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1. Development of a new dynamic test procedure for the laboratory characterization of a whole heating and cooling system

Author

Roberto Fedrizzi, Anton Soppelsa, and Diego Menegon

Subjects
Engineering, Emulation, business.industry, 020209 energy, Mechanical Engineering, 02 engineering and technology, Building and Construction, Test method, Management, Monitoring, Policy and Law, 021001 nanoscience & nanotechnology, law.invention, Test (assessment), General Energy, Test case, law, 0202 electrical engineering, electronic engineering, information engineering, Water cooling, 0210 nano-technology, business, Cluster analysis, Simulation, Heat pump, Dynamic testing
Abstract

The performance of heating and cooling systems are affected by their dynamic operating conditions. As a consequence, a sound evaluation of system performance should be done through a dynamic test procedure. However, the complexity, the cost, and the time for such type of experimentation are obstacles to the diffusion of this test method. A new whole system test procedure was developed to reduce its potential failure. The test method considers the emulation of system components that cannot be installed in the laboratory, while the selection of short-yet-significant test sequence is performed classifying the days of the year with clustering analysis. The procedure was applied to a solar-assisted heat pump system in four different European climates. The seasonal performance figures are extrapolated from the test results and compared with the numerical simulations of the entire heating and cooling system. In all test cases the seasonal performance factors are lower than the simulated ones by approximately 10%. The results obtained with dynamic tests confirm the necessity of their implementation, since they provide useful information to improve the system layout and control. In this way, the manufacturers can introduce more efficient products into the market.

Published
2017
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3. An integral approach to plasma shape control

Author

D. Ciscato, Anton Soppelsa, Alessandro Beghi, M. Cavinato, Angelo Cenedese, and S. Simionato

Subjects
Physics, Tokamak, Plasma surface, Mechanical Engineering, B-spline, Mathematical analysis, Plasma, Fusion power, law.invention, Shape control, Spline (mathematics), Nuclear Energy and Engineering, Physics::Plasma Physics, law, General Materials Science, Civil and Structural Engineering
Abstract

A novel representation of the plasma boundary is presented, which employs a B-spline approach to describe the deformation of the plasma surface in an integral way, without resorting to the local properties of the shape as in the gap technique. The evolution of such a curve on the poloidal plane corresponds to that of the plasma shape and a spline controller is designed to counteract disturbances and regulate the plasma shape error during the discharge. The comparison with a gap controller highlights the accuracy in the control capability of the spline controller and its completeness, in the sense that the control of the spline curve implies (but is not implied by) the control of the gaps.

Published
2005
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4. RFX-mod: A multi-configuration fusion facility for three-dimensional physics studies

Author

Alessandra Canton, Matteo Zuin, D. F. Escande, Roberto Paccagnella, Federica Bonomo, E. Martines, Anton Soppelsa, L. Zanotto, Rita Lorenzini, Alessandro Fassina, M. Baruzzo, Paolo Scarin, Daniele Bonfiglio, Roberto Cavazzana, Barbara Zaniol, M. Veranda, D. Terranova, G. De Masi, Piero Martin, L. Piron, M. E. Puiatti, P. Piovesan, Luis Chacon, N. Vianello, G. Ciaccio, L. Marrelli, Lorella Carraro, Susanna Cappello, Gianluca Spizzo, Marco Gobbin, Paolo Zanca, Paolo Franz, M. Valisa, M. Spolaore, Paolo Innocente, Fulvio Auriemma, Matteo Agostini, B. Momo, Tommaso Bolzonella, Piovesan, P, Bonfiglio, D, Auriemma, F, Bonomo, F, Carraro, L, Cavazzana, R, De Masi, G, Fassina, A, Franz, P, Gobbin, M, Marrelli, L, Martin, P, Martines, E, Momo, B, Piron, L, Valisa, M, Veranda, M, Vianello, N, Zaniol, B, Agostini, M, Baruzzo, M, Bolzonella, T, Canton, A, Cappello, S, Chacon, L, Ciaccio, G, Escande, D, Innocente, P, Lorenzini, R, Paccagnella, R, Puiatti, M, Scarin, P, Soppelsa, A, Spizzo, G, Spolaore, M, Terranova, D, Zanca, P, Zanotto, L, and Zuin, M

Subjects
Physics, RFX-mod, Tokamak, Reversed field pinch, PLASMAS, reversed field pinch, Plasma, Condensed Matter Physics, Helicity, PERTURBATIONS, law.invention, Computational physics, Nonlinear system, law, RFP, Pinch, Magnetohydrodynamic drive, Atomic physics, FIELD, Stellarator
Abstract

RFX-mod [Sonato et al., Fusion Eng. Des. 66, 161 (2003)] exploits its 192 active coils in both reversed-field pinch (RFP) and tokamak configurations with varying degrees of 3D shaping, providing also a test bed for validating stellarator codes and 3D nonlinear magnetohydrodynamic codes. This makes RFX-mod a unique and flexible facility for comparative studies on 3D shaping and control. The paper discusses how 3D fields allow access to RFP and tokamak advanced regimes. 3D fields are used to feedback control Single Helicity (SH) RFP equilibria with 1/7 helicity up to similar to 2 MA. They also allow accessing SH regimes with higher density (Greenwald fraction up to 0.5), presently inaccessible in spontaneous SH regimes. Feedback on the 2/1 resistive-wall mode in RFX-mod tokamak plasmas allows for safe operation at q(a) < 2, an almost unexplored promising regime. Forcing the 2/1 mode to saturate at finite but small level, a helical tokamak equilibrium with significant n=1 modulation is produced and a new way to tailor sawteeth is found. The effects of different levels of 3D shaping on momentum transport in both RFP and tokamak helical states are discussed.

Published
2013
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5. Dynamic simulator of RWM control for fusion devices: modelling and experimental validation on RFX-mod

Author

Tommaso Bolzonella, M. Baruzzo, Giuseppe Marchiori, Anton Soppelsa, Yueqiang Liu, and Fabio Villone

Subjects
Nuclear and High Energy Physics, State variable, Tokamak, REVERSED-FIELD PINCHES, Computer science, INTELLIGENT SHELL, ACTIVE FEEDBACK STABILIZATION, Condensed Matter Physics, Flight simulator, law.invention, RESISTIVE WALL MODES, EXTERNAL-MODES, Control theory, law, Physics::Plasma Physics, Control system, Benchmark (computing), Time domain, Plasma stability, Simulation
Abstract

A new integrated simulator for experiments of resistive wall mode (RWM) closed-loop control and its benchmark against experimental data are presented. The numerical tool couples in a self-consistent way a full 3D finite element description of the machine boundaries (Cariddi code), a 2D toroidal model of RFP plasma stability (MARS-F code) and a realistic representation of the RFX-mod control system producing an overall dynamic model cast in the state variable space. In this way a full dynamic ‘flight simulator’ of RWM control experiments has been implemented where the interaction of proportional–integral–derivative controller gains and plasma equilibrium parameters can be explored. As an application of the new integrated tool, closed-loop RWM stability analyses have been benchmarked against experimental data. In this way it was possible to experimentally prove that the control simulator correctly reproduces closed-loop RWM growth rates under different control conditions. Time domain simulations were also run to assess the overall accuracy of the model including the presence of non-linear blocks. The achieved results are discussed in connection with the broader international effort towards an effective control of RWMs in both tokamak and RFP configurations.

Published
2012
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6. RWM control studies on RFX-mod with a limited set of active coils

Author

M. Baruzzo, Fabio Villone, Manabu Takechi, Tommaso Bolzonella, Giuseppe Marchiori, Gabriele Manduchi, Yueqiang Liu, and Anton Soppelsa

Subjects
Physics, Nuclear and High Energy Physics, State variable, Tokamak, Toroid, Reversed field pinch, TOKAMAKS, INTELLIGENT SHELL, FEEDBACK STABILIZATION, Condensed Matter Physics, Finite element method, law.invention, RESISTIVE WALL MODES, Physics::Plasma Physics, Electromagnetic coil, law, Control theory, Control system, Plasma stability
Abstract

In this paper, the results of resistive wall mode (RWM) control experiments using several sets of active coils are presented. The control effectiveness as a function of coil number and covered torus surface is studied in the RFX-mod device, thanks to the powerful and flexible MHD active control system. Active control is tried using similar coil number and size both in the reversed field pinch (RFP) and in the tokamak configurations, giving a good experimental set to exploit the differences between the two cases. The experimental results are compared with predictions by a new integrated simulator for closed loop RWM growth. The numerical tool couples, in a self-consistent way, a full 3D finite element description of the machine boundaries, a 2D toroidal model of RFP plasma stability and a model of the RFX-mod control system, producing an overall dynamic model cast in the state variable space. In this way a full dynamic flight simulator of RWM control experiments is implemented, where coil coverage and experimental proportional–integral–derivative gains are explored in simulations. Both in the performed experiments and in simulations wall mode active control is proven to be possible in both the configurations with a very reduced set of active control coils.

Published
2012
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7. Feedback control model of the m= 2,n= 1 resistive wall mode in a circular plasma

Author

M. Baruzzo, Roberto Paccagnella, Anton Soppelsa, Paolo Zanca, P. Piovesan, Tommaso Bolzonella, Piero Martin, Giuseppe Marchiori, and L. Marrelli

Subjects
Physics, STABILIZATION, Resistive touchscreen, REVERSED-FIELD PINCHES, DIII-D, Tokamak, TOKAMAKS, Feedback control, Mode (statistics), INTELLIGENT SHELL, Plasma, Mechanics, Condensed Matter Physics, Fusion, Plasmas, law.invention, Nuclear Energy and Engineering, Physics::Plasma Physics, law, Mode control, Poloidal field, Magnetohydrodynamics
Abstract

Feedback stabilization of the m = 2, n = 1 resistive wall mode in q(a) < 2 plasmas is obtained in the RFX-mod device operated as a circular tokamak. The feedback scheme implements radial sensors within the clean mode control (CMC) algorithm, a technique based on the de-aliasing of the measurements from the high periodicity sidebands produced by the coils. A cylindrical zero-pressure MHD model, which includes a realistic discrete-time description of the feedback, is able to explain the main features of the experimental observation, including the necessity of the removal of sidebands when using radial sensors. The model is also used to show that the radial field CMC presents some advantages in comparison with poloidal field based control schemes, allowing more freedom in the arrangements of the sensors.

Published
2012
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8. Internal and external electron transport barriers in the RFX-mod reversed field pinch

Author

D. F. Escande, S. Dal Bello, B. Momo, L. Zanotto, Tommaso Bolzonella, Rita Lorenzini, F. Sattin, Paolo Scarin, S. C. Guo, Alberto Alfier, L. Novello, M. Baruzzo, Alessandro Fassina, D. Bonfiglio, S. Martini, Fulvio Auriemma, Lorella Carraro, M. E. Puiatti, D. Terranova, Silvia Spagnolo, Matteo Agostini, Marco Gobbin, A. Ruzzon, Susanna Cappello, Alessandra Canton, Matteo Zuin, Emilio Martines, Giuseppe Marchiori, P. Piovesan, Roberto Paccagnella, Paolo Franz, Piero Martin, M. Valisa, Paolo Zanca, M. Veranda, M. Spolaore, E. Gazza, A. Scaggion, L. Marrelli, Italo Predebon, Sheena Menmuir, Gianluca Spizzo, P. Innocente, Federica Bonomo, R. Cavazzana, L. Piron, N. Vianello, Anton Soppelsa, G. De Masi, L. Apolloni, Barbara Zaniol, Puiatti, M, Valisa, M, Agostini, M, Auriemma, F, Bonomo, F, Carraro, L, Fassina, A, Gobbin, M, Lorenzini, R, Momo, B, Scaggion, A, Zaniol, B, Alfier, A, Apolloni, L, Baruzzo, M, Bolzonella, T, Bonfiglio, D, Canton, A, Cappello, S, Cavazzana, R, Dal Bello, S, De Masi, G, Escande, D, Franz, P, Gazza, E, Guo, S, Innocente, P, Marchiori, G, Marrelli, L, Martin, P, Martines, E, Martini, S, Menmuir, S, Novello, L, Paccagnella, R, Piovesan, P, Piron, L, Predebon, I, Ruzzon, A, Sattin, F, Scarin, P, Soppelsa, A, Spizzo, G, Spagnolo, S, Spolaore, M, Terranova, D, Veranda, M, Vianello, N, Zanca, P, Zanotto, L, and Zuin, M

Subjects
Nuclear and High Energy Physics, OHMIC H-MODE, Tokamak, Materials science, RFX-mod, Reversed field pinch, Condensed matter physics, CONFINEMENT, Plasma, reversed field pinch, Condensed Matter Physics, Electron transport chain, law.invention, Shear (sheet metal), law, Plasmas, TOKAMAK, RFP, Electron temperature, OPERATION, Internal heating, transport barrier, Bifurcation
Abstract

An interesting result of magnetic chaos reduction in RFX-mod high current discharges is the development of strong electron transport barriers. An internal heat and particle transport barrier is formed when a bifurcation process changes the magnetic configuration into a helical equilibrium and chaos reduction follows, together with the formation of a null in the q shear. Strong temperature gradients develop, corresponding to a decreased thermal and particle transport. Turbulence analysis shows that the large electron temperature gradients are limited by the onset of micro-tearing modes, in addition to residual magnetic chaos. A new type of electron transport barrier with strong temperature gradients develops more externally (r/a = 0.8) accompanied by a 30% improvement of the global confinement time. The mechanism responsible for the formation of such a barrier is still unknown but it is likely associated with a local reduction of magnetic chaos. These external barriers develop primarily in situations of well-conditioned walls so that they might be regarded as attempts towards an L–H transition. Both types of barriers occur in high-current low-collisionality regimes. Analogies with tokamak and stellarators are discussed.

Published
2011
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9. Improved dynamic response of magnetic feedback in RFX-mod and DIII-D

Author

Piero Martin, L. Piron, Lionello Marrelli, Giuseppe Marchiori, P. Piovesan, Anton Soppelsa, H. Reimerdes, Yongkyoon In, M. Okabayashi, E. J. Strait, and Jeremy Hanson

Subjects
Physics, Reversed field pinch, Magnetic energy, Electromagnet, PLASMAS, Mechanics, Condensed Matter Physics, Magnetostatics, law.invention, Nuclear magnetic resonance, DESIGN, Nuclear Energy and Engineering, Magnetic core, Electromagnetic coil, law, Physics::Plasma Physics, ACTIVE CONTROL, Magnetic pressure, Magnetic reactance
Abstract

The wall of any magnetic fusion device is characterized by the presence of several 3D structures, such as portholes for diagnostics and for heating and current drive systems, coil feeds and other features. Time-varying magnetic fields induce eddy currents in the wall, whose pattern is modified by these structures, giving rise to magnetic field errors that can be amplified or shielded by the plasma. Two examples will be given on how the dynamic response of a 3D wall to external magnetic fields can be identified and used to optimize magnetic feedback. In the RFX-mod reversed-field pinch, a dynamic decoupler algorithm has been developed, which allows for the production of pure radial magnetic field harmonics inside the wall, reducing the harmonic distortion due to the 3D wall structures. This is applied here to the problem of producing helical boundary conditions to control helical RFP equilibria. In the DIII-D tokamak, a frequency-dependent scheme for the compensation of the magnetic sensors from spurious n = 1 fields due to the coupling with the feedback and axisymmetric coils has been recently implemented in real time and tested with plasma. The possible relevance of these 3D effects for high performance scenarios is discussed. © 2011 IOP Publishing Ltd.

Published
2011
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10. 3D effects on RWM physics in RFX-mod

Author

Roberto Paccagnella, M. Baruzzo, Fabio Villone, Anton Soppelsa, Yueqiang Liu, S. C. Guo, Giuseppe Marchiori, Tommaso Bolzonella, and Zhirui Wang

Subjects
Physics, Coupling, Nuclear and High Energy Physics, Resistive touchscreen, Reversed field pinch, Plasma parameters, Mechanics, Plasma, Condensed Matter Physics, law.invention, RESISTIVE WALL MODES, symbols.namesake, Fourier transform, FEEDBACK-CONTROL, law, Physics::Plasma Physics, Harmonics, REVERSED-FIELD PINCH, Eddy current, symbols, ACTIVE CONTROL, MAGNETOHYDRODYNAMIC INSTABILITIES
Abstract

In this paper insights into the behaviour of resistive wall modes (RWMs) in the RFX-mod reversed field pinch device are given, with a focus on 3D issues in the characterization of the m spectrum of the mode and on the study of multi-harmonic coupling. In the first part of the paper the interaction between multiple unstable RWMs is studied and the presence of a coupling between different poloidal components of the most unstable RWM is demonstrated, taking advantage of the flexibility of the RFX-mod control system. In the second part of the work, the dependence of the growth rates of RWMs on a complete set of plasma parameters is studied in order to create a complete and homogeneous database, which permits a careful validation of stability codes. Finally, the experimental data are compared with the code predictions which take into account the 3D structure of conductors around the plasma. The different effects that modify the simple description, where unstable modes can be identified with single Fourier harmonics, appear to be explained by a mixture of toroidicity-induced and 3D eddy current effects.

Published
2011
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11. Overview of the RFX fusion science program

Author

M. Gobbin, Roberto Pasqualotto, D. Bonfiglio, Enrico Zilli, Giuseppe Marchiori, Piero Martin, S. Martini, Fulvio Auriemma, E. Gazza, D.K. Mansfield, P. Zaccaria, Piergiorgio Sonato, S. Ortolani, Wolf-Dieter Schneider, D. Yadikin, Stefano Munaretto, L. Piron, M. Valisa, Fabio Sattin, Susanna Cappello, G. V. Perverezev, F. Milani, Roberto Paccagnella, Paolo Bettini, S. Fiameni, Roscoe White, A. Ruzzon, V. Antoni, Leonardo Giudicotti, Yueqiang Liu, Lionello Marrelli, Nicola Vianello, S. Dal Bello, A. Scaggion, V. Rigato, Fabio Villone, A. Zamengo, Federica Bonomo, R. Cavazzana, M. Baruzzo, L. Carraro, F. Fantini, Giuseppe Zollino, Barbara Zaniol, Rita Lorenzini, Luis Chacon, X. Garbet, C. Angioni, Andrea Rizzolo, G. De Masi, G. Rostagni, W. A. Cooper, Manabu Takechi, Piero Agostinetti, Paolo Scarin, A. Pizzimenti, Yongkyoon In, Sheena Menmuir, Silvia Spagnolo, M. Moresco, Satoru Kiyama, S. P. Hirshman, M. Okabayashi, Giuseppe Chitarin, S. C. Guo, Gabriele Manduchi, Dominique Escande, Gianluigi Serianni, Alessandro Fassina, Luca Grando, Simona Barison, Allen H. Boozer, Michael Drevlak, Diego Marcuzzi, M. Pavei, J.Q. Dong, Anton Soppelsa, B. Momo, Gianluca Spizzo, Hajime Sakakita, Neil Pomphrey, Shunsuke Ide, Donald A. Spong, J. S. Sarff, Alessandra Canton, D. Lopez Bruna, M. Brombin, Matteo Zuin, T. Bolzonella, R. Piovan, Songfen Liu, Alberto Ferro, Italo Predebon, V. Igochine, L. Zanotto, Simone Peruzzo, Elena Gaio, P. Piovesan, Cesare Taliercio, J. Adamek, Go Matsunaga, P. Zanca, A. Buffa, M. Veranda, N. Pomaro, M. Spolaore, Oliviero Barana, Francesco Gnesotto, Emilio Martines, M. Dalla Palma, Paolo Franz, David Terranova, Yoichi Hirano, Matteo Agostini, G. Mazzitelli, Alberto Alfier, L. Novello, Vanni Toigo, M. Boldrin, R. Delogu, Guglielmo Rubinacci, Maria Ester Puiatti, A. Fiorentin, Karsten McCollam, E. Spada, M. Cavinato, A. De Lorenzi, L. Apolloni, J. Brotankova, F. Fellin, P. Innocente, Raul Sanchez, Zhirui Wang, Adriano Luchetta, Martin, P, Adamek, J, Agostinetti, P, Agostini, M, Alfier, A, Angioni, C, Antoni, V, Apolloni, L, Auriemma, F, Barana, O, Barison, S, Baruzzo, M, Bettini, P, Boldrin, M, Bolzonella, T, Bonfiglio, D, Bonomo, F, Boozer, A, Brombin, M, Brotankova, J, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cavinato, M, Chacon, L, Chitarin, G, Cooper, W, Dal Bello, S, Dalla Palma, M, Delogu, R, De Lorenzi, A, De Masi, G, Dong, J, Drevlak, M, Escande, D, Fantini, F, Fassina, A, Fellin, F, Ferro, A, Fiameni, S, Fiorentin, A, Franz, P, Gaio, E, Garbet, X, Gazza, E, Giudicotti, L, Gnesotto, F, Gobbin, M, Grando, L, Guo, S, Hirano, Y, Hirshman, S, Ide, S, Igochine, V, In, Y, Innocente, P, Kiyama, S, Liu, S, Liu, Y, Bruna, D, Lorenzini, R, Luchetta, A, Manduchi, G, Mansfield, D, Marchiori, G, Marcuzzi, D, Marrelli, L, Martini, S, Matsunaga, G, Martines, E, Mazzitelli, G, Mccollam, K, Menmuir, S, Milani, F, Momo, B, Moresco, M, Munaretto, S, Novello, L, Okabayashi, M, Ortolani, S, Paccagnella, R, Pasqualotto, R, Pavei, M, Perverezev, G, Peruzzo, S, Piovan, R, Piovesan, P, Piron, L, Pizzimenti, A, Pomaro, N, Pomphrey, N, Predebon, I, Puiatti, M, Rigato, V, Rizzolo, A, Rostagni, G, Rubinacci, G, Ruzzon, A, Sakakita, H, Sanchez, R, Sarff, J, Sattin, F, Scaggion, A, Scarin, P, Schneider, W, Serianni, G, Sonato, P, Spada, E, Soppelsa, A, Spagnolo, S, Spolaore, M, Spong, D, Spizzo, G, Takechi, M, Taliercio, C, Terranova, D, Toigo, V, Valisa, M, Veranda, M, Vianello, N, Villone, F, Wang, Z, White, R, Yadikin, D, Zaccaria, P, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zollino, G, Zuin, M, Martin, P., Adamek, J., Agostinetti, P., Agostini, M., Alfier, A., Angioni, C., Antoni, V., Apolloni, L., Auriemma, F., Barana, O., Barison, S., Baruzzo, M., Bettini, P., Boldrin, M., Bolzonella, T., Bonfiglio, D., Bonomo, F., Boozer, A. H., Brombin, M., Brotankova, J., Buffa, A., Canton, A., Cappello, S., Carraro, L., Cavazzana, R., Cavinato, M., Chacon, L., Chitarin, G., Cooper, W. A., Bello, S. D., Palma, M. D., Delogu, R., Lorenzi, A. D., Masi, G. D., Dong, J. Q., Drevlak, M., Escande, D. F., Fantini, F., Fassina, A., Fellin, F., Ferro, A., Fiameni, S., Fiorentin, A., Franz, P., Gaio, E., Garbet, X., Gazza, E., Giudicotti, L., Gnesotto, F., Gobbin, M., Grando, L., Guo, S. C., Hirano, Y., Hirshman, S. P., Ide, S., Igochine, V., In, Y., Innocente, P., Kiyama, S., Liu, S. F., Liu, Y. Q., Bruna, D. L., Lorenzini, R., Luchetta, A., Manduchi, G., Mansfield, D. K., Marchiori, G., Marcuzzi, D., Marrelli, L., Martini, S., Matsunaga, G., Martines, E., Mazzitelli, G., Mccollam, K., Menmuir, S., Milani, F., Momo, B., Moresco, M., Munaretto, S., Novello, L., Okabayashi, M., Ortolani, S., Paccagnella, R., Pasqualotto, R., Pavei, M., Perverezev, G. V., Peruzzo, S., Piovan, R., Piovesan, P., Piron, L., Pizzimenti, A., Pomaro, N., Pomphrey, N., Predebon, I., Puiatti, M. E., Rigato, V., Rizzolo, A., Rostagni, G., Rubinacci, Guglielmo, Ruzzon, A., Sakakita, H., Sanchez, R., Sarff, J. S., Sattin, F., Scaggion, A., Scarin, P., Schneider, W., Serianni, G., Sonato, P., Spada, E., Soppelsa, A., Spagnolo, S., Spolaore, M., Spong, D. A., Spizzo, G., Takechi, M., Taliercio, C., Terranova, D., Toigo, V., Valisa, M., Veranda, M., Vianello, N., Villone, F., Wang, Z., White, R. B., Yadikin, D., Zaccaria, P., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zilli, E., Zollino, G., and Zuin, M.

Subjects
Nuclear and High Energy Physics, RFX-mod, Tokamak, Nuclear engineering, PLASMAS, CONFINEMENT, reversed field pinch, magnetic confinement, law.invention, law, Physics::Plasma Physics, RFP, Scaling, Mod, Physics, Reversed field pinch, STABILITY, Magnetic confinement fusion, INTERNAL TRANSPORT BARRIER, Plasma, Fusion power, Condensed Matter Physics, REVERSED-FIELD-PINCH, Atomic physics, Magnetohydrodynamics, Stellarator
Abstract

This paper summarizes the main achievements of the RFX fusion science program in the period between the 2008 and 2010 IAEA Fusion Energy Conferences. RFX-mod is the largest reversed field pinch in the world, equipped with a system of 192 coils for active control of MHD stability. The discovery and understanding of helical states with electron internal transport barriers and core electron temperature >1.5 keV significantly advances the perspectives of the configuration. Optimized experiments with plasma current up to 1.8 MA have been realized, confirming positive scaling. The first evidence of edge transport barriers is presented. Progress has been made also in the control of first-wall properties and of density profiles, with initial first-wall lithization experiments. Micro-turbulence mechanisms such as ion temperature gradient and micro-tearing are discussed in the framework of understanding gradient-driven transport in low magnetic chaos helical regimes. Both tearing mode and resistive wall mode active control have been optimized and experimental data have been used to benchmark numerical codes. The RFX programme also provides important results for the fusion community and in particular for tokamaks and stellarators on feedback control of MHD stability and on three-dimensional physics. On the latter topic, the result of the application of stellarator codes to describe three-dimensional reversed field pinch physics will be presented. © 2011 IAEA, Vienna.

Published
2011
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12. Resistive wall mode control code maturity: progress and specific examples

Author

A.M. Garofalo, H. Reimerdes, M.J. Lanctot, Guglielmo Rubinacci, Yueqiang Liu, Ming-Sheng Chu, Tommaso Bolzonella, Roberto Paccagnella, Raffaele Albanese, G.L. Jackson, I. T. Chapman, R.J. La Haye, Wenfeng Guo, Alfredo Pironti, Anton Soppelsa, T. C. Hender, M. Baruzzo, M. Furno Palumbo, Giuseppe Marchiori, Salvatore Ventre, R. J. Hastie, Fabio Villone, C. G. Gimblett, E. J. Strait, M. Okabayashi, D. Yadykin, G. Ambrosino, Yongkyoon In, Yueqiang, Liu, Chu, M. S., Guo, W. F., Villone, F., Albanese, Raffaele, Ambrosino, Giuseppe, Baruzzo, M., Bolzonella, T., Chapman, I. T., Garofalo, A. M., Gimblett, C. G., Hastie, R. J., Hender, T. C., Jackson, G. L., La Haye, R. J., Lanctot, M. J., In, Y., Marchiori, G., Okabayashi, M., Paccagnella, R., Furno Palumbo, M., Pironti, Alfredo, Reimerdes, H., Rubinacci, Guglielmo, Soppelsa, A., Strait, E. J., Ventre, S., and Yadykin, D.

Subjects
Tokamak, TOKAMAKS, Magnetohydrodynamic and fluid equation, PLASMAS, MARS-k, Blanket, Stability (probability), law.invention, Plasma rwm MHD, MHD STABILITY, law, Carma code, ITER, RFX, Physics, Resistive touchscreen, Steady state, Mode (statistics), FEEDBACK STABILIZATION, Mechanics, Condensed Matter Physics, Nuclear Energy and Engineering, Macroinstabilitie, Magnetohydrodynamics, Reduction (mathematics)
Abstract

Two issues of the resistive wall mode (RWM) control code maturity are addressed: the inclusion of advanced mode damping physics beyond the ideal MHD description, and the possibility of taking into account the influence of 3D features of the conducting structures on the mode stability and control. Examples of formulations and computational results are given, using the MARS-F/K codes and the CarMa code. The MARS-K calculations for a DIII-D plasma shows that the fast ion contributions, which can give additional drift kinetic stabilization in the perturbative approach, also drive an extra unstable branch of mode in the self-consistent kinetic modelling. The CarMa modelling for the ITER steady state advanced plasmas shows about 20% reduction in the RWM growth rate by the volumetric blanket modules. The multi-mode analysis predicts a weak interaction between the n = 0 and the n = 1 RWMs, due to the 3D ITER walls. The CarMa code is also successfully applied to model the realistic feedback experiments in RFX.

Published
2010
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13. Overview of RFX-mod results

Author

R. Paccagnella, Cesare Taliercio, J. Adamek, V. Antoni, A. Pizzimenti, Gianluca Spizzo, Gabriele Manduchi, E. Spada, Vanni Toigo, D. Terranova, Alberto Ferro, N. Pomaro, P. Zaccaria, Rita Lorenzini, B. E. Chapman, Piero Martin, L. Guazzotto, A. Zamengo, Simone Peruzzo, Elena Gaio, Italo Predebon, V. Igochine, F. Milani, M. Spolaore, Oliviero Barana, Francesco Gnesotto, Alessandro Fassina, Giuseppe Marchiori, E. Gazza, G. Serianni, L. Zanotto, Piergiorgio Sonato, L. Piron, A. De Lorenzi, Diego Marcuzzi, Alessandra Canton, Matteo Zuin, T. Bolzonella, Federica Bonomo, Fabio Villone, M. Valisa, S. Cappello, H. Zohm, R. Cavazzana, J. Brotankova, Maria Ester Puiatti, M. Gobbin, P. Scarin, P. Zanca, Silvia Spagnolo, M. Baruzzo, Lionello Marrelli, Fabio Sattin, A. Buffa, Nicola Vianello, Fulvio Auriemma, Karsten McCollam, S. Ortolani, J. S. Sarff, S. Dal Bello, M. Cavinato, Paolo Bettini, P. Piovesan, G. Rostagni, P. Innocente, P. Buratti, M. Moresco, Roscoe White, Leonardo Giudicotti, Anton Soppelsa, Guglielmo Rubinacci, Sheena Menmuir, Emilio Martines, Paolo Franz, L. Carraro, D. Bonfiglio, Enrico Zilli, S. Martini, G. De Masi, L. Apolloni, Giuseppe Chitarin, M. Brombin, R. Piovan, Matteo Agostini, J.A. Reusch, Barbara Zaniol, Yueqiang Liu, S. C. Guo, Dominique Escande, S.V. Annibaldi, Alberto Alfier, L. Novello, Luca Grando, Adriano Luchetta, Roberto Pasqualotto, D. Yadikin, Martin, P, Apolloni, L, Puiatti, M, Adamek, J, Agostini, M, Alfier, A, Annibaldi, S, Antoni, V, Auriemma, F, Barana, O, Baruzzo, M, Bettini, P, Bolzonella, T, Bonfiglio, D, Bonomo, F, Brombin, M, Brotankova, J, Buffa, A, Buratti, P, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Cavinato, M, Chapman, B, Chitarin, G, Dal Bello, S, De Lorenzi, A, De Masi, G, Escande, D, Fassina, A, Ferro, A, Franz, P, Gaio, E, Gazza, E, Giudicotti, L, Gnesotto, F, Gobbin, M, Grando, L, Guazzotto, L, Guo, S, Igochine, V, Innocente, P, Liu, Y, Lorenzini, R, Luchetta, A, Manduchi, G, Marchiori, G, Marcuzzi, D, Marrelli, L, Martini, S, Martines, E, Mccollam, K, Menmuir, S, Milani, F, Moresco, M, Novello, L, Ortolani, S, Paccagnella, R, Pasqualotto, R, Peruzzo, S, Piovan, R, Piovesan, P, Piron, L, Pizzimenti, A, Pomaro, N, Predebon, I, Reusch, J, Rostagni, G, Rubinacci, G, Sarff, J, Sattin, F, Scarin, P, Serianni, G, Sonato, P, Spada, E, Soppelsa, A, Spagnolo, S, Spolaore, M, Spizzo, G, Taliercio, C, Terranova, D, Toigo, V, Valisa, M, Vianello, N, Villone, F, White, R, Yadikin, D, Zaccaria, P, Zamengo, A, Zanca, P, Zaniol, B, Zanotto, L, Zilli, E, Zohm, H, Zuin, M, Martin, P., Apolloni, L., Puiatti, M. E., Adamek, J., Agostini, M., Alfier, A., Annibaldi, S. V., Antoni, V., Auriemma, F., Barana, O., Baruzzo, M., Bettini, P., Bolzonella, T., Bonfiglio, D., Bonomo, F., Brombin, M., Brotankova, J., Buffa, A., Buratti, P., Canton, A., Cappello, S., Carraro, L., Cavazzana, R., Cavinato, M., Chapman, B. E., Chitarin, G., Dal Bello, S., De Lorenzi, A., De Masi, G., Escande, D. F., Fassina, A., Ferro, A., Franz, P., Gaio, E., Gazza, E., Giudicotti, L., Gnesotto, F., Gobbin, M., Grando, L., Guazzotto, L., Guo, S. C., Igochine, V., Innocente, P., Liu, Y. Q., Lorenzini, R., Luchetta, A., Manduchi, G., Marchiori, G., Marcuzzi, D., Marrelli, L., Martini, S., Martines, E., Mccollam, K., Menmuir, S., Milani, F., Moresco, M., Novello, L., Ortolani, S., Paccagnella, R., Pasqualotto, R., Peruzzo, S., Piovan, R., Piovesan, P., Piron, L., Pizzimenti, A., Pomaro, N., Predebon, I., Reusch, J. A., Rostagni, G., Rubinacci, Guglielmo, Sarff, J. S., Sattin, F., Scarin, P., Serianni, G., Sonato, P., Spada, E., Soppelsa, A., Spagnolo, S., Spolaore, M., Spizzo, G., Taliercio, C., Terranova, D., Toigo, V., Valisa, M., Vianello, N., Villone, F., White, R. B., Yadikin, D., Zaccaria, P., Zamengo, A., Zanca, P., Zaniol, B., Zanotto, L., Zilli, E., Zohm, H., and Zuin, M.

Subjects
Physics, Nuclear and High Energy Physics, Leading edge, Tokamak, RFX-mod, Reversed field pinch, MHD, magnetic confinement, Magnetic confinement fusion, reversed field pinch, Fusion power, Condensed Matter Physics, TRANSPORT, law.invention, LUNDQUIST NUMBER, Nuclear physics, REVERSED-FIELD-PINCH, EDGE, law, RFP, Electron temperature, Magnetohydrodynamics, Plasma stability
Abstract

With the exploration of the MA plasma current regime in up to 0.5 s long discharges, RFX-mod has opened new and very promising perspectives for the reversed field pinch (RFP) magnetic configuration, and has made significant progress in understanding and improving confinement and in controlling plasma stability. A big leap with respect to previous knowledge and expectations on RFP physics and performance has been made by RFX-mod since the last 2006 IAEA Fusion Energy Conference. A new self-organized helical equilibrium has been experimentally achieved (the Single Helical Axis - SHAx - state), which is the preferred state at high current. Strong core electron transport barriers characterize this regime, with electron temperature gradients comparable to those achieved in tokamaks, and by a factor of 4 improvement in confinement time with respect to the standard RFP. RFX-mod is also providing leading edge results on real-time feedback control of MHD instabilities, of general interest for the fusion community. © 2009 IAEA, Vienna.

Published
2009
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14. Helical equilibria and magnetic structures in the reversed field pinch and analogies to the tokamak and stellarator

Author

Stefano Munaretto, L. Carraro, Alessandra Canton, S. Dal Bello, Matteo Zuin, A. Pizzimenti, D. Bonfiglio, S. Martini, V. Antoni, Elena Gaio, Fulvio Auriemma, Lionello Marrelli, Fabio Sattin, B. Momo, Tommaso Bolzonella, Nicola Vianello, L. Apolloni, Emilio Martines, Gianluca Spizzo, M. Baruzzo, R. Delogu, Paolo Franz, Susanna Cappello, P. Piovesan, Italo Predebon, M. Moresco, Rita Lorenzini, Leonardo Giudicotti, L. Novello, Sheena Menmuir, Paolo Scarin, P. Zanca, Anton Soppelsa, Luca Grando, G. De Masi, M. Spolaore, Giuseppe Marchiori, Roberto Pasqualotto, Neil Pomphrey, S. C. Guo, David Terranova, A. Zamengo, P. Innocente, Maria Ester Puiatti, Piero Martin, E. Gazza, Dominique Escande, Alberto Alfier, Allen H. Boozer, M. Valisa, L. Piron, Matteo Agostini, Barbara Zaniol, M. Brombin, R. Piovan, L. Zanotto, E. Spada, Gabriele Manduchi, Gianluigi Serianni, Alessandro Fassina, Roberto Paccagnella, Federica Bonomo, R. Cavazzana, Silvia Spagnolo, Cesare Taliercio, M. Gobbin, Puiatti, M, Alfier, A, Auriemma, F, Cappello, S, Carraro, L, Cavazzana, R, Dal Bello, S, Fassina, A, Escande, D, Franz, P, Gobbin, M, Innocente, P, Lorenzini, R, Marrelli, L, Martin, P, Piovesan, P, Predebon, I, Sattin, F, Spizzo, G, Terranova, D, Valisa, M, Zaniol, B, Zanotto, L, Zuin, M, Agostini, M, Antoni, V, Apolloni, L, Baruzzo, M, Bolzonella, T, Bonfiglio, D, Bonomo, F, Boozer, A, Brombin, M, Canton, A, Delogu, R, De Masi, G, Gaio, E, Gazza, E, Giudicotti, L, Grando, L, Guo, S, Manduchi, G, Marchiori, G, Martines, E, Martini, S, Menmuir, S, Momo, B, Moresco, M, Munaretto, S, Novello, L, Paccagnella, R, Pasqualotto, R, Piovan, R, Piron, L, Pizzimenti, A, Pomphrey, N, Scarin, P, Serianni, G, Spada, E, Soppelsa, A, Spagnolo, S, Spolaore, M, Taliercio, C, Vianello, N, Zamengo, A, and Zanca, P

Subjects
Physics, Tokamak, RFX-mod, Reversed field pinch, Field (physics), Condensed matter physics, Magnetic confinement fusion, reversed field pinch, Edge (geometry), SELF-ORGANIZATION, Condensed Matter Physics, law.invention, Core (optical fiber), quasi-single helicity, INTERNAL TRANSPORT BARRIERS, MHD ACTIVE CONTROL, Nuclear Energy and Engineering, law, RFP, QSH, plasma equilibrium, Atomic physics, Pressure gradient, Stellarator
Abstract

The reversed field pinch configuration is characterized by the presence of magnetic structures both in the core and at the edge: in the core, at high plasma current the spontaneous development of a helical structure is accompanied by the appearance of internal electron transport barriers; at the edge strong pressure gradients, identifying an edge transport barrier, are observed too, related to the position of the field reversal surface. The aim of this paper is the experimental characterization of both the internal and edge transport barriers in relation to the magnetic topology, discussing possible analogies and differences with other confinement schemes. © 2009 IOP Publishing Ltd.

Published
2009
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15. Feedback control of resistive wall modes by saddle coils in RFX-mod

Author

Gabriele Manduchi, Roberto Paccagnella, P. Zanca, Luca Grando, Lionello Marrelli, Tommaso Bolzonella, Adriano Luchetta, Anton Soppelsa, M. Cavinato, Giuseppe Marchiori, and Elena Gaio

Subjects
Physics, Resistive touchscreen, Tokamak, Toroid, Mechanical Engineering, Torus, Resistive wall modes, Mechanics, Fusion power, Feedback control, law.invention, MHD mode control, Nuclear Energy and Engineering, law, Control system, Digital control system, General Materials Science, Digital control, Saddle, Civil and Structural Engineering
Abstract

Active control of resistive wall modes (RWMs) is a key issue for high-beta operation of future tokamaks, including ITER. RFX has been recently modified to specifically address this issue by means of a new saddle coil system, which is the most powerful and flexible among all fusion devices, including 192 coils covering the whole torus. Unstable RWMs have been experimentally observed during the recent machine operation, showing poloidal and toroidal components m = 1, 2 < |n| < 7 and growth times of some tens of ms, consistent with theoretical predictions. RFX-mod addresses the control of RWMs by acting on the magnetic field configuration at the plasma boundary. The system aims not only at RWM stabilization, but also at interaction with tearing modes. By means of the system, successful experimental campaigns have been executed demonstrating the feasibility of RWM active control. The paper discusses on the system engineering and technological features and presents the results achieved.

Published
2007
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16. Physics and Control of External Kink Instabilities with Realistic 3D Boundaries: a Challenge for Modern Experiments and Modeling

Author

Tommaso Bolzonella, Go Matsunaga, L. Pigatto, Anton Soppelsa, Fabio Villone, Manabu Takechi, M. Baruzzo, Giuseppe Marchiori, and Yueqiang Liu

Subjects
Physics, Tokamak, Reversed field pinch, MHD stability, Mechanics, Kink instability, Condensed Matter Physics, Instability, Finite element method, 3D modeling, law.invention, Magnetic field, Physics::Plasma Physics, MHD feedback control, law, Boundary value problem, Actuator, FEM modeling, tokamak, Resistive Wall Modes, Reversed Field Pinch
Abstract

In present day devices, the external kink ideal MHD instability establishes hard operational boundaries for both the tokamak and the Reversed Field Pinch (RFP) configurations. An interesting feature of it is that its growth rate critically depends on the device passive boundary characteristics and this can slow it down to time scales accessible to modern real time feedback control systems, normally using external active coils as actuators. 3D passive structures and external fields play a key role in determining physics and control of this instability. This is in particular true for equilibria with multimodal unstable RWM spectra where modes can couple to specific 3D features of passive and active magnetic boundary. In the paper we will present recent data and simulations from RFX-mod, a medium size (R = 2 m, a = 0.459 m) device able to confine RFP and tokamak plasmas with currents up to 2 MA and 120 kA, respectively. Successful quantitative modeling of multimodal RWM control experiments performed using different actuator configurations will be presented and commented.

Published
2014
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17. Overview of the RFX-mod fusion science programme

Author

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

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

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

Published
2013
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18. Dynamic decoupling and multi-mode magnetic feedback for error field correction in RFX-mod

Author

D. Terranova, L. Marrelli, L. Piron, P. Piovesan, Giuseppe Marchiori, Luca Grando, and Anton Soppelsa

Subjects
RESISTIVE-WALL MODES, Physics, Nuclear and High Energy Physics, ACTIVE MHD CONTROL, LOCKING, PINCH, Demagnetizing field, TEARING MODES, Condensed Matter Physics, Magnetic field, Computational physics, law.invention, Nuclear magnetic resonance, Physics::Plasma Physics, law, Harmonics, Eddy current, Pinch, Waveform, Magnetic reactance, Decoupling (electronics)
Abstract

Magnetic field errors can have a significant impact on the confinement properties of magnetized fusion plasmas. In the RFX-mod reversed-field pinch (Sonato et al 2003 Fusion Eng. Des. 33 161) a significant error field is produced during the current ramp by the eddy currents induced in the 3D wall structures, such as the gaps and some large portholes, by the temporal variation of the vertical magnetic field. A set of 192 magnetic sensors and 192 active coils allowed accurate identification of the error field spatiotemporal pattern and its correction. The correction scheme combines pre-programmed current waveforms and multi-mode magnetic feedback. The pre-programmed currents were computed with the dynamic decoupling algorithm developed in Soppelsa et al (2008 Fusion Eng. Des. 83 224). This accounts for the mutual interaction between different feedback coils and magnetic sensors, which is affected by the frequency-dependent response of the 3D wall structures to external magnetic fields. At the same time, multi-mode magnetic feedback is applied to the main error field harmonics. During the current ramp, multiple tearing modes are normally phase-locked and produce a toroidally localized deformation of the plasma column that tends to grow where the error fields are larger. With error field correction, this deformation does not grow at preferred positions, thus avoiding the plasma–wall interaction being too localized there. In general, the decoupling approach used in this work may find applications in other machines.

Published
2011
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19. Improvement of the magnetic configuration in the reversed field pinch through successive bifurcations

Author

Roberto Pasqualotto, M. Spolaore, Oliviero Barana, Francesco Gnesotto, S. Ortolani, C. Taliercio, Alberto Alfier, L. Novello, Anton Soppelsa, Pierluigi Veltri, D. Terranova, Enrico Zilli, S. Martini, Piergiorgio Sonato, Simone Peruzzo, Elena Gaio, Susanna Cappello, Piero Martin, Giuseppe Chitarin, Matteo Agostini, R. Piovan, S. Dal Bello, Vanni Toigo, D. F. Escande, Alessandro Fassina, M. Brombin, Silvia Spagnolo, V. Antoni, P. Piovesan, Paolo Bettini, Luca Grando, Rita Lorenzini, Gabriele Manduchi, Roberto Paccagnella, Paolo Scarin, N. Pomaro, Paolo Innocente, E. Gazza, Daniele Bonfiglio, Italo Predebon, Federica Bonomo, M. Baruzzo, G. De Masi, Barbara Zaniol, M. E. Puiatti, Adriano Luchetta, Lorella Carraro, Giuseppe Marchiori, Emilio Martines, Marco Gobbin, M. Valisa, G. Serianni, Paolo Franz, M. Moresco, S. C. Guo, Leonardo Giudicotti, Lionello Marrelli, Tommaso Bolzonella, A. Buffa, F. Sattin, Roberto Cavazzana, G. Rostagni, E. Spada, L. Zanotto, Fulvio Auriemma, L. Piron, N. Vianello, L. Apolloni, Alessandra Canton, Matteo Zuin, A. Pizzimenti, F. Milani, A. De Lorenzi, Diego Marcuzzi, Gianluca Spizzo, P. Zaccaria, Lorenzini, R, Agostini, M, Alfier, A, Antoni, V, Apolloni, L, Auriemma, F, Barana, O, Baruzzo, M, Bettini, P, Bonfiglio, D, Bolzonella, T, Bonomo, F, Brombin, M, Buffa, A, Canton, A, Cappello, S, Carraro, L, Cavazzana, R, Chitarin, G, Dal Bello, S, De Lorenzi, A, De Masi, G, Escande, D, Fassina, A, Franz, P, Gaio, E, Gazza, E, Giudicotti, L, Gnesotto, F, Gobbin, M, Grando, L, Guo, S, Innocente, P, Luchetta, A, Manduchi, G, Marchiori, G, Marcuzzi, D, Marrelli, L, Martin, P, Martini, S, Martines, E, Milani, F, Moresco, M, Novello, L, Ortolani, S, Paccagnella, R, Pasqualotto, R, Peruzzo, S, Piovan, R, Piovesan, P, Piron, L, Pizzimenti, A, Pomaro, N, Predebon, I, Puiatti, M, Rostagni, G, Sattin, F, Scarin, P, Serianni, G, Sonato, P, Spada, E, Soppelsa, A, Spagnolo, S, Spizzo, G, Spolaore, M, Taliercio, C, Terranova, D, Toigo, V, Valisa, M, Veltri, P, Vianello, N, Zaccaria, P, Zaniol, B, Zanotto, L, Zilli, E, and Zuin, M

Subjects
Self-organization, magnetic configuration, Physics, RFX-mod, Tokamak, Reversed field pinch, MHD, magnetic confinement, Perturbation (astronomy), Saddle-node bifurcation, reversed field pinch, Plasma, Mechanics, Condensed Matter Physics, law.invention, quasi-single helicity, Nuclear magnetic resonance, Amplitude, Physics::Plasma Physics, law, bifurcation, RFP, QSH, Plasma stability, Bifurcation
Abstract

The reversed field pinch (RFP) is a magnetic configuration alternative to the tokamak that can be considered for a second generation of reactors. In this paper new remarkable results obtained in the RFP experiment RFX-mod are presented, showing that an internal transport barrier delimitates a large fraction of the plasma volume in a RFP when the current is raised to ∼1.5 MA. The formation of this transport barrier is related to a profound, spontaneous modification of the magnetic topology. Due to the occurrence of a saddle node bifurcation the plasma enters in the single helical axis state, which is theoretically known to be more resilient to chaos. This bifurcation is driven by the amplitude of the helical perturbation which dominates the mode spectrum. © 2009 American Institute of Physics.

Published
2009
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