli, E.

Abstract

This paper reports the main recent results of the RFX-mod fusion science activity. The RFX-mod device is characterized by a unique exibility in terms of accessible magnetic con gurations. Axisymmetric and helically shaped reversed- eld 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 con gurations in between the two, the so-called ultra-low q ones, has been explored, with the aim of studying speci c 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 speci c 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 rst transitions to an improved con nement scenario in circular and D-shaped tokamak plasmas have been obtained thanks to an active modi cation of the edge electric eld through a polarized electrode. The experiments are supported by intense modeling with 3D MHD, gyrokinetic, guiding center and transport codes. Proposed modi cations 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 brie y presented.

Published
2017

16. Runaway electron mitigation by applied magnetic perturbations in RFX-mod tokamak plasmas

Author

Gobbin, M, Valisa, M, White, R, Cester, D, Marrelli, L, Nocente, M, Piovesan, P, Stevanato, L, Puiatti, M, Zuin, M, Zuin, M., NOCENTE, MASSIMO, Gobbin, M, Valisa, M, White, R, Cester, D, Marrelli, L, Nocente, M, Piovesan, P, Stevanato, L, Puiatti, M, Zuin, M, Zuin, M., and NOCENTE, MASSIMO

Abstract

Thanks to its advanced system for the control of magnetohydrodynamic modes, the RFXmod device run as a tokamak is particularly suited to the study of the possible impact on runaway electron (RE) de-confinement in response to applied magnetic perturbations. This paper shows that during the flat-top phase in RFX-mod discharges, with a plasma current of Ip∼150 kA and a low density (ne<1019 m-3), the amount of REs scales with the m = 2,n = 1 perturbation both in q(a) < 2 and q(a) > 2 plasmas. Similar results have also been obtained in post-disruption phases, but still with limited statistics. The mechanisms generating REs and the effect of magnetic perturbation (MP) on their confinement are interpreted by numerical simulations with the relativistic guiding center code ORBIT. The role played by different magnetic equilibria on the energy of REs and on their loss rates is investigated. ORBIT simulations indicate that RE-enhanced losses are associated with a raised level of stochasticity, the effect being more pronounced when the MP amplitude is higher and internally resonant

Published
2017

17. Neutron Production and Fast Particle Dynamics in Reversed-Field Pinch Plasmas for FFH

Author

Zuin M., Stevanato L., Martines E., Auriemma F., Momo B., Cavazzana R., De Masi G., Gobbin M., Gonzalez W., Lorenzini R., Piovan R., Puiatti M.E., Scarin P., Spagnolo S., Spolaore M., Valisa M., Vianello N., Schneider W., Cester D., Nebbia G., Sajo-Bohus L., and Viesti G.

Subjects
Physics::Plasma Physics, Physics::Space Physics
Abstract

An experimental study of neutron production and particle dynamics in Deuterium plasmas is presented in the RFX-mod device operated in reversed-field pinch (RFP) configuration. In the RFP, the toroidal magnetic field is one order of magnitude smaller than in a tokamak, and is mainly generated by currents flowing in the plasma itself, thus reducing the need for superconducting coils. This feature underlies the main potential advantage as a reactor concept of the RFP, namely the capability of achieving fusion conditions with purely ohmic heating in a much simpler and compact device. The present analysis is mainly based on data collected by means of a couple of neutron and gammaray detectors and of a neutral particle analyzer (NPA). The NPA resolves the energy distribution of the neutral atoms produced by charge-exchange processes, exiting the plasma on the low field side and on the equatorial plane of the machine. Energy and mass dispersion are produced by a combination of electrostatic and magnetic fields. Neutron and gamma-ray fluxes are measured by means of 2 scintillators (EJ-301 liquid and NaI(Tl)) coupled to flat-panel photomultipliers, suitable for operation in a noisy magnetic environment. The production of neutrons from D-D fusion reactions and gamma rays in RFP plasmas is found to be determined by the ohmic input power, with a threshold value of about 1.2MA in terms of plasma current. Above this threshold, neutron and gamma fluxes become strong function of the plasma current. Neutron and gamma production dynamics is largely influenced by the MHD activity of the RFP plasmas. In particular, a bursty enhancement of neutron yields, correlated with the spontaneous magnetic reconnection processes, occurs almost cyclically in the RFP plasmas. Magnetic reconnection, which is known to be associated to heating and particle acceleration, indeed is also found to modify the energy distribution of the collected neutral atoms having impact on both the Maxwellian component and on the observed higher energy tail. The spontaneous generation of fast particles is of particular interest in RFP plasmas, as it has been proven by means of external beams that high energy ions exhibit good confinement properties, with a classical behavior and no enhanced radial transport. The possible role of such particles in the destabilization of the observed Alfvén eigenmodes is also discussed. Data from RFP experiments are compared to those obtained in low-current tokamak campaigns also performed in RFX-mod.

Published
2016

18. Current sheet fragmentation following magnetic reconnection in RFP plasmas

Author

Cordaro L., Zuin M., Momo B., Martines E., Spolaore M., Cavazzana R., De Masi G., Spagnolo S., Vianello N., Cester D., Stevanato L., Isliker H., and Vlahos L.

Subjects
RFP plasmas, Physics::Plasma Physics, magnetic reconnection, Reversed Field Pinch
Abstract

In a Reversed Field Pinch discharge (RFP), magnetic reconnection events are related to selforganized processes[1]. Along with the action of the continuous dynamo process, discrete quasicyclic relaxation events, leading to rearrangement of magnetic field topology through magnetic reconnection phenomena, have been seen in RFP plasmas, with a dynamics resembling that of sawtooth in tokamak plasmas. In RFX-mod (R = 2m,a = 0.459m), it was shown that a relaxation event is associated with the rapid formation of a localized magnetic perturbation characterized by a main m=0 periodicity [2], resonant on the reversal surface where q = 0. This perturbation corresponds to the formation of a poloidal current sheet. The m=0 activity starts in a localized region around a given toroidal position and then moves with the plasma in a direction opposite to the toroidal current. In this contribution, a characterization of the m=0 perturbations, through the use of a statistical method for the detection of intermittent structures, is presented. Data analysis here reported refers to the toroidal magnetic field perturbations collected by ISIS (Integrated System of Internal Sensors [3]), whose magnetic sensors are placed just below the graphite first-wall (r = 1.03a). A statistical analysis on the magnetic field intermittent structures suggests that current sheets, associated with magnetic reconnection phenomena, are subject to a fragmentation process. This result is in agreement with what predicted by simulations presented in the literature [4], which highlight two important aspects: a current sheet could be naturally subject to fragmentation and a fragmented current sheet represents a more efficient particle accelerator with respect to a monolithic one, because it offers multiple particle acceleration sites [5]. Indeed, we found a relationship between relaxation events in RFP discharges and the neutron fluxes due to DD fusion reactions, suggesting the coupling among relaxation events, particle acceleration and magnetic reconnection phenomena.

Published
2016

19. Overview of the RFX-mod fusion science activity

Author

Zuin, M., primary, Dal Bello, S., additional, Marrelli, L., additional, Puiatti, M.E., additional, Agostinetti, P., additional, Agostini, M., additional, Antoni, V., additional, Auriemma, F., additional, Barbisan, M., additional, Barbui, T., additional, Baruzzo, M., additional, Belli, F., additional, Bettini, P., additional, Bigi, M., additional, Bilel, R., additional, Boldrin, M., additional, Bolzonella, T., additional, Bonfiglio, D., additional, Brombin, M., additional, Buffa, A., additional, Bustreo, C., additional, Canton, A., additional, Cappello, S., additional, Carraro, L., additional, Cavazzana, R., additional, Cester, D., additional, Chacon, L., additional, Chitarin, G., additional, Cooper, W.A., additional, Cordaro, L., additional, Dalla Palma, M., additional, Deambrosis, S., additional, Delogu, R., additional, De Lorenzi, A., additional, De Masi, G., additional, Dong, J.Q., additional, Escande, D.F., additional, Fassina, A., additional, Felici, F., additional, Ferro, A., additional, Finotti, C., additional, Franz, P., additional, Frassinetti, L., additional, Gaio, E., additional, Ghezzi, F., additional, Giudicotti, L., additional, Gnesotto, F., additional, Gobbin, M., additional, Gonzalez, W.A., additional, Grando, L., additional, Guo, S.C., additional, Hanson, J.D., additional, Hirshman, S.P., additional, Innocente, P., additional, Jackson, J.L., additional, Kiyama, S., additional, Komm, M., additional, Kudlacek, O., additional, Laguardia, L., additional, Li, C., additional, Liu, B., additional, Liu, S.F., additional, Liu, Y.Q., additional, López- Bruna, D., additional, Lorenzini, R., additional, Luce, T.C., additional, Luchetta, A., additional, Maistrello, A., additional, Manduchi, G., additional, Mansfield, D.K., additional, Marchiori, G., additional, Marconato, N., additional, Marcuzzi, D., additional, Martin, P., additional, Martines, E., additional, Martini, S., additional, Mazzitelli, G., additional, McCormack, O., additional, Miorin, E., additional, Momo, B., additional, Moresco, M., additional, Narushima, Y., additional, Okabayashi, M., additional, Paccagnella, R., additional, Patel, N., additional, Pavei, M., additional, Peruzzo, S., additional, Pilan, N., additional, Pigatto, L., additional, Piovan, R., additional, Piovesan, P., additional, Piron, C., additional, Piron, L., additional, Predebon, I., additional, Pucella, G., additional, Rea, C., additional, Recchia, M., additional, Rizzolo, A., additional, Rostagni, G., additional, Ruset, C., additional, Sajò-Bohus, L., additional, Sakakita, H., additional, Sanchez, R., additional, Sarff, J.S., additional, Sattin, F., additional, Scarin, P., additional, Schmitz, O., additional, Schneider, W., additional, Siragusa, M., additional, Sonato, P., additional, Spada, E., additional, Spagnolo, S., additional, Spolaore, M., additional, Spong, D.A., additional, Spizzo, G., additional, Stevanato, L., additional, Suzuki, Y., additional, Taliercio, C., additional, Terranova, D., additional, Tudisco, O., additional, Urso, G., additional, Valente, M., additional, Valisa, M., additional, Vallar, M., additional, Veranda, M., additional, Vianello, N., additional, Villone, F., additional, Vincenzi, P., additional, Visonà, N., additional, White, R.B., additional, Xanthopoulos, P., additional, Xu, X.Y., additional, Yanovskiy, V., additional, Zamengo, A., additional, Zanca, P., additional, Zaniol, B., additional, Zanotto, L., additional, Zhang, Y., additional, and Zilli, E., additional

Published
2017
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21. Commissioning and Field Tests of a Van-Mounted System for the Detection of Radioactive Sources and Special Nuclear Material

Author

Cester, D., primary, Lunardon, M., additional, Stevanato, L., additional, Viesti, G., additional, Chandra, R., additional, Davatz, G., additional, Friederich, H., additional, Gendotti, U., additional, Murer, D., additional, Iwanowska-Hanke, J., additional, Sibczynski, P., additional, Moszynski, M., additional, Swiderski, L., additional, Resnati, F., additional, Rubbia, A., additional, Iovene, A., additional, Petrucci, S., additional, Tintori, C., additional, Caccia, M., additional, Chmill, V., additional, Santoro, R., additional, Martemyianov, A., additional, Doherty, M., additional, Carrol, J. L., additional, Christodoulou, G., additional, Stainer, T., additional, and Touramanis, C., additional

Published
2016
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24. Overview of the RFX-mod contribution to the international Fusion Science Program

Author

Puiatti, M.E., primary, Dal Bello, S., additional, Marrelli, L., additional, Martin, P., additional, Agostinetti, P., additional, Agostini, M., additional, Antoni, V., additional, Auriemma, F., additional, Barbisan, M., additional, Barbui, T., additional, Baruzzo, M., additional, Battistella, M., additional, Belli, F., additional, Bettini, P., additional, Bigi, M., additional, Bilel, R., additional, Boldrin, M., additional, Bolzonella, T., additional, Bonfiglio, D., additional, Brombin, M., additional, Buffa, A., additional, Canton, A., additional, Cappello, S., additional, Carraro, L., additional, Cavazzana, R., additional, Cester, D., additional, Chacon, L., additional, Chapman, B.E., additional, Chitarin, G., additional, Ciaccio, G., additional, Cooper, W.A., additional, Dalla Palma, M., additional, Deambrosis, S., additional, Delogu, R., additional, De Lorenzi, A., additional, De Masi, G., additional, Dong, J.Q., additional, Escande, D.F., additional, Esposito, B., additional, Fassina, A., additional, Fellin, F, additional, Ferro, A., additional, Finotti, C., additional, Franz, P., additional, Frassinetti, L., additional, Furno Palumbo, M., additional, Gaio, E., additional, Ghezzi, F., additional, Giudicotti, L., additional, Gnesotto, F., additional, Gobbin, M., additional, Gonzales, W.A., additional, Grando, L., additional, Guo, S.C., additional, Hanson, J.D., additional, Hirshman, S.P., additional, Innocente, P., additional, Jackson, J.L., additional, Kiyama, S., additional, Komm, M., additional, Laguardia, L., additional, Li, C., additional, Liu, S.F., additional, Liu, Y.Q., additional, Lorenzini, R., additional, Luce, T.C., additional, Luchetta, A., additional, Maistrello, A., additional, Manduchi, G., additional, Mansfield, D.K., additional, Marchiori, G., additional, Marconato, N., additional, Marocco, D., additional, Marcuzzi, D., additional, Martines, E., additional, Martini, S., additional, Matsunaga, G., additional, Mazzitelli, G., additional, Miorin, E., additional, Momo, B., additional, Moresco, M., additional, Okabayashi, M., additional, Olofsson, E., additional, Paccagnella, R., additional, Patel, N., additional, Pavei, M., additional, Peruzzo, S., additional, Pilan, N., additional, Pigatto, L., additional, Piovan, R., additional, Piovesan, P., additional, Piron, C., additional, Piron, L., additional, Predebon, I., additional, Rea, C., additional, Recchia, M., additional, Rigato, V., additional, Rizzolo, A., additional, Roquemore, A.L., additional, Rostagni, G., additional, Ruset, C, additional, Ruzzon, A., additional, Sajò-Bohus, L., additional, Sakakita, H., additional, Sanchez, R., additional, Sarff, J.S., additional, Sartori, E., additional, Sattin, F., additional, Scaggion, A., additional, Scarin, P., additional, Schmitz, O., additional, Sonato, P., additional, Spada, E., additional, Spagnolo, S., additional, Spolaore, M., additional, Spong, D.A., additional, Spizzo, G., additional, Stevanato, L., additional, Takechi, M., additional, Taliercio, C., additional, Terranova, D., additional, Trevisan, G.L., additional, Urso, G., additional, Valente, M., additional, Valisa, M., additional, Veranda, M., additional, Vianello, N., additional, Viesti, G., additional, Villone, F., additional, Vincenzi, P., additional, Visona', N., additional, Wang, Z.R., additional, White, R.B., additional, Xanthopoulos, P., additional, Xu, X.Y., additional, Yanovskiy, V., additional, Zamengo, A., additional, Zanca, P., additional, Zaniol, B., additional, Zanotto, L., additional, Zilli, E., additional, and Zuin, M., additional

Published
2015
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35. An integrated mobile system for port security

Author

Cester, D., primary, Fabris, D., additional, Lunardon, M., additional, Moretto, S., additional, Nebbia, G., additional, Pesente, S., additional, Stevanato, L., additional, Viesti, G., additional, Neri, F., additional, Petrucci, S., additional, Selmi, S., additional, and Tintori, C., additional

Published
2011
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36. Neutron detection in a high gamma ray background with liquid scintillators.

Author

Stevanato, L., Cester, D., Nebbia, G., and Viesti, G.

Subjects
*NEUTRON counters, *GAMMA rays, *LIQUID scintillators, *RADIATION doses, *PROBABILITY theory, *PERFORMANCE evaluation
Abstract

The capability of liquid scintillator (namely 2" × 2" cells of EJ301 and EJ309) of detecting neutrons in a very high gamma ray background is explored. A weak 252Cf source has been detected in a high 137Cs gamma ray background corresponding to a dose rate of 100 μSv/h with probability of detection in compliance with IEC requirements for hand held instruments. Tests were performed with new generation of CAEN digitizers, in particular the V1720 (8 Channel 12bit 250 MS/s) one. [ABSTRACT FROM AUTHOR]

Published
2013
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37. Digital front-end electronics for a tagged neutron inspection system.

Author

Cester, D., Nebbia, G., Stevanato, L., and Viesti, G.

Subjects
*ELECTRONICS, *NEUTRONS, *NUCLEAR counters, *PARTICLES (Nuclear physics), *CALIFORNIUM
Abstract

In this paper, we shall present a simple VME front-end system that employs the FADC CAEN V1720 8- channel 12-bit 250-MS/s digitizer. This system produces coincidence spectra between the trigger particle and other detectors and it replaces the traditional technique of chaining analog electronics. Tests have been performed using a pulser working at different frequencies as well as employing a 252Cf source in concert with an array of detectors. [ABSTRACT FROM AUTHOR]

Published
2013
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38. An integrated mobile system for non-destructive analysis with tagged neutrons.

Author

Cester, D., Nebbia, G., Stevanato, L., Viesti, G., Neri, F., Petrucci, S., Selmi, S., and Tintori, C.

Subjects
*NEUTRONS, *GAMMA rays, *SYSTEMS design, *RADIOACTIVE substances, *HARBOR security, *INTEGRATED circuits, *ELECTROMAGNETIC waves
Abstract

An integrated mobile system for port security is presented. The system is designed to perform active investigations by using the tagged neutron inspection technique of suspect dangerous materials as well as passive measurements of neutrons and gamma rays to search and identify radioactive and special nuclear materials. The system has been employed in detection tests of special nuclear material as well as in a seaport demonstration. [ABSTRACT FROM AUTHOR]

Published
2013
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39. Special nuclear material detection studies with the SMANDRA mobile system.

Author

Cester, D., Nebbia, G., Stevanato, L., Viesti, G., Neri, F., Petrucci, S., Selmi, S., Tintori, C., Peerani, P., and Tomanin, A.

Subjects
*DETECTION of radioactive substances, *MOBILE communication systems, *SENSITIVITY analysis, *NEUTRONS, *PLUTONIUM, *URANIUM, *GAMMA ray spectrometry
Abstract

The detection of special nuclear material has been studied with the SMANDRA mobile inspection system used both as a high sensitivity passive neutron/gamma spectroscopic tool and as an active inspection device using tagged neutrons. The detection of plutonium samples is possible with passive interrogation, the passive detection of uranium being much more difficult because of the low neutron yield and of the easiness of shielding the gamma rays. However, we show that active interrogation with tagged neutrons is able to provide signatures for the discrimination of uranium against other materials. [ABSTRACT FROM AUTHOR]

Published
2012
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40. High rate read-out of LaBr(Ce) scintillator with the CAEN V1720 FADC.

Author

Cester, D., Nebbia, G., Stevanato, L., Viesti, G., Neri, F., Petrucci, S., Selmi, S., and Tintori, C.

Subjects
*SCINTILLATORS, *LANTHANUM compounds, *NUCLEAR counters, *SIGNAL processing, *OPTICAL resolution, *ELECTRONICS, *NEUTRON beams, *STANDARDS
Abstract

The energy resolution of a LaBr(Ce) detector has been studied as a function of the count rate up to 340 kHz by using a 12bit 250 MS/s V1720 digitizer. The time resolution achieved by processing off line the digitized signals has been also determined. When results are compared with the ones obtained by using standard NIM electronics, it appears that the energy resolution obtained with the V1720 digitizer is better than the one with the NIM standard whereas the time resolution is poorer. However the time resolution by using the V1720 digitizer of about 1.2 ns [FWHM] seems to be sufficient for applications in Non-Destructive Analysis of large objects with tagged neutron beams. [ABSTRACT FROM AUTHOR]

Published
2012
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41. Runaway electron mitigation by applied magnetic perturbations in RFX-mod tokamak plasmas

Author

Maria Ester Puiatti, Luca Stevanato, D. Cester, M. Gobbin, Roscoe White, Massimo Nocente, Matteo Zuin, Lionello Marrelli, M. Valisa, P. Piovesan, Gobbin, M, Valisa, M, White, R, Cester, D, Marrelli, L, Nocente, M, Piovesan, P, Stevanato, L, Puiatti, M, and Zuin, M

Subjects
Nuclear and High Energy Physics, Guiding center, Tokamak, MHD, Perturbation (astronomy), Electron, 01 natural sciences, runaway electron, 010305 fluids & plasmas, law.invention, Physics::Plasma Physics, law, 0103 physical sciences, magnetic perturbations, Magnetohydrodynamic drive, 010306 general physics, tokamak, Nuclear and High Energy Physic, Physics, magnetic perturbation, runaway electrons, Plasma, Condensed Matter Physics, disruption, Computational physics, Amplitude, Atomic physics, Magnetohydrodynamics
Abstract

Thanks to its advanced system for the control of magnetohydrodynamic modes, the RFX-mod device run as a tokamak is particularly suited to the study of the possible impact on runaway electron (RE) de-confinement in response to applied magnetic perturbations. This paper shows that during the flat-top phase in RFX-mod discharges, with a plasma current of I p ∼ 150 kA and a low density ( n e < 10 19 m−3), the amount of REs scales with the m = 2,n = 1 perturbation both in q(a) q(a) > 2 plasmas. Similar results have also been obtained in post-disruption phases, but still with limited statistics. The mechanisms generating REs and the effect of magnetic perturbation (MP) on their confinement are interpreted by numerical simulations with the relativistic guiding center code ORBIT. The role played by different magnetic equilibria on the energy of REs and on their loss rates is investigated. ORBIT simulations indicate that RE-enhanced losses are associated with a raised level of stochasticity, the effect being more pronounced when the MP amplitude is higher and internally resonant.

Published
2017
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42. 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
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43. Overview of the RFX-mod contribution to the international Fusion Science Program

Author

M. Pavei, Alessandra Canton, Matteo Agostini, R. Piovan, Matteo Zuin, G. Mazzitelli, L. Piron, N. Vianello, J.Q. Dong, B. E. Chapman, A. Zamengo, Gianluca Spizzo, Paolo Zanca, T. Barbui, Hajime Sakakita, Piergiorgio Sonato, Nicola Pilan, Yueqiang Liu, Daniele Bonfiglio, P. Piovesan, Lorella Carraro, T.C. Luce, J. L. Jackson, C. Finotti, E. Miorin, M. Recchia, S.P. Hirshman, Rita Lorenzini, Andrea Rizzolo, Roberto Paccagnella, G. Ciaccio, A. Scaggion, Enrico Zilli, Nicolò Marconato, Paolo Scarin, S. Martini, M. Baruzzo, James D. Hanson, M. Veranda, L. Marrelli, M. Bigi, Marco Barbisan, W. A. Cooper, L. Zanotto, Piero Agostinetti, L. Laguardia, Chenguang Li, C. Taliercio, F. Fellin, Oliver Schmitz, Cristian Ruset, Luca Grando, Zhirui Wang, Lorenzo Frassinetti, Silvia Spagnolo, X. Y. Xu, Simone Peruzzo, B. Esposito, Erik Olofsson, Elena Gaio, M. Furno Palumbo, M. Okabayashi, Nisarg Patel, G. L. Trevisan, Matthias Komm, M. Spolaore, Francesco Gnesotto, S. C. Guo, Raul Sanchez, D. Terranova, Susanna Cappello, R. Bilel, G. Urso, Marco Gobbin, Fabio Villone, E. Spada, M. Moresco, D. Cester, Emanuele Sartori, L. Pigatto, Leonardo Giudicotti, B. Momo, Tommaso Bolzonella, Piero Martin, Luis Chacon, A. L. Roquemore, F. Belli, Barbara Zaniol, C. Piron, F. Sattin, N. Visona, F. Ghezzi, R. Delogu, Emilio Martines, Diego Marcuzzi, D. F. Escande, A. De Lorenzi, M. Dalla Palma, Paolo Franz, Cristina Rea, Adriano Luchetta, Paolo Bettini, Roscoe White, A. Maistrello, Alessandro Fassina, G. Rostagni, Manabu Takechi, Roberto Cavazzana, G. Viesti, M. Boldrin, V. Yanovskiy, Giuseppe Marchiori, D.K. Mansfield, Satoru Kiyama, W. A. Gonzales, M. Valisa, A. Buffa, Pavlos Xanthopoulos, J. S. Sarff, M. E. Puiatti, Go Matsunaga, M. Valente, S. M. Deambrosis, Alberto Ferro, Paolo Innocente, Italo Predebon, V. Rigato, S. Dal Bello, Gabriele Manduchi, Fulvio Auriemma, G. De Masi, P. Vincenzi, Donald A. Spong, M. Battistella, Songfen Liu, D. Marocco, M. Brombin, Laszlo Sajo-Bohus, Giuseppe Chitarin, A. Ruzzon, V. Antoni, L. Stevanato, Consorzio RFX, Associazione Euratom/ENEA sulla Fusione (RFX), Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Laboratori Nazionali di Frascati (LNF), Istituto Nazionale di Fisica Nucleare (INFN), National Institute for Laser, Plasma and Radiation Physics (INFLPR), STMicroelectronics [Crolles] (ST-CROLLES), Canadian Institute for Theoretical Astrophysics (CITA), Département Méthodes et Modèles Mathématiques pour l'Industrie (3MI-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Centre G2I, Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Stockholm], Stockholm University, Inst Subtrop Agr, Res Ctr Healthy Breeding Livestock & Poultry, Hunan Engn, Chinese Academy of Sciences [Changchun Branch] (CAS), Inst Subtrop Agr, Res Ctr Anim & Poultry Sci, Inst Subtrop Agr, Key Lab Agroecol Proc Subtrop Reg, Puiatti, M, Dal Bello, S, Marrelli, L, Martin, P, Agostinetti, P, Agostini, M, Antoni, V, Auriemma, F, Barbisan, M, Barbui, T, Baruzzo, M, Battistella, M, Belli, F, Bettini, P, Bigi, M, Bilel, R, Boldrin, M, Bolzonella, T, Bonfiglio, D, Brombin, M, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cester, D, Chacon, L, Chapman, B, Chitarin, G, Ciaccio, G, Cooper, W, Dalla Palma, M, Deambrosis, S, Delogu, R, De Lorenzi, A, De Masi, G, Dong, J, Escande, D, Esposito, B, Fassina, A, Fellin, F, Ferro, A, Finotti, C, Franz, P, Frassinetti, L, Palumbo, M, Gaio, E, Ghezzi, F, Giudicotti, L, Gnesotto, F, Gobbin, M, Gonzales, W, Grando, L, Guo, S, Hanson, J, Hirshman, S, Innocente, P, Jackson, J, Kiyama, S, Komm, M, Laguardia, L, Li, C, Liu, S, Liu, Y, Lorenzini, R, Luce, T, Luchetta, A, Maistrello, A, Manduchi, G, Mansfield, D, Marchiori, G, Marconato, N, Marocco, D, Marcuzzi, D, Martines, E, Martini, S, Matsunaga, G, Mazzitelli, G, Miorin, E, Momo, B, Moresco, M, Okabayashi, M, Olofsson, E, Paccagnella, R, Patel, N, Pavei, M, Peruzzo, S, Pilan, N, Pigatto, L, Piovan, R, Piovesan, P, Piron, C, Piron, L, Predebon, I, Rea, C, Recchia, M, Rigato, V, Rizzolo, A, Roquemore, A, Rostagni, G, Ruset, C, Ruzzon, A, Sajo-Bohus, L, Sakakita, H, Sanchez, R, Sarff, J, Sartori, E, Sattin, F, Scaggion, A, Scarin, P, Schmitz, O, Sonato, P, Spada, E, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Stevanato, L, Takechi, M, Taliercio, C, Terranova, D, Trevisan, G, Urso, G, Valente, M, Valisa, M, Veranda, M, Vianello, N, Viesti, G, Villone, F, Vincenzi, P, Visona', N, Wang, Z, White, R, Xanthopoulos, P, Xu, X, Yanovskiy, V, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zuin, M, and Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA)

Subjects
Convection, Physics, [PHYS]Physics [physics], Nuclear and High Energy Physics, Toroid, Tokamak, Reversed field pinch, Turbulence, single helicity, Electron, Mechanics, Sawtooth wave, reversed field pinch, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, law.invention, 3D boundary, law, Physics::Plasma Physics, 0103 physical sciences, Magnetohydrodynamics, Atomic physics, 010306 general physics, tokamak
Abstract

25th Fusion Energy Conference (FEC), Govt Russian Federat, St ă Petersburg, RUSSIA, OCT 13-18, 2014; International audience; The RFX-mod device is operated both as a reversed field pinch (RFP), ă where advanced regimes featuring helical shape develop, and as a ă tokamak. Due to its flexibility, RFX-mod is contributing to the solution ă of key issues in the roadmap to ITER and DEMO, including MHD instability ă control, internal transport barriers, edge transport and turbulence, ă isotopic effect, high density limit and three-dimensional (3D) ă non-linear MHD modelling. This paper reports recent advancements in the ă understanding of the self-organized helical states, featuring a strong ă electron transport barrier, in the RFP configuration; the physical ă mechanism driving the residual transport at the barrier has been ă investigated. Following the first experiments with deuterium as the ă filling gas, new results concerning the isotope effect in the RFP are ă discussed. Studies on the high density limit show that in the RFP it is ă related to a toroidal particle accumulation due to the onset of a ă convective cell. In the tokamak configuration, q(a) regimes down to q(a) ă = 1.2 have been pioneered, with (2,1) tearing mode (TM) mitigated and ă (2,1) resistive wall mode (RWM) stabilized: the control of such modes ă can be obtained both by poloidal and radial sensors. Progress has been ă made in the avoidance of disruptions due to the (2,1) TM by applying ă q(a) control, and on the general issue of error field control. The ă effect of externally applied 3D fields on plasma flow and edge ă turbulence, sawtooth control and runaway electron decorrelation has been ă analysed. The experimental program is supported by substantial ă theoretical activity: 3D non-linear visco-resistive MHD and non-local ă transport modelling have been advanced; RWMs have been studied by a ă toroidal MHD kinetic hybrid stability code.

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44. 3D-navigation for SI screw fixation - How does it affect radiation exposure for patients and medical personnel?

Author

Kalbas Y, Hoch Y, Klingebiel FK, Klee O, Cester D, Halvachizadeh S, Berk T, Wanner GA, Pfeifer R, Pape HC, and Hasler RM

Subjects
Humans, Fracture Fixation, Internal methods, Cohort Studies, Retrospective Studies, Bone Screws, Fluoroscopy methods, Fractures, Bone surgery, Surgery, Computer-Assisted methods, Radiation Exposure prevention & control, Pelvic Bones injuries
Abstract

Background: 3D-navigation for percutaneous sacroiliac (SI) screw fixation is becoming increasingly common and several studies report great advantages of this technology. However, there is still limited clinical evidence on the efficacy regarding radiation exposure for patient and personnel., Methods: This is a retrospective, single-center cohort study. All patients who underwent percutaneous sacroiliac screw fixation for an injury of the posterior pelvic ring from 2014 to 2021 were screened. Inclusion criteria were: conclusive radiation dosage reports, signed informed consent, a twelve month follow up and a complete data set. Patients were stratified in two groups (3D-navigation (Group 3D-N) vs. control (Group F)) based on the imaging modality used. Primary outcomes were radiation exposure for patient and personnel. Secondary outcomes were reoperations, complications, and intraoperative precision., Results: Of 392 patients screened, 174 patients (3D-N: n = 50, F: n = 124) could be included for final analysis. We noted a significant reduction of the dose corresponding to potential radiation exposure for medical personnel (-15.3 mGy, 95 %CI: -2.1 to -28.5, p = 0.0232), but also a significant increase of the dose quantifying radiation exposure for patients (+77.0 mGy, 95 %CI: +53.3 to +100.6, p < 0.0001), when using navigation. In addition, the rate of radiographic malplacement was significantly reduced (F: 11.3% vs. 3D-N: 0 %, p = 0.0113) despite a substantial increase in transsacral screw placement (F: 19.4% vs. 3D-N: 76 %)., Conclusion: Our data clearly suggests that the use of 3D-navigation for percutaneous SI screw fixation decreases radiation exposure for medical personnel, while increasing radiation exposure for patients. Furthermore, intraoperative precision is improved, even in more challenging operations., Competing Interests: Declaration of Competing Interest All authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Published
2024
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45. Fully automated breast segmentation on spiral breast computed tomography images.

Author

Shim S, Cester D, Ruby L, Bluethgen C, Marcon M, Berger N, Unkelbach J, and Boss A

Subjects
Humans, Female, Tomography, X-Ray Computed methods, Breast Density, Algorithms, Breast diagnostic imaging, Breast Neoplasms diagnostic imaging
Abstract

Introduction: The quantification of the amount of the glandular tissue and breast density is important to assess breast cancer risk. Novel photon-counting breast computed tomography (CT) technology has the potential to quantify them. For accurate analysis, a dedicated method to segment the breast components-the adipose and glandular tissue, skin, pectoralis muscle, skinfold section, rib, and implant-is required. We propose a fully automated breast segmentation method for breast CT images., Methods: The framework consists of four parts: (1) investigate, (2) segment the components excluding adipose and glandular tissue, (3) assess the breast density, and (4) iteratively segment the glandular tissue according to the estimated density. For the method, adapted seeded watershed and region growing algorithm were dedicatedly developed for the breast CT images and optimized on 68 breast images. The segmentation performance was qualitatively (five-point Likert scale) and quantitatively (Dice similarity coefficient [DSC] and difference coefficient [DC]) demonstrated according to human reading by experienced radiologists., Results: The performance evaluation on each component and overall segmentation for 17 breast CT images resulted in DSCs ranging 0.90-0.97 and in DCs 0.01-0.08. The readers rated 4.5-4.8 (5 highest score) with an excellent inter-reader agreement. The breast density varied by 3.7%-7.1% when including mis-segmented muscle or skin., Conclusion: The automatic segmentation results coincided with the human expert's reading. The accurate segmentation is important to avoid the significant bias in breast density analysis. Our method enables accurate quantification of the breast density and amount of the glandular tissue that is directly related to breast cancer risk., (© 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine.)

Published
2022
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46. Efficiency evaluation of leaded glasses and visors for eye lens dose reduction during fluoroscopy guided interventional procedures.

Author

Samara ET, Cester D, Furlan M, Pfammatter T, Frauenfelder T, and Stüssi A

Subjects
Drug Tapering, Fluoroscopy, Humans, Radiation Dosage, Radiology, Interventional, Lens, Crystalline, Occupational Exposure prevention & control, Radiation Exposure prevention & control, Radiation Protection methods
Abstract

Purpose: Fluoroscopy guided interventional procedures guarantee high benefits for patients, but are associated with high levels of radiation exposure for the medical staff. Their increasing use and complexity results in even higher radiation exposures, with a risk to exceed the annual dose limit of 20 mSv for the eye lens. The aim of the study was to evaluate the potential dose reduction of eye lens exposure for lead glasses and for two types of visors (half and full), used by physicians performing interventional procedures., Methods: Eye lens dose measurements were carried out on an anthropomorphic phantom simulating a physician performing a fluoroscopy guided interventional procedure. Dose reduction factors were calculated using high sensitivity thermoluminescent dosimeters. Moreover, a spatial dose distribution was generated for the two visors., Results: The dose reduction coefficient was found to be 1.6 for the glasses, 1.2 for the half visor and 4.5 for the full visor., Conclusions: Optimal radiation protection requires a combination of different radiation protection equipment. Full visors that cover all the face of the operator are recommended, as they absorb scattered radiation reaching the eyes from all directions. Full visors should be prioritized over radiation protection glasses for cases where other protective equipment such as ceiling shielding cannot be used., (Copyright © 2022. Published by Elsevier Ltd.)

Published
2022
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47. Virtual monoenergetic images from dual-energy CT: systematic assessment of task-based image quality performance.

Author

Cester D, Eberhard M, Alkadhi H, and Euler A

Abstract

Background: To compare task-based image quality (TB-IQ) among virtual monoenergetic images (VMI) and linear-blended images (LBI) from dual-energy CT as a function of contrast task, radiation dose, size, and lesion diameter., Methods: A TB-IQ phantom (Mercury Phantom 4.0, Sun Nuclear Corporation) was imaged on a third-generation dual-source dual-energy CT with 100/Sn150 kVp at three volume CT dose levels (5, 10, 15 mGy). Three size sections (diameters 16, 26, 36 cm) with subsections for image noise and spatial resolution analysis were used. High-contrast tasks (e.g., calcium-containing stone and vascular lesion) were emulated using bone and iodine inserts. A low-contrast task (e.g., low-contrast lesion or hematoma) was emulated using a polystyrene insert. VMI at 40-190 keV and LBI were reconstructed. Noise power spectrum (NPS) determined the noise magnitude and texture. Spatial resolution was assessed using the task-transfer function (TTF) of the three inserts. The detectability index (d') served as TB-IQ metric., Results: Noise magnitude increased with increasing phantom size, decreasing dose, and decreasing VMI-energy. Overall, noise magnitude was higher for VMI at 40-60 keV compared to LBI (range of noise increase, 3-124%). Blotchier noise texture was found for low and high VMIs (40-60 keV, 130-190 keV) compared to LBI. No difference in spatial resolution was observed for high contrast tasks. d' increased with increasing dose level or lesion diameter and decreasing size. For high-contrast tasks, d' was higher at 40-80 keV and lower at high VMIs. For the low-contrast task, d' was higher for VMI at 70-90 keV and lower at 40-60 keV., Conclusions: Task-based image quality differed among VMI-energy and LBI dependent on the contrast task, dose level, phantom size, and lesion diameter. Image quality could be optimized by tailoring VMI-energy to the contrast task. Considering the clinical relevance of iodine, VMIs at 50-60 keV could be proposed as an alternative to LBI., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/qims-21-477). The authors have no conflicts of interest to declare., (2022 Quantitative Imaging in Medicine and Surgery. All rights reserved.)

Published
2022
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48. Sources of Variability in Shear Wave Speed and Dispersion Quantification with Ultrasound Elastography: A Phantom Study.

Author

Korta Martiartu N, Nambiar S, Nascimento Kirchner I, Paverd C, Cester D, Frauenfelder T, Ruby L, and Rominger MB

Subjects
Elasticity, Liver diagnostic imaging, Phantoms, Imaging, Ultrasonography, Elasticity Imaging Techniques
Abstract

There is a growing interest in quantifying shear-wave dispersion (SWD) with ultrasound shear-wave elastography (SWE). Recent studies suggest that SWD complements shear-wave speed (SWS) in diffuse liver disease diagnosis. To accurately interpret these metrics in clinical practice, we analyzed the impact of operator-dependent acquisition parameters on SWD and SWS measurements. Considered parameters were the acquisition depth, lateral position and size of the region of interest (ROI), as well as the size of the SWE acquisition box. Measurements were performed using the Canon Aplio i800 system (Canon Medical Systems, Otawara, Tochigi, Japan) and four homogeneous elasticity phantoms with certified stiffness values ranging from 3.7 to 44 kPa. In general, SWD exhibited two to three times greater variability than SWS. The acquisition depth was the main variance-contributing factor for both SWS and SWD, which decayed significantly with depth. The lateral ROI position contributed as much as the acquisition depth to the total variance in SWD. Locations close to the initial shear-wave excitation pulse were more robust to biases because of inaccurate probe-phantom coupling. The size of the ROI and acquisition box did not introduce significant variations. These results suggest that future guidelines on multiparametric elastography should account for the depth- and lateral-dependent variability of measurements., Competing Interests: Conflict of interest disclosure This work received financial support from Canon Medical., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Published
2021
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49. Virtual Monoenergetic Images of Dual-Energy CT-Impact on Repeatability, Reproducibility, and Classification in Radiomics.

Author

Euler A, Laqua FC, Cester D, Lohaus N, Sartoretti T, Pinto Dos Santos D, Alkadhi H, and Baessler B

Abstract

The purpose of this study was to (i) evaluate the test-retest repeatability and reproducibility of radiomic features in virtual monoenergetic images (VMI) from dual-energy CT (DECT) depending on VMI energy (40, 50, 75, 120, 190 keV), radiation dose (5 and 15 mGy), and DECT approach (dual-source and split-filter DECT) in a phantom (ex vivo), and (ii) to assess the impact of VMI energy and feature repeatability on machine-learning-based classification in vivo in 72 patients with 72 hypodense liver lesions. Feature repeatability and reproducibility were determined by concordance-correlation-coefficient (CCC) and dynamic range (DR) ≥0.9. Test-retest repeatability was high within the same VMI energies and scan conditions (percentage of repeatable features ranging from 74% for SFDE mode at 40 keV and 15 mGy to 86% for DSDE at 190 keV and 15 mGy), while reproducibility varied substantially across different VMI energies and DECTs (percentage of reproducible features ranging from 32.8% for SFDE at 5 mGy comparing 40 with 190 keV to 99.2% for DSDE at 15 mGy comparing 40 with 50 keV). No major differences were observed between the two radiation doses (<10%) in all pair-wise comparisons. In vivo, machine learning classification using penalized regression and random forests resulted in the best discrimination of hemangiomas and metastases at low-energy VMI (40 keV), and for cysts at high-energy VMI (120 keV). Feature selection based on feature repeatability did not improve classification performance. Our results demonstrate the high repeatability of radiomics features when keeping scan and reconstruction conditions constant. Reproducibility diminished when using different VMI energies or DECT approaches. The choice of optimal VMI energy improved lesion classification in vivo and should hence be adapted to the specific task.

Published
2021
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50. Radiomics in medical imaging-"how-to" guide and critical reflection.

Author

van Timmeren JE, Cester D, Tanadini-Lang S, Alkadhi H, and Baessler B

Abstract

Radiomics is a quantitative approach to medical imaging, which aims at enhancing the existing data available to clinicians by means of advanced mathematical analysis. Through mathematical extraction of the spatial distribution of signal intensities and pixel interrelationships, radiomics quantifies textural information by using analysis methods from the field of artificial intelligence. Various studies from different fields in imaging have been published so far, highlighting the potential of radiomics to enhance clinical decision-making. However, the field faces several important challenges, which are mainly caused by the various technical factors influencing the extracted radiomic features.The aim of the present review is twofold: first, we present the typical workflow of a radiomics analysis and deliver a practical "how-to" guide for a typical radiomics analysis. Second, we discuss the current limitations of radiomics, suggest potential improvements, and summarize relevant literature on the subject.

Published
2020
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