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1,150 results on '"Cavazzana R."'

1. Lessons learned after three years of SPIDER operation and the first MITICA integrated tests

Author

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

Subjects
Physics - Plasma Physics, Physics - Accelerator Physics
Abstract

ITER envisages the use of two heating neutral beam injectors plus an optional one as part of the auxiliary heating and current drive system. The 16.5 MW expected neutral beam power per injector is several notches higher than worldwide existing facilities. A Neutral Beam Test Facility (NBTF) was established at Consorzio RFX, exploiting the synergy of two test beds, SPIDER and MITICA. SPIDER is dedicated to developing and characterizing large efficient negative ion sources at relevant parameters in ITER-like conditions: source and accelerator located in the same vacuum where the beam propagates, immunity to electromagnetic interferences of multiple radio-frequency (RF) antennas, avoidance of RF-induced discharges on the outside of the source. Three years of experiments on SPIDER have addressed to the necessary design modifications to enable full performances. The source is presently under a long shut-down phase to incorporate learnings from the experimental campaign. Parallelly, developments on MITICA, the full-scale prototype of the ITER NBI featuring a 1 MV accelerator and ion neutralization, are underway including manufacturing of in-vessel components, while power supplies and auxiliary plants are already under final testing and commissioning. Integration, commissioning and tests of the 1MV power supplies are essential for this first-of-kind system, unparalleled both in research and industry field. The integrated test to confirm 1MV output by combining invertor systems, DC generators and transmission lines extracted errors/accidents in some components. To realize a concrete system for ITER, solutions for the repair and the improvement of the system were developed. Hence, NBTF is emerging as a necessary facility, due to the large gap with existing injectors, effectively dedicated to identify issues and find solutions to enable successful ITER NBI operations in a time bound fashion.

Published
2023
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2. Numerical and experimental investigations of a microwave interferometer for the negative ion source SPIDER

Author

Agnello, R., Cavazzana, R., Furno, I., Jacquier, R., Pasqualotto, R., Sartori, E., and Serianni, G.

Subjects
Physics - Plasma Physics
Abstract

The electron density close to the extraction grids and the co-extracted electrons represent a crucial issue when operating negative ion sources for fusion reactors. An excessive electron density in the plasma expansion region can indeed inhibit the negative ion production and introduce potentially harmful electrons in the accelerator. Among the set of plasma and beam diagnostics proposed for SPIDER upgrade, a heterodyne microwave (mw) interferometer at 100 GHz is being explored as a possibility to measure electron density in the plasma extraction region. The major issue in applying this technique in SPIDER is the poor accessibility of the probing microwave beam through the source metal walls and the long distance of 4 m at which mw modules should be located outside the vacuum vessel. Numerical investigations in a full-scale geometry showed that the power transmitted through the plasma source apertures was sufficient for the microwave module sensitivity. An experimental proof-of-principle of the setup was then performed. The microwave system was tested on an experimental full-scale test-bench mimicking SPIDER viewports accessibility constraints, including the presence of a SPIDER-like plasma. The outcome of first tests revealed that, despite the geometrical constraints, in certain conditions, the electron density measurements are possible. The main issue arises from decoupling the one-pass signal from spurious multipaths generated by mw beam reflections, requiring signal cross correlation analysis. These preliminary tests demonstrate that despite the 4 m distance between the mw modules and the presence of metal walls, plasma density measurement is possible when the 80-mm diameter ports are available. In this contribution, we discuss the numerical simulations, the preliminary experimental tests and suggest design upgrades of the interferometric setup to enhance signal transmission.

Published
2023
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6. Diagnostic data integration using deep neural networks for real-time plasma analysis

Author

Garola, A. Rigoni, Cavazzana, R., Gobbin, M., Delogu, R. S., Manduchi, G., Taliercio, C., and Luchetta, A.

Subjects
Physics - Computational Physics, Computer Science - Machine Learning, Nonlinear Sciences - Adaptation and Self-Organizing Systems, 60G35, I.2.1
Abstract

Recent advances in acquisition equipment is providing experiments with growing amounts of precise yet affordable sensors. At the same time an improved computational power, coming from new hardware resources (GPU, FPGA, ACAP), has been made available at relatively low costs. This led us to explore the possibility of completely renewing the chain of acquisition for a fusion experiment, where many high-rate sources of data, coming from different diagnostics, can be combined in a wide framework of algorithms. If on one hand adding new data sources with different diagnostics enriches our knowledge about physical aspects, on the other hand the dimensions of the overall model grow, making relations among variables more and more opaque. A new approach for the integration of such heterogeneous diagnostics, based on composition of deep variational autoencoders, could ease this problem, acting as a structural sparse regularizer. This has been applied to RFX-mod experiment data, integrating the soft X-ray linear images of plasma temperature with the magnetic state. However to ensure a real-time signal analysis, those algorithmic techniques must be adapted to run in well suited hardware. In particular it is shown that, attempting a quantization of neurons transfer functions, such models can be modified to create an embedded firmware. This firmware, approximating the deep inference model to a set of simple operations, fits well with the simple logic units that are largely abundant in FPGAs. This is the key factor that permits the use of affordable hardware with complex deep neural topology and operates them in real-time., Comment: Proceeding of the 22nd IEEE Real Time Conference

Published
2020
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7. RFX-mod2 diagnostic capability enhancements for the exploration of multi-magnetic-configurations

Author

Carraro, L, Zuin, M, Abate, D, Agostinetti, P, Agostini, M, Aprile, D, Barbisan, M, Belpane, A, Berton, G, Bonotto, M, Brombin, M, Cavazzana, R, Cinnirella, L, Ciufo, S, Croci, G, Cordaro, L, D'Isa, F, Dal Bello, S, Dal Molin, A, De Masi, G, Emma, G, Fadone, M, Fassina, A, Fiorucci, D, Franz, P, Grando, L, Guiotto, F, La Matina, M, Marchiori, G, Marconato, N, Mario, I, Marrelli, L, Milazzo, R, Molisani, S, Moresco, M, Muraro, A, Perelli Cippo, E, Peruzzo, S, Porcu, P, Pomaro, N, Puiatti, M, Putignano, O, Rigamonti, D, Rigoni Garola, A, Rizzolo, A, Ruffini, F, Scarin, P, Spagnolo, S, Spolaore, M, Taliercio, C, Tardocchi, M, Terranova, D, Ugoletti, M, Valisa, M, Vianello, N, Zaniol, B, Carraro L., Zuin M., Abate D., Agostinetti P., Agostini M., Aprile D., Barbisan M., Belpane A., Berton G., Bonotto M., Brombin M., Cavazzana R., Cinnirella L., Ciufo S., Croci G., Cordaro L., D'Isa F., Dal Bello S., Dal Molin A., De Masi G., Emma G., Fadone M., Fassina A., Fiorucci D., Franz P., Grando L., Guiotto F., La Matina M., Marchiori G., Marconato N., Mario I., Marrelli L., Milazzo R., Molisani S., Moresco M., Muraro A., Perelli Cippo E., Peruzzo S., Porcu P., Pomaro N., Puiatti M. E., Putignano O., Rigamonti D., Rigoni Garola A., Rizzolo A., Ruffini F., Scarin P., Spagnolo S., Spolaore M., Taliercio C., Tardocchi M., Terranova D., Ugoletti M., Valisa M., Vianello N., Zaniol B., Carraro, L, Zuin, M, Abate, D, Agostinetti, P, Agostini, M, Aprile, D, Barbisan, M, Belpane, A, Berton, G, Bonotto, M, Brombin, M, Cavazzana, R, Cinnirella, L, Ciufo, S, Croci, G, Cordaro, L, D'Isa, F, Dal Bello, S, Dal Molin, A, De Masi, G, Emma, G, Fadone, M, Fassina, A, Fiorucci, D, Franz, P, Grando, L, Guiotto, F, La Matina, M, Marchiori, G, Marconato, N, Mario, I, Marrelli, L, Milazzo, R, Molisani, S, Moresco, M, Muraro, A, Perelli Cippo, E, Peruzzo, S, Porcu, P, Pomaro, N, Puiatti, M, Putignano, O, Rigamonti, D, Rigoni Garola, A, Rizzolo, A, Ruffini, F, Scarin, P, Spagnolo, S, Spolaore, M, Taliercio, C, Tardocchi, M, Terranova, D, Ugoletti, M, Valisa, M, Vianello, N, Zaniol, B, Carraro L., Zuin M., Abate D., Agostinetti P., Agostini M., Aprile D., Barbisan M., Belpane A., Berton G., Bonotto M., Brombin M., Cavazzana R., Cinnirella L., Ciufo S., Croci G., Cordaro L., D'Isa F., Dal Bello S., Dal Molin A., De Masi G., Emma G., Fadone M., Fassina A., Fiorucci D., Franz P., Grando L., Guiotto F., La Matina M., Marchiori G., Marconato N., Mario I., Marrelli L., Milazzo R., Molisani S., Moresco M., Muraro A., Perelli Cippo E., Peruzzo S., Porcu P., Pomaro N., Puiatti M. E., Putignano O., Rigamonti D., Rigoni Garola A., Rizzolo A., Ruffini F., Scarin P., Spagnolo S., Spolaore M., Taliercio C., Tardocchi M., Terranova D., Ugoletti M., Valisa M., Vianello N., and Zaniol B.

Abstract

The RFX-mod2 device, the upgraded version of the previous RFX-mod with a modified magnetic boundary, is presently under realization and will start to be operated in 2025. Significant upgrades of the diagnostic capabilities have been proposed and are under development. These include a largely increased number of in-vessel magnetic and electrostatic sensors, a new fast reciprocating manipulator for the exploration of the edge plasma in a wide range of experimental conditions, the improved Thomson scattering and soft x-ray diagnostics system for a detailed determination of the behavior of the electron temperature profile, new dedicated systems for the space and time resolved analysis of x-ray spectra and neutron rate, a reflectometric diagnostic for real-time determination of plasma position, two diagnostics devoted to the imaging of light impurities and influxes behavior along with arrays of halo current sensors. These diagnostic upgrades will be accompanied by a significant effort to improve the control of the electron density and of the impurity influxes by means of proper treatment of plasma facing components with in-vessel fixed electrodes distributed over the first wall. The described advancements will allow a deeper understanding of physics phenomena in the wide variety of magnetic configurations, including the tokamak, the reversed-field pinch and the Ultra-low q, which can be produced in RFX-mod2 thanks to its flexibility and unique MHD control capabilities.

Published
2024

8. Development of a set of movable electrostatic probes to characterize the plasma in the ITER neutral beam negative-ion source prototype

Author

Sartori, E., Brombin, M., Laterza, B., Zuin, M., Cavazzana, R., Cervaro, V., Degli Agostini, F., Fadone, M., Fasolo, D., Grando, L., Jain, P., Kisaki, M., Maistrello, A, Moro, G, Pimazzoni, A., Poggi, C., Segalini, B., Shepherd, A., Spolaore, M., Taliercio, C., Tollin, M., Ugoletti, M., Veltri, P., Zamengo, A., and Serianni, G.

Published
2021
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9. On the road to ITER NBIs: SPIDER improvement after first operation and MITICA construction progress

Author

Toigo, V., Marcuzzi, D., Serianni, G., Boldrin, M., Chitarin, G., Bello, S. Dal, Grando, L., Luchetta, A., Pasqualotto, R., Zaccaria, P., Zanotto, L., Agnello, R., Agostinetti, P., Agostini, M., Antoni, V., Aprile, D., Barbisan, M., Battistella, M., Berton, G., Bigi, M., Brombin, M., Candeloro, V., Canton, A., Casagrande, R., Cavallini, C., Cavazzana, R., Cordaro, L., Cruz, N., Palma, M. Dalla, Dan, M., De Lorenzi, A., Delogu, R., De Muri, M., Denizeau, S., Fadone, M., Fellin, F., Ferro, A., Gaio, E., Gasparini, F., Gasparrini, C., Gnesotto, F., Jain, P., Krastev, P., Lopez-Bruna, D., Lorenzini, R., Maistrello, A., Manduchi, G., Manfrin, S., Marconato, N., Martines, E., Martini, G., Martini, S., Milazzo, R., Patton, T., Pavei, M., Peruzzo, S., Pilan, N., Pimazzoni, A., Poggi, C., Pomaro, N., Pouradier-Duteil, B., Recchia, M., Rigoni-Garola, A., Rizzolo, A., Sartori, E., Shepherd, A., Siragusa, M., Sonato, P., Sottocornola, A., Spada, E., Spagnolo, S., Spolaore, M., Taliercio, C., Terranova, D., Tinti, P., Tomsič, P., Trevisan, L., Ugoletti, M., Valente, M., Vignando, M., Zagorski, R., Zamengo, A., Zaniol, B., Zaupa, M., Zuin, M., Cavenago, M., Boilson, D., Rotti, C., Veltri, P., Decamps, H., Dremel, M., Graceffa, J., Geli, F., Urbani, M., Zacks, J., Bonicelli, T., Paolucci, F., Garbuglia, A., Agarici, G., Gomez, G., Gutierrez, D., Kouzmenko, G., Labate, C., Masiello, A., Mico, G., Moreno, J-F, Pilard, V., Rousseau, A., Simon, M., Kashiwagi, M., Tobari, H., Watanabe, K., Maejima, T., Kojima, A., Oshita, E., Yamashita, Y., Konno, S., Singh, M., Chakraborty, A., Patel, H., Singh, N.P., Fantz, U., Bonomo, F., Cristofaro, S., Heinemann, B., Kraus, W., Wimmer, C., Wünderlich, D., Fubiani, G., Tsumori, K., Croci, G., Gorini, G., McCormack, O., Muraro, A., Rebai, M., Tardocchi, M., Giacomelli, L., Rigamonti, D., Taccogna, F., Bruno, D., Rutigliano, M., D'Arienzo, M., Tonti, A., and Panin, F.

Published
2021
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12. An active feedback recovery technique from disruption events induced by m=2 n=1 tearing modes in ohmically heated tokamak plasmas

Author

Zanca, P., Paccagnella, R., Finotti, C., Fassina, A., Manduchi, G., Cavazzana, R., Franz, P., Piron, C., and Piron, L.

Subjects
Physics - Plasma Physics
Abstract

We present experimental results of magnetic feedback control on the m=2, n=1 tearing mode in RFX-mod operated as a circular ohmically heated tokamak. The feedback suppression of the non-resonant m=2, n=1 Resistive Wall Mode (RWM) in q(a)<2 plasmas is a well-established result of RFX-mod. The control of the tearing counterpart, which develops in q(a)>2 equilibrium, is instead a more difficult issue. In fact, the disruption induced by a growing amplitude m=2, n=1 tearing mode can be prevented by feedback only when the resonant surface q=2 is close to the plasma edge, namely 2

Published
2015
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13. Spatiotemporal synchronization of drift waves in a magnetron sputtering plasma

Author

Martines, E., Zuin, M., Cavazzana, R., Adámek, J., Antoni, V., Serianni, G., Spolaore, M., and Vianello, N.

Subjects
Physics - Plasma Physics
Abstract

A feedforward scheme is applied for drift waves control in a magnetized magnetron sputtering plasma. A system of driven electrodes collecting electron current in a limited region of the explored plasma is used to interact with unstable drift waves. Drift waves actually appear as electrostatic modes characterized by discrete wavelengths of the order of few centimeters and frequencies of about 100 kHz. The effect of external quasi-periodic, both in time and space, travelling perturbations is studied. Particular emphasis is given to the role played by the phase relation between the natural and the imposed fluctuations. It is observed that it is possible by means of localized electrodes, collecting currents which are negligible with respect to those flowing in the plasma, to transfer energy to one single mode and to reduce that associated to the others. Due to the weakness of the external action, only partial control has been achieved., Comment: Submitted to Physics of Plasmas

Published
2014
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14. The new vessel complex for the RFX-mod2 experiment: An effective synergy between fusion research and technological development

Author

Peruzzo, S, Aprile, D, Dalla Palma, M, Pavei, M, Rizzetto, D, Rizzolo, A, Abate, D, Agostinetti, P, Agostini, M, Andreani, R, Anselmi, F, Battistin, F, Bernardi, A, Bernardi, M, Berton, G, Bettini, P, Bigi, M, Bonotto, M, Brombin, M, Canton, A, Carraro, L, Cavazzana, R, Cordaro, L, Corniani, G, Dal Bello, S, De Lorenzi, A, De Masi, G, Degli Agostini, F, Franchin, L, Franz, P, Gambetta, G, Gnesotto, F, Grando, L, Innocente, P, Laterza, B, Lotto, L, Manfrin, S, Marchiori, G, Marconato, N, Marcuzzi, D, Marrelli, L, Martines, E, Moresco, M, Novella, A, Piovan, R, Pomaro, N, Rossetto, F, Siragusa, M, Sonato, P, Spagnolo, S, Spolaore, M, Taliercio, C, Terranova, D, Tiso, A, Trevisan, L, Valente, M, Valisa, M, Zaupa, M, Zuin, M, Peruzzo S., Aprile D., Dalla Palma M., Pavei M., Rizzetto D., Rizzolo A., Abate D., Agostinetti P., Agostini M., Andreani R., Anselmi F., Battistin F., Bernardi A., Bernardi M., Berton G., Bettini P., Bigi M. A., Bonotto M., Brombin M., Canton A., Carraro L., Cavazzana R., Cordaro L., Corniani G., Dal Bello S., De Lorenzi A., De Masi G., Degli Agostini F., Franchin L., Franz P., Gambetta G., Gnesotto F., Grando L., Innocente P., Laterza B., Lotto L., Manfrin S., Marchiori G., Marconato N., Marcuzzi D., Marrelli L., Martines E., Moresco M., Novella A., Piovan R., Pomaro N., Rossetto F., Siragusa M., Sonato P., Spagnolo S., Spolaore M., Taliercio C., Terranova D., Tiso A., Trevisan L., Valente M., Valisa M., Zaupa M., Zuin M., Peruzzo, S, Aprile, D, Dalla Palma, M, Pavei, M, Rizzetto, D, Rizzolo, A, Abate, D, Agostinetti, P, Agostini, M, Andreani, R, Anselmi, F, Battistin, F, Bernardi, A, Bernardi, M, Berton, G, Bettini, P, Bigi, M, Bonotto, M, Brombin, M, Canton, A, Carraro, L, Cavazzana, R, Cordaro, L, Corniani, G, Dal Bello, S, De Lorenzi, A, De Masi, G, Degli Agostini, F, Franchin, L, Franz, P, Gambetta, G, Gnesotto, F, Grando, L, Innocente, P, Laterza, B, Lotto, L, Manfrin, S, Marchiori, G, Marconato, N, Marcuzzi, D, Marrelli, L, Martines, E, Moresco, M, Novella, A, Piovan, R, Pomaro, N, Rossetto, F, Siragusa, M, Sonato, P, Spagnolo, S, Spolaore, M, Taliercio, C, Terranova, D, Tiso, A, Trevisan, L, Valente, M, Valisa, M, Zaupa, M, Zuin, M, Peruzzo S., Aprile D., Dalla Palma M., Pavei M., Rizzetto D., Rizzolo A., Abate D., Agostinetti P., Agostini M., Andreani R., Anselmi F., Battistin F., Bernardi A., Bernardi M., Berton G., Bettini P., Bigi M. A., Bonotto M., Brombin M., Canton A., Carraro L., Cavazzana R., Cordaro L., Corniani G., Dal Bello S., De Lorenzi A., De Masi G., Degli Agostini F., Franchin L., Franz P., Gambetta G., Gnesotto F., Grando L., Innocente P., Laterza B., Lotto L., Manfrin S., Marchiori G., Marconato N., Marcuzzi D., Marrelli L., Martines E., Moresco M., Novella A., Piovan R., Pomaro N., Rossetto F., Siragusa M., Sonato P., Spagnolo S., Spolaore M., Taliercio C., Terranova D., Tiso A., Trevisan L., Valente M., Valisa M., Zaupa M., and Zuin M.

Published
2023

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

Author

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

Abstract

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

Published
2023

16. Lessons learned after three years of SPIDER operation and the first MITICA integrated tests

Author

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

Abstract

ITER envisages the use of two heating neutral beam injectors plus an optional one as part of the auxiliary heating and current drive system, to reach the desired performances during its various phases of operation. The 16.5 MW expected neutral beam power per injector is several notches higher than worldwide existing facilities. In order to enable such development, a Neutral Beam Test Facility (NBTF) was established at Consorzio RFX, exploiting the synergy of two test beds, called SPIDER and MITICA. SPIDER is dedicated developing and characterizing large efficient negative ion sources at relevant parameters in ITER-like conditions: source and accelerator located in the same vacuum where the beam propagates, immunity to electromagnetic interferences of multiple radio-frequency (RF) antennas, avoidance of RF-induced discharges on the outside of the source. Three years of experiments on SPIDER have addressed to the necessary design modifications to enable full performances. The source is presently under a long shut-down phase to incorporate learnings from the experimental campaign, in particular events/issues occurred during operation, which led to the identification of improvement opportunities/necessities (e.g. RF discharges, local burns, water leaks, other damages, configuration/design upgrades to maximize chances/margin to quest target parameters). Parallelly, developments on MITICA, the full-scale prototype of the ITER Neutral Beam Injector (NBI) featuring a 1 MV accelerator and ion neutralization, are underway including manufacturing of the beam source, accelerator and the beam line components, while power supplies and auxiliary plants, already installed, are under final testing and commissioning. Integration, commissioning and tests of the 1 MV power supplies are essential for this first-of-kind system, unparalleled both in research and industry field. 1.2 MV dc insulating tests of high voltage components were successfully completed. The integrated test to confir

Published
2023

18. SPIDER in the roadmap of the ITER neutral beams

Author

Serianni, G., Toigo, V., Bigi, M., Boldrin, M., Chitarin, G., Dal Bello, S., Grando, L., Luchetta, A., Marcuzzi, D., Pasqualotto, R., Pomaro, N., Zaccaria, P., Zanotto, L., Agostinetti, P., Agostini, M., Antoni, V., Aprile, D., Barbisan, M., Battistella, M., Brombin, M., Cavazzana, R., Dalla Palma, M., Dan, M., De Lorenzi, A., Delogu, R., De Muri, M., Denizeau, S., Fadone, M., Fellin, F., Ferbel, L., Ferro, A., Gaio, E., Gambetta, G., Gasparini, F., Gnesotto, F., Jain, P., Maistrello, A., Manduchi, G., Manfrin, S., Marchiori, G., Marconato, N., Moresco, M., Patton, T., Pavei, M., Peruzzo, S., Pilan, N., Pimazzoni, A., Piovan, R., Poggi, C., Recchia, M., Rizzolo, A., Rostagni, G., Sartori, E., Siragusa, M., Sonato, P., Spada, E., Spagnolo, S., Spolaore, M., Taliercio, C., Tinti, P., Ugoletti, M., Valente, M., Zamengo, A., Zaniol, B., Zaupa, M., Baltador, C., Cavenago, M., Boilson, D., Rotti, C., Veltri, P., Bonicelli, T., Paolucci, F., Muriel, S., Masiello, A., Chakraborty, A., Patel, H., Singh, N.P., Fantz, U., Heinemann, B., Kraus, W., Kashiwagi, M., and Tsumori, K.

Published
2019
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21. Diagnostics for plasma control – From ITER to DEMO

Author

Biel, W., Albanese, R., Ambrosino, R., Ariola, M., Berkel, M.V., Bolshakova, I., Brunner, K.J., Cavazzana, R., Cecconello, M., Conroy, S., Dinklage, A., Duran, I., Dux, R., Eade, T., Entler, S., Ericsson, G., Fable, E., Farina, D., Figini, L., Finotti, C., Franke, Th., Giacomelli, L., Giannone, L., Gonzalez, W., Hjalmarsson, A., Hron, M., Janky, F., Kallenbach, A., Kogoj, J., König, R., Kudlacek, O., Luis, R., Malaquias, A., Marchuk, O., Marchiori, G., Mattei, M., Maviglia, F., De Masi, G., Mazon, D., Meister, H., Meyer, K., Micheletti, D., Nowak, S., Piron, Ch., Pironti, A., Rispoli, N., Rohde, V., Sergienko, G., El Shawish, S., Siccinio, M., Silva, A., da Silva, F., Sozzi, C., Tardocchi, M., Tokar, M., Treutterer, W., and Zohm, H.

Published
2019
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22. Direct observation of current in type I ELM filaments on Asdex Upgrade

Author

Vianello, N., Naulin, V., Schrittwieser, R., Muller, H. W., Zuin, M., Ionita, C., Rasmussen, J. J., Mehlmann, F., Rohde, V., Cavazzana, R., and Maraschek, M.

Subjects
Physics - Plasma Physics
Abstract

Magnetically confined plasmas are often subject to relaxation oscillations accompanied by large transport events. This is particularly the case for the high confinement regime of tokamaks where these events are termed edge localized modes (ELMs). They result in the temporary breakdown of the high confinement and lead to high power loads on plasma facing components. Present theories of ELM generation rely on a combined effect of edge currents and the edge pressure gradient exceeding critical values which result in intermediate mode number ($n \cong 10-15$) structures (\emph{filaments}) localized in the perpendicular plane and extended along the field line. It is shown here by detailed localized measurements of the three components of the magnetic field perturbation carried by an individual type I ELM filament that these filaments carry a substantial current. The observations provide essential information for the understanding of ELM dynamics., Comment: submitted to Physical Review Letters. New revised version after other comments from another referee. Last revision after other referee Comments

Published
2009

23. Resistive g-modes in a reversed field pinch plasma

Author

Zuin, M., Spagnolo, S., Paccagnella, R., Martines, E., Cavazzana, R., Serianni, G., Spolaore, M., and Vianello, N.

Subjects
Physics - Plasma Physics
Abstract

First direct experimental evidence of high frequency, high toroidal mode number (n>20), magnetic fluctuations due to unstable resistive interchange modes (g-modes) resonant in the edge region of a reversed field pinch (RFP) plasma is presented. Experimental characterization of time and space periodicities of the modes is provided by means of highly resolved in-vessel edge and insertable magnetic diagnostics. It is found that the spectral mode properties are in good agreement with the predictions of the theoretical linear resistive magnetohydrodynamic stability analysis. A simple model is proposed for the observed saturation levels of the modes., Comment: Submitted to Physical Review Letters

Published
2009
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24. Drift-Alfven vortex structures in the edge region of a fusion relevant plasma

Author

Vianello, N., Spolaore, M., Martines, E., Cavazzana, R., Serianni, G., Zuin, M., Spada, E., and Antoni, V.

Subjects
Physics - Plasma Physics
Abstract

Edge turbulent structures are commonly observed in fusion devices and are generally believed to be responsible for confinement degradation. Among their origin Drift-Alfven turbulence is one of the most commonly suggested. Drift-Alfven paradigm allows the existence of localized vortex-like structures observed also in various systems. Here we present the evidence of the presence of drift-Alfv\'en vortices in the edge region of RFX-Mod RFP device, showing how these structures are responsible for electromagnetic turbulence at the edge and its intermittent nature., Comment: 4 pages, 5 figures, Revised version submitted for publication to Physical Review Letters

Published
2009
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25. On the statistics of edge fluctuations: comparative study between various fusion devices

Author

Sattin, F., Agostini, M., Scarin, P., Vianello, N., Cavazzana, R., Marrelli, L., Serianni, G., Zweben, S. J., Maqueda, R. J., Yagi, Y., Sakakita, H., Koguchi, H., Kiyama, S., Hirano, Y., and Terry, J. L.

Subjects
Physics - Plasma Physics
Abstract

In this paper we present a statistical study of edge fluctuations taken with the Gas Puffing Imaging (GPI) diagnostics. We carry out a comparison of GPI signal from an extensive database including four devices (two Tokamaks and two Reversed Field Pinches). The data are analyzed in terms of their statistical moments Skewness and Kurtosis, as done in [B. Labit, et al, Phys. Rev. Lett. \textbf{98}, 255002 (2007)]. The data align along parabolic curves, although different from machine to machine, with some spread around the best-fitting curve. A discussion about the meaning of the parabolic trend as well as the departure of real data from it is provided. A phenomenological model is finally provided, attempting to accomodate experimental evidence., Comment: To appear in Plasma Physics and Controlled Fusion

Published
2009
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26. About the parabolic relation existing between the skewness and the kurtosis in time series of experimental data

Author

Sattin, F., Agostini, M., Cavazzana, R., Serianni, G., Scarin, P., and Vianello, N.

Subjects
Physics - Data Analysis, Statistics and Probability
Abstract

In this work we investigate the origin of the parabolic relation between skewness and kurtosis often encountered in the analysis of experimental time-series. We argue that the numerical values of the coefficients of the curve may provide informations about the specific physics of the system studied, whereas the analytical curve per se is a fairly general consequence of a few constraints expected to hold for most systems., Comment: To appear in Physica Scripta

Published
2009
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27. Statistical features of edge turbulence in RFX-mod from Gas Puffing Imaging

Author

Sattin, F., Scarin, P., Agostini, M., Cavazzana, R., Serianni, G., Spolaore, M., and Vianello, N.

Subjects
Physics - Plasma Physics
Abstract

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

Published
2006
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29. To what extent can dynamical models describe statistical features of turbulent flows?

Author

Carbone, V., Cavazzana, R., Antoni, V., Sorriso-Valvo, L., Spada, E., Regnoli, G., Giuliani, P., Vianello, N., Lepreti, F., Bruno, R., Martines, E., and Veltri, P.

Subjects
Nonlinear Sciences - Chaotic Dynamics, Nonlinear Sciences - Adaptation and Self-Organizing Systems
Abstract

Statistical features of "bursty" behaviour in charged and neutral fluid turbulence, are compared to statistics of intermittent events in a GOY shell model, and avalanches in different models of Self Organized Criticality (SOC). It is found that inter-burst times show a power law distribution for turbulent samples and for the shell model, a property which is shared only in a particular case of the running sandpile model. The breakdown of self-similarity generated by isolated events observed in the turbulent samples, is well reproduced by the shell model, while it is absent in all SOC models considered. On this base, we conclude that SOC models are not adequate to mimic fluid turbulence, while the GOY shell model constitutes a better candidate to describe the gross features of turbulence., Comment: 14 pages, 4 figures, in press on Europhys. Lett. (may 2002)

Published
2002
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31. Lessons learned after three years of SPIDER operation and the first MITICA integrated tests

Author

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

Published
2023
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34. Diagnostics, data acquisition and control of the divertor test tokamak experiment

Author

Albanese, R., Ambrosino, R., Ariola, M., De Tommasi, G., Pironti, A., Cavinato, M., Neto, A., Piccolo, F., Sartori, F., Ranz, R., Carraro, L., Canton, A., Cavazzana, R., Fassina, A., Franz, P., Innocente, P., Luchetta, A., Manduchi, G., Marrelli, L., Martines, E., Peruzzo, S., Puiatti, M.E., Scarin, P., Spizzo, G., Spolaore, M., Valisa, M., Gorini, G., Nocente, M., Sozzi, C., Apicella, M.L., Gabellieri, L., Maddaluno, G., and Ramogida, G.

Published
2017
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35. Physics of tearing mode rotation and slow-down in the RFX-mod tokamak

Author

Cordaro, L, Zanca, P, Zuin, M, Auriemma, F, Fassina, A, Martines, E, Zaniol, B, Cavazzana, R, De Masi, G, Grenfell, G, Momo, B, Spagnolo, S, Spolaore, M, Vianello, N, Cordaro L., Zanca P., Zuin M., Auriemma F., Fassina A., Martines E., Zaniol B., Cavazzana R., De Masi G., Grenfell G., Momo B., Spagnolo S., Spolaore M., Vianello N., Cordaro, L, Zanca, P, Zuin, M, Auriemma, F, Fassina, A, Martines, E, Zaniol, B, Cavazzana, R, De Masi, G, Grenfell, G, Momo, B, Spagnolo, S, Spolaore, M, Vianello, N, Cordaro L., Zanca P., Zuin M., Auriemma F., Fassina A., Martines E., Zaniol B., Cavazzana R., De Masi G., Grenfell G., Momo B., Spagnolo S., Spolaore M., and Vianello N.

Abstract

We present a study of the fast, spontaneous rotation regime of tearing modes (TM) in the RFX-mod circular tokamak discharges. Integrated analyses of magnetic, flow and kinetic measurements, are discussed. This analysis of rotation frequency components related to the ion flow and diamagnetic drift shows that the TM fast rotation is mainly driven by the diamagnetic drift. The global decrease of the temperature profile, induced by a growing mode amplitude, can explain the slowing-down of the rotation, which in turn can trigger a potentially disruptive sequence. We show that in RFX-mod the slowing-down cannot be explained solely on the basis of the electromagnetic torque with the external conductive structures, as often reported in literature from other experiments. This analysis, indeed, suggests a strong relationship between the TM dynamics and the transport physics. Statistical analysis of disruptions with slowing down of island rotation shows that TMs take a part in the disruption, even without a locking to the wall.

Published
2022

36. Dynamics of ultralow- q plasmas in the RFX-mod device

Author

Zuin, M, Agostini, M, Auriemma, F, Bonfiglio, D, Cappello, S, Carraro, L, Cavazzana, R, Cordaro, L, Franz, P, Marrelli, L, Martines, E, Puiatti, M, Piovan, R, Spizzo, G, Terranova, D, Vianello, N, Zanca, P, Zaniol, B, Zanotto, L, Zuin M., Agostini M., Auriemma F., Bonfiglio D., Cappello S., Carraro L., Cavazzana R., Cordaro L., Franz P., Marrelli L., Martines E., Puiatti M. E., Piovan R., Spizzo G., Terranova D., Vianello N., Zanca P., Zaniol B., Zanotto L., Zuin, M, Agostini, M, Auriemma, F, Bonfiglio, D, Cappello, S, Carraro, L, Cavazzana, R, Cordaro, L, Franz, P, Marrelli, L, Martines, E, Puiatti, M, Piovan, R, Spizzo, G, Terranova, D, Vianello, N, Zanca, P, Zaniol, B, Zanotto, L, Zuin M., Agostini M., Auriemma F., Bonfiglio D., Cappello S., Carraro L., Cavazzana R., Cordaro L., Franz P., Marrelli L., Martines E., Puiatti M. E., Piovan R., Spizzo G., Terranova D., Vianello N., Zanca P., Zaniol B., and Zanotto L.

Abstract

The results are presented of an experimental activity performed in the RFX-mod device aimed at characterizing plasma dynamics in the so-called Ultralow-q (ULq) magnetic configuration, which corresponds to edge safety factor values below 1. The role of the edge safety factor in determining plasma dynamics is studied. In particular, a characterization of MHD activity is performed. The results of dedicated non-linear 3D visco-resistive MHD simulations are in good quantitative agreement with the experimental observations. In particular, the predicted tendency for ULq plasmas to be characterized by magnetic spectra dominated by a single mode (either a kink or a double resonant internal mode) is confirmed by experiment. Magnetic reconnection plays a relevant role in determining the dynamics of the magnetic topology. Both almost quiescent and largely fluctuating plasmas are observed with a strong sensitivity on the edge safety factor. The main MHD properties of the ULq are compared to those of RFP and tokamak discharges, also produced in the RFX-mod device. MHD modes exhibit toroidal rotation at a frequency depending on mode amplitude. Differently from what encountered in RFP plasmas at comparable current levels, no wall locking is detected.

Published
2022

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

Author

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

Published
2023
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43. Physics of tearing mode rotation and slow-down in the RFX-mod tokamak

Author

Cordaro, L., primary, Zanca, P., additional, Zuin, M., additional, Auriemma, F., additional, Fassina, A., additional, Martines, E., additional, Zaniol, B., additional, Cavazzana, R., additional, De Masi, G., additional, Grenfell, G., additional, Momo, B., additional, Spagnolo, S., additional, Spolaore, M., additional, and Vianello, N., additional

Published
2022
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44. The helical resonator: A scheme for radio frequency plasma generation

Author

Martines, E, Cavazzana, R, Cordaro, L, Zuin, M, Martines E., Cavazzana R., Cordaro L., Zuin M., Martines, E, Cavazzana, R, Cordaro, L, Zuin, M, Martines E., Cavazzana R., Cordaro L., and Zuin M.

Abstract

The helical resonator is a scheme for the production of high voltage at radio frequency, useful for gas breakdown and plasma sustainment, which, through a proper design, enables avoiding the use of a matching network. In this work, we consider the treatment of the helical resonator, including a grounded shield, as a transmission line with a shorted end and an open one, the latter possibly connected to a capacitive load. The input voltage is applied to a tap point located near the shorted end. After deriving an expression for the velocity factor of the perturbations propagating along the line, and in the special case of the shield at infinity also of the characteristic impedance, we calculate the input impedance and the voltage amplification factor of the resonator as a function of the wave number. Focusing on the resonance condition, which maximizes the voltage amplification, we then discuss the effect of the tap point position, dissipation and the optional capacitive load, in terms of resonator performance and matching to the power supply.

Published
2021

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

Author

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

Abstract

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

Published
2021

46. First operations with caesium of the negative ion source SPIDER

Author

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

Published
2022
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48. Turbulent filament properties in L and H-mode regime in the RFX-mod operating as a tokamak

Author

Grenfell, G, Spolaore, M, Abate, D, Carraro, L, Marrelli, L, Predebon, I, Spagnolo, S, Veranda, M, Agostini, M, van Milligen, B, Cavazzana, R, Cordaro, L, De Masi, G, Franz, P, Hidalgo, C, Martines, E, Momo, B, Puiatti, M, Scarin, P, Vianello, N, Zaniol, B, Zuin, M, Grenfell G, Spolaore M, Abate D, Carraro L, Marrelli L, Predebon I, Spagnolo S, Veranda M, Agostini M, van Milligen BP, Cavazzana R, Cordaro L, De Masi G, Franz P, Hidalgo C, Martines E, Momo B, Puiatti ME, Scarin P, Vianello N, Zaniol B, Zuin M, Grenfell, G, Spolaore, M, Abate, D, Carraro, L, Marrelli, L, Predebon, I, Spagnolo, S, Veranda, M, Agostini, M, van Milligen, B, Cavazzana, R, Cordaro, L, De Masi, G, Franz, P, Hidalgo, C, Martines, E, Momo, B, Puiatti, M, Scarin, P, Vianello, N, Zaniol, B, Zuin, M, Grenfell G, Spolaore M, Abate D, Carraro L, Marrelli L, Predebon I, Spagnolo S, Veranda M, Agostini M, van Milligen BP, Cavazzana R, Cordaro L, De Masi G, Franz P, Hidalgo C, Martines E, Momo B, Puiatti ME, Scarin P, Vianello N, Zaniol B, and Zuin M

Abstract

The dynamics of turbulent filaments in L and ELM-free H-mode in the RFX-mod device operating as a tokamak is discussed in the present work. L-H transition and sustained H-mode have been achieved in the RFX-mod with the aid of an external electrode biasing (Spolaoreet al 2017 Nucl. Fusion57116039). Through advanced statistical techniques, turbulent filaments are detected and tracked from the edge to the scrape-off layer (SOL) in a two-dimension floating potential map (measured with a 2D array of Langmuir probes) related with extreme events of a fixed ion saturation current signal in the SOL. While in L-mode filaments travel almost freely, their motion becomes restricted to the near SOL during the induced biasing H-mode. In this region, the background shear decorrelation time becomes shorter than the convective filament time, favouring its suppression. However, the experimental observation of a nearly 'trapped' monopole potential points out the possible role of the vortex selection mechanism. The sign and magnitude of the turbulent parallel vorticity are consistent with theE x Bbackground vorticity in the SOL in this regime, while in L-mode, the inferred turbulent vorticity is always above the background one. The sparse filamentary transport in the far SOL during H-mode is further confirmed from the measurements of a poloidally symmetric array of electrostatic sensors on the wall. Lastly, the radial velocity of filaments in both regimes was discussed in the framework of analytical scalings. Filaments in L-mode exhibit a reasonable agreement with the sheath-limited regime in the cold ion approximation, with a non-negligible associated parallel current density measured with a set of 3-axial pick-up coils installed in the probe head. In H-mode, the collisionality increases near the separatrix while filaments seem to follow the inertial regime before become trapped.

Published
2020

49. The phenomenology of reconnection events in the reversed field pinch

Author

Momo, B, Isliker, H, Cavazzana, R, Zuin, M, Cordaro, L, Lopez-Bruna, D, Martines, E, Predebon, I, Rea, C, Spolaore, M, Vlahos, L, Zanca, P, Momo B, Isliker H, Cavazzana R, Zuin M, Cordaro L, Lopez-Bruna D, Martines E, Predebon I, Rea C, Spolaore M, Vlahos L, Zanca P, Momo, B, Isliker, H, Cavazzana, R, Zuin, M, Cordaro, L, Lopez-Bruna, D, Martines, E, Predebon, I, Rea, C, Spolaore, M, Vlahos, L, Zanca, P, Momo B, Isliker H, Cavazzana R, Zuin M, Cordaro L, Lopez-Bruna D, Martines E, Predebon I, Rea C, Spolaore M, Vlahos L, and Zanca P

Abstract

The phenomenology of reconnection events, associated to relaxations in high-current (similar to 1.5 MA) plasmas of the reversed-field pinch device RFX-mod, is shown. Each relaxation event can be described as a series of stages starting in the core and propagating towards the plasma edge. In an initial stage (trigger), the evolution of the q profile brings resonant layers closer together, allowing for an interaction of the current sheets associated to tearing modes at the respective rational values of q. The phase locking of the resonant modes then initiates the reconnection process that, once started, changes the magnetic topology bringing the initially helical state to a more chaotic configuration.

Published
2020

50. Wound healing improvement in large animals using an indirect helium plasma treatment

Author

Martines, E, Brun, P, Cavazzana, R, Cordaro, L, Zuin, M, Martinello, T, Gomiero, C, Perazzi, A, Melotti, L, Maccatrozzo, L, Patruno, M, Iacopetti, I, Martines E., Brun P., Cavazzana R., Cordaro L., Zuin M., Martinello T., Gomiero C., Perazzi A., Melotti L., Maccatrozzo L., Patruno M., Iacopetti I., Martines, E, Brun, P, Cavazzana, R, Cordaro, L, Zuin, M, Martinello, T, Gomiero, C, Perazzi, A, Melotti, L, Maccatrozzo, L, Patruno, M, Iacopetti, I, Martines E., Brun P., Cavazzana R., Cordaro L., Zuin M., Martinello T., Gomiero C., Perazzi A., Melotti L., Maccatrozzo L., Patruno M., and Iacopetti I.

Abstract

Background: To optimize wound healing, the use of low-temperature atmospheric pressure plasma (ionized gas) has been proposed as an innovative therapeutic method for treating extensive and chronic wound. The aim of this study was to evaluate the specific effects of an indirect helium plasma treatment in a sheep surgical wound model based on clinical, histopathological and molecular analyses. This study was part of a larger study aimed at assessing five different wound healing improvement methods. Methods: Six sheep were used in this study. Six square wounds were performed on the back of each sheep. Five of the lesions were used to analyze the effect of five different treatments, one of which was the plasma treatment. The sixth lesions was used as control. A 2-min plasma treatment was daily performed, using a radiofrequency helium plasma source for indirect treatments, until complete wound healing was obtained. Biopsies were performed at two and six weeks. The plasma effects were tested through clinical evaluation, histopathological and immunohistological evaluation, real time PCR analysis, bacteriological evaluation and intracellular ROS evaluation. Results: Wound closure time for the plasma-treated wounds was quicker than that of the control group. Plasma treatment drastically reduced the bacterial load in the wounds. A strong increase in intracellular ROS was observed. After six weeks, the inflammatory process was significantly reduced in the plasma-treated case with respect to the control. The plasma treatment was found to lead to an anticipated induction of blood vessel formation, as detected through mRNA expression of VEGF. The high Ki67-positivity at two weeks indicated a strong stimulation of cell proliferation induced by the plasma treatment. The expression of the hair keratine (hKER) at six weeks indicated that the plasma was promoting hair regrowth. The plasma treatment induced an increased rate of reformation of cutaneous adnexa at six weeks. Conclusions

Published
2020

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