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1. Conceptual design of a modular EC heating system for EU-DEMO.

Author

Bruschi, Alessandro, Hogge, Jean-Philippe, Jelonnek, John, Strauss, Dirk, Wu, Chuanren, Aiello, Gaetano, Avramidis, Kostas, Baiocchi, Benedetta, Birlan, Daniel, Chavan, René, Chelis, Ioannis, Clement, Arnaud, Collaku, Aldo, Crisinel, Fabien, Difonzo, Rosa, Ell, Benjamin, Fanale, Francesco, Fanelli, Pierluigi, Figini, Lorenzo, and Gajetti, Eleonora

Subjects
CONCEPTUAL design, MODULAR design, TOKAMAKS, CIRCULAR waveguides, FUSION reactors, FUSION reactor blankets, HEATING, PLASMA heating
Abstract

The European DEMO (EU-DEMO) reactor studies within EUROfusion aim to develop a fusion power plant concept. The large tokamak device needs an auxiliary heating power which, at the present stage, is provided by the Electron Cyclotron (EC) heating system with up to 130 MW foreseen to reach different regions of plasma for heating, suppression of instabilities and the possibility to support ramp-up and ramp-down phases. The present conceptual design of the system is based on 2 MW coaxial-cavity gyrotron sources, a transmission line (TL) using both circular corrugated waveguides and quasi-optical evacuated multi-beam TLs, and mirror antennas located in the Equatorial Port. In order to create a modular system, the sources are grouped in 'clusters', whose powers are combined in the quasi-optical TL, up to the tokamak building, where they are split and routed as single waveguides. In the launcher, they are combined together again on the launching mirrors, to save space for the apertures in the Breeding Blanket. The present EC heating system has a certain flexibility to adapt to changing design guidelines. The development status of the system is presented. [ABSTRACT FROM AUTHOR]

Published
2024
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2. EU DEMO EC equatorial launcher pre-conceptual performance studies

Author

Garavaglia, Saul, Baiocchi, Benedetta, Bruschi, Alessandro, Čufar, Aljaž, Fanale, Francesco, Granucci, Gustavo, Moro, Alessandro, Poli, Emanuele, Rispoli, Natale, Scherer, Theo, Siccinio, Mattia, Späh, Peter, Strauß, Dirk, Tigelis, Ioannis, Tsironis, Christos, Franke, Thomas, and Tran, Minh Quang

Published
2020
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3. ECH and ECCD modelling studies for DTT

Author

Baiocchi Benedetta, Figini Lorenzo, Bruschi Alessandro, Fanale Francesco, Garavaglia Saul, Granucci Gustavo, and Romano Afra

Subjects
Physics, QC1-999
Abstract

In this work the Electron Cyclotron (EC) physics performances of the EC system foreseen for the new Divertor Tokamak Test facility (DTT) are investigated using the beam tracing code GRAY on the flat top phase of the most recent DTT full power scenario. The whole core plasma region can be reached by EC beams with complete absorption, assuring bulk heating and core current drive (CD) for profile tailoring, and NTM mitigation in correspondence of the rational surfaces. A detailed analysis regarding modifications of the EC propagation, absorption and CD location due to density fluctuations caused by pellet injection is performed. The compatibility between the EC system and the pellet injection system is verified: the density variations due to pellet injection are foreseen to negligibly influence the EC performances, allowing the EC beams to reach the plasma central region for bulk heating and to drive current on the rational surfaces for NTM mitigation. Finally, the polarization variations originated by the angle steering foreseen for the operational and physics tasks accomplishment during the flat top phase of the discharge are assessed. Negligible power losses have been found keeping fixed polarization during the needed steering.

Published
2023
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4. The tunable resonant IC antenna concept and its design for DTT experiment

Author

Milanesio, Daniele, primary, Galindo Huertas, David Leonardo, additional, Ceccuzzi, Silvio, additional, Vecchi, Giuseppe, additional, Baiocchi, Benedetta, additional, Cardinali, Alessandro, additional, Mascali, David, additional, Mauro, Giorgio Sebastiano, additional, Mirizzi, Francesco, additional, Pidatella, Angelo, additional, Ravera, Gian Luca, additional, Torrisi, Giuseppe, additional, and Tuccillo, Angelo A, additional

Published
2023
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5. Core integrated simulations for the Divertor Tokamak Test facility scenarios towards consistent core–pedestal–SOL modelling

Author

Casiraghi, Irene, primary, Mantica, Paola, additional, Ambrosino, Roberto, additional, Aucone, Lorenzo, additional, Baiocchi, Benedetta, additional, Balbinot, L., additional, Barberis, Tommaso, additional, Castaldo, A., additional, Cavedon, Marco, additional, Frassinetti, Lorenzo, additional, Innocente, Paolo, additional, Koechl, Florian, additional, Nowak, Silvana, additional, Agostinetti, Piero, additional, Ceccuzzi, Silvio, additional, Figini, Lorenzo, additional, Granucci, Gustavo, additional, and Vincenzi, Pietro, additional

Published
2023
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6. Side emissions during EC injection for PDI studies in FTU tokamak

Author

Bruschi Alessandro, Alessi Edoardo, Baiocchi Benedetta, Bin William, D’Arcangelo Ocleto, Fanale Francesco, Figini Lorenzo, Galperti Cristian, Garavaglia Saul, Gittini Giuseppe, Granucci Gustavo, Grosso Giovanni, Lubyako Lev, Mazzotta Cristina, Mellera Vittoria, Moro Alessandro, Orsitto Francesco, Pallotta Fabrizio, Rocchi Giuliano, Simonetto Alessandro, Tartari Umberto, and Tudisco Onofrio

Subjects
Physics, QC1-999
Abstract

The evidence of Parametric Decay Instabilities (PDI) excited by the ECH power injected in O-Mode has been explored in FTU Tokamak, using the Collective Thomson Scattering (CTS) diagnostic. The experiments show evidences to support the hypothesis of low-threshold excitation of waves generated by PDI mechanisms, formerly proposed in the case of 2nd harmonic X-mode injection in TEXTOR and ASDEX-U. Theoretical analysis predicts low-threshold parametric decay also for O-mode pump-wave injection, which can be injected in FTU at frequencies close to the first Harmonic EC resonance. Experiments were made at different magnetic fields, injecting the 140 GHz probe and observing the emission from the second antenna of the EC launcher in poloidally symmetric and asymmetric configurations, in presence of MHD islands. The signal is detected by the CTS radiometers, with a fast digitizer allowing the spectral reconstruction at very fine time and frequency scales. Different types of emissions are studied in detail, comparing them with the magnetic island rotation frequency in different plasma conditions. In order to locate the plasma volume originating the emissions, a new antenna and receiving line has been installed.

Published
2019
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7. Theory based simulations to predict the plasma profiles of the Divertor Tokamak Test facility baseline scenarios

Author

Casiraghi, I, Mantica, P, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Balestri, A, Barberis, T, Bonanomi, N, Castaldo, A, Frassinetti, L, Innocente, P, Koechl, F, Mariani, A, Nowak, S, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Casiraghi Irene, Mantica Paola, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Balestri Alessandro, Barberis Tommaso, Bonanomi Nicola, Castaldo Antonio, Frassinetti Lorenzo, Innocente Paolo, Koechl Florian, Mariani Alberto, Nowak Silvana, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Casiraghi, I, Mantica, P, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Balestri, A, Barberis, T, Bonanomi, N, Castaldo, A, Frassinetti, L, Innocente, P, Koechl, F, Mariani, A, Nowak, S, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Casiraghi Irene, Mantica Paola, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Balestri Alessandro, Barberis Tommaso, Bonanomi Nicola, Castaldo Antonio, Frassinetti Lorenzo, Innocente Paolo, Koechl Florian, Mariani Alberto, Nowak Silvana, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, and Granucci Gustavo

Published
2022

8. Scenario modelling for the Divertor Tokamak Test facility

Author

Casiraghi, I, Mantica, P, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Koechl, F, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Valisa, M, Casiraghi Irene, Mantica Paola, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Koechl Florian, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Valisa Marco, Casiraghi, I, Mantica, P, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Koechl, F, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Valisa, M, Casiraghi Irene, Mantica Paola, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Koechl Florian, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, and Valisa Marco

Abstract

The scenario integrated modelling is a top priority work during the design of a new tokamak, as the Divertor Tokamak Test facility (DTT) under construction at the ENEA Research Center in Frascati. The first simulations of the main baseline scenarios contributed to the optimization of the DTT project, particularly with regard to the machine size and heating systems, besides serving as reference for diagnostics design. In this paper we report the first simulations of the full power baseline scenario in the final configuration of the machine and heating mix.

Published
2022

9. Theory based simulations to predict the plasma profiles of the Divertor Tokamak Test facility baseline scenarios

Author

Casiraghi Irene, Mantica Paola, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Balestri Alessandro, Barberis Tommaso, Bonanomi Nicola, Castaldo Antonio, Frassinetti Lorenzo, Innocente Paolo, Koechl Florian, Mariani Alberto, Nowak Silvana, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Casiraghi, I, Mantica, P, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Balestri, A, Barberis, T, Bonanomi, N, Castaldo, A, Frassinetti, L, Innocente, P, Koechl, F, Mariani, A, Nowak, S, Agostinetti, P, Ceccuzzi, S, Figini, L, and Granucci, G

Subjects
Divertor Tokamak Test facility, DTT, integrated modelling, theory based simulations, transport models, plasma scenarios
Published
2022

10. First-principle integrated modelling of the main scenarios of the new Divertor Tokamak Test facility

Author

Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Nyström Hampus, Valisa Marco, Vincenzi Pietro, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Nyström, H, Valisa, M, and Vincenzi, P

Subjects
Divertor Tokamak Test facility, DTT, integrated modelling, plasma, quasi-linear transport models, Divertor Tokamak Test Facility, DTT
Abstract

In the European Roadmap towards thermonuclear fusion power production, studying the controlled exhaust of energy and particles from a fusion reactor is a top priority research item. This is the main goal of the Divertor Tokamak Test (DTT) facility, a D-shaped superconducting tokamak (R = 2.19 m, a = 0.70 m, BT

Published
2021

11. The new Divertor Tokamak Test facility: main scenario integrated modelling

Author

Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, and Mariani, A

Subjects
Divertor Tokamak Test facility, DTT, integrated modelling, quasi-linear transport models
Published
2021

12. First-principle integrated modelling of the main scenarios of the new Divertor Tokamak Test facility

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Nyström, H, Valisa, M, Vincenzi, P, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Nyström Hampus, Valisa Marco, Vincenzi Pietro, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Nyström, H, Valisa, M, Vincenzi, P, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Nyström Hampus, Valisa Marco, and Vincenzi Pietro

Published
2021

13. Integrated modelling of the main Divertor Tokamak Test facility scenarios

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Dicorato, M, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Innocente, P, Johnson, T, Nyström, H, Valisa, M, Mantica, Paola, Koechl, Florian, Ambrosino, Roberto, Aucone, Lorenzo, Baiocchi, Benedetta, Balbinot, Luca, Castaldo, Antonio, Citrin Jonathan, Dicorato, Mattia, Frassinetti, Lorenzo, Mariani, Alberto, Vincenzi, Pietro, Agostinetti, Piero, Ceccuzzi, Silvio, Figini, Lorenzo, Granucci, Gustavo, Innocente, Paolo, Johnson, Thomas, Nyström, Hampus, Valisa, Marco, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Dicorato, M, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Innocente, P, Johnson, T, Nyström, H, Valisa, M, Mantica, Paola, Koechl, Florian, Ambrosino, Roberto, Aucone, Lorenzo, Baiocchi, Benedetta, Balbinot, Luca, Castaldo, Antonio, Citrin Jonathan, Dicorato, Mattia, Frassinetti, Lorenzo, Mariani, Alberto, Vincenzi, Pietro, Agostinetti, Piero, Ceccuzzi, Silvio, Figini, Lorenzo, Granucci, Gustavo, Innocente, Paolo, Johnson, Thomas, Nyström, Hampus, and Valisa, Marco

Published
2021

14. Overview on the first-principle integrated modelling of the main scenarios of the new Divertor Tokamak Test facility

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Nyström, H, Valisa, M, Vincenzi, P, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Nyström Hampus, Valisa Marco, Vincenzi Pietro, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Nyström, H, Valisa, M, Vincenzi, P, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Nyström Hampus, Valisa Marco, and Vincenzi Pietro

Published
2021

15. The new Divertor Tokamak Test facility: main scenario integrated modelling

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, Mariani Alberto, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Aucone, L, Baiocchi, B, Balbinot, L, Castaldo, A, Citrin, J, Frassinetti, L, Innocente, P, Mariani, A, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Aucone Lorenzo, Baiocchi Benedetta, Balbinot Luca, Castaldo Antonio, Citrin Jonathan, Frassinetti Lorenzo, Innocente Paolo, and Mariani Alberto

Published
2021

16. First-principle based multi-channel integrated modelling in support to the design of the Divertor Tokamak Test facility

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Baiocchi, B, Castaldo, A, Citrin, J, Dicorato, M, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Aucone, L, Balbinot, L, Ceccuzzi, S, Figini, L, Granucci, G, Innocente, P, Johnson, T, Nyström, H, Valisa, M, Casiraghi, Irene, Mantica, Paola, Koechl, Florian, Ambrosino, Roberto, Baiocchi, Benedetta, Castaldo, Antonio, Citrin, Jonathan, Dicorato, Mattia, Frassinetti, Lorenzo, Mariani, Alberto, Vincenzi, Pietro, Agostinetti, Piero, Aucone, Lorenzo, Balbinot, Luca, Ceccuzzi, Silvio, Figini, Lorenzo, Granucci, Gustavo, Innocente, Paolo, Johnson, Thomas J, Nyström, Hampus, Valisa, Marco, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Baiocchi, B, Castaldo, A, Citrin, J, Dicorato, M, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Aucone, L, Balbinot, L, Ceccuzzi, S, Figini, L, Granucci, G, Innocente, P, Johnson, T, Nyström, H, Valisa, M, Casiraghi, Irene, Mantica, Paola, Koechl, Florian, Ambrosino, Roberto, Baiocchi, Benedetta, Castaldo, Antonio, Citrin, Jonathan, Dicorato, Mattia, Frassinetti, Lorenzo, Mariani, Alberto, Vincenzi, Pietro, Agostinetti, Piero, Aucone, Lorenzo, Balbinot, Luca, Ceccuzzi, Silvio, Figini, Lorenzo, Granucci, Gustavo, Innocente, Paolo, Johnson, Thomas J, Nyström, Hampus, and Valisa, Marco

Abstract

An intensive integrated modelling work of the main scenarios of the new Divertor Tokamak Test (DTT) facility with a single null divertor configuration has been performed using first principle quasi-linear transport models, in support of the design of the device and of the definition of its scientific work programme. First results of this integrated modelling work on DTT (R0 = 2.14 m, a = 0.65 m) are presented here along with outcome of the gyrokinetic simulations used to validate the reduced models in the DTT range of parameters. As a result of this work, the heating mix has been defined, the size of device has been increased to R0 = 2.19 m and a = 0.70 m, the use of pellets for fuelling has been recommended and reference profiles for diagnostic design, estimates of neutron yields and fast particle losses have been made available.

Published
2021

17. First principle scenario modelling of the Divertor Tokamak Test facility

Author

Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Baiocchi Benedetta, Citrin Jonathan, Frassinetti Lorenzo, Mariani Alberto, Vincenzi Pietro, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Martin Piero, Valisa Marco, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Baiocchi, B, Citrin, J, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Martin, P, and Valisa, M

Subjects
Divertor Tokamak Test facility, DTT, First principle scenario modelling, integrated modelling, quasi-linear transport models, Divertor Tokamak Test facility, DTT, scenario modelling, integrated modelling, quasi-linear transport models
Published
2020

18. First principle scenario modelling of the Divertor Tokamak Test facility

Author

Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Baiocchi, B, Citrin, J, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Martin, P, Valisa, M, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Baiocchi Benedetta, Citrin Jonathan, Frassinetti Lorenzo, Mariani Alberto, Vincenzi Pietro, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Martin Piero, Valisa Marco, Casiraghi, I, Mantica, P, Koechl, F, Ambrosino, R, Baiocchi, B, Citrin, J, Frassinetti, L, Mariani, A, Vincenzi, P, Agostinetti, P, Ceccuzzi, S, Figini, L, Granucci, G, Johnson, T, Martin, P, Valisa, M, Casiraghi Irene, Mantica Paola, Koechl Florian, Ambrosino Roberto, Baiocchi Benedetta, Citrin Jonathan, Frassinetti Lorenzo, Mariani Alberto, Vincenzi Pietro, Agostinetti Piero, Ceccuzzi Silvio, Figini Lorenzo, Granucci Gustavo, Johnson Thomas, Martin Piero, and Valisa Marco

Published
2020

19. Side emissions during EC injection for PDI studies in FTU tokamak.

Author

Poli, E., Laqua, H., Oosterbeek, J., Bruschi, Alessandro, Alessi, Edoardo, Baiocchi, Benedetta, Bin, William, D'Arcangelo, Ocleto, Fanale, Francesco, Figini, Lorenzo, Galperti, Cristian, Garavaglia, Saul, Gittini, Giuseppe, Granucci, Gustavo, Grosso, Giovanni, Lubyako, Lev, Mazzotta, Cristina, Mellera, Vittoria, Moro, Alessandro, and Orsitto, Francesco

Subjects
PARAMETRIC instability, THOMSON scattering, HARMONIC motion, BLOOD volume, FOURIER transforms
Abstract

The evidence of Parametric Decay Instabilities (PDI) excited by the ECH power injected in O-Mode has been explored in FTU Tokamak, using the Collective Thomson Scattering (CTS) diagnostic. The experiments show evidences to support the hypothesis of low-threshold excitation of waves generated by PDI mechanisms, formerly proposed in the case of 2nd harmonic X-mode injection in TEXTOR and ASDEX-U. Theoretical analysis predicts low-threshold parametric decay also for O-mode pump-wave injection, which can be injected in FTU at frequencies close to the first Harmonic EC resonance. Experiments were made at different magnetic fields, injecting the 140 GHz probe and observing the emission from the second antenna of the EC launcher in poloidally symmetric and asymmetric configurations, in presence of MHD islands. The signal is detected by the CTS radiometers, with a fast digitizer allowing the spectral reconstruction at very fine time and frequency scales. Different types of emissions are studied in detail, comparing them with the magnetic island rotation frequency in different plasma conditions. In order to locate the plasma volume originating the emissions, a new antenna and receiving line has been installed. [ABSTRACT FROM AUTHOR]

Published
2019
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20. UNDERSTANDING AND PREDICTING ION HEAT TRANSPORT IN TOKAMAKS

Author

BAIOCCHI, BENEDETTA

Abstract

One of the most attractive options to satisfy the continuously growing world energy demand is controlled thermonuclear fusion. The scientific and technological work for achieving it has been significantly boosted after the recent decision to build the international tokamak ITER (International Thermonuclear Experimental Reactor). Amongst the physical problems still open, understanding and controlling heat transport is of primary importance for the optimization of the operational scenarios of ITER. Given the complexity of plasma transport processes, a full theoretical understanding of the experimental observations and validated numerical models for the simulation of a complete tokamak discharge are not yet available. Work in this field is therefore actively ongoing, with a view to increasing integration between theoretical developments, experimental results and numerical predictions. This is the context in which the present thesis work takes place. It has long been known that the high measured levels of heat transport in tokamaks are due to turbulent phenomena, in particular the so-called drift waves. The ion heat transport, on which is focused this thesis, is carried by ion temperature gradient (ITG) modes, that are destabilized when a threshold value of the inverse ion temperature gradient length (1/LTi=|?Ti/Ti|) is exceeded. Above threshold, the ion heat flux is a strongly increasing function of 1/LTi, which prevents the Ti profiles from departing significantly from threshold, a property known as profile stiffness. The main target of ion heat transport studies is to find ways to suppress or mitigate ITG modes, namely by increasing the threshold or reducing the stiffness level, in order to be able to achieve high core Ti values without having to rely on too high edge Ti values, which would raise plasma-wall interaction issues. Sophisticated ion heat transport experiments carried out at the JET tokamak have recently indicated that a strong reduction of ion stiffness takes place in presence of low magnetic shear and high toroidal rotation. This mechanism has been proposed as the key ingredient to explain the improved core ion confinement observed in Hybrid scenarios or Advanced Tokamak (AT) scenarios with Internal Transport Barriers, two regimes that are considered for ITER operations beyond the standard inductive H-mode regime. This thesis work starts from the above mentioned JET results and from the already developed theoretical models and existing numerical codes, and includes four main items of work, with the purpose of integrating experimental analysis and theory-based numerical modelling of JET experiments, in order to reach predictive capabilities for the future tokamak FAST, a device proposed by the Italian Fusion Association as a possible ITER satellite. First, new experiments have been carried out in JET and analyzed in detail, in order to assess if the cause for ion stiffness reduction is the rotation value or the rotational shear. The data analysis has given as result that it is the absolute value of the rotational shear the key factor for ion stiffness mitigation. This gives the indication for ITER that the necessary condition for reducing the ion stiffness and access improved core confinement regimes is to induce some rotational shear, which may be easier than achieving high absolute values of rotation. Second, a numerical study has been carried out in JET and ITER plasmas to quantify the impact of ion threshold and stiffness on global confinement and fusion power compared to the effect of edge Ti value. This work has the aim of evaluating if threshold and particularly stiffness are indeed two useful control tools for scenario performance optimization. The variation of global confinement has been found quantitatively significant for changes of the ion stiffness, and comparable with the ones due to changes of ion threshold and Ti pedestal height, when they are varied in an experimentally realistic range. In ITER, the calculated fusion power, which is what really matters for a fusion device, is as much affected by variations of ion stiffness as by changes of ion threshold and Ti pedestal height. This work gives the indication that all the three investigated parameters influence comparably the core performances in present and future machines. In particular the quantitative level of ion stiffness, which is a parameter not much considered until now, and assumed or predicted very high in most existing models, can be a useful knob to act upon in order to optimize the scenario performance and must be taken into account for an accurate predictive modelling of future machines. Third, a prediction work for the foreseen scenarios of FAST has been carried out, using a mixture of first-principle models and experiment driven considerations. The results obtained in the two previous steps have led to the conviction that predictive modelling of future devices cannot neglect including toroidal rotation profiles and their effects on transport, which is not common practice in tokamak simulation work. Both H-modes and fully non-inductive AT scenarios have been simulated, predicting profiles of current, ion and electron temperature, density and toroidal rotation. Various heating options have been explored. The simulations have provided a set of FAST scenarios in which fast particle and burning plasma studies can be performed, reaching values of thermal and fast particle energy contents well in line with the needs for exciting meso-scale fluctuations with the same characteristics of those expected in reactor relevant conditions. Fourth, linear gyro-kinetic simulations have been carried out to check the validity of simplified threshold formulae used in simulations in the high toroidal field and high density FAST plasmas. Very good agreement was found between the analytical threshold approximation and the GKW simulations with adiabatic electrons, whilst the threshold with kinetic electrons is slightly lower. The discrepancy is anyway small enough to justify the use of the threshold analytic approximation for FAST simulations, taking into account the other sources of uncertainty linked to various other modelling approximations and to empirical extrapolations from experimental data of existing machines.

Published
2012
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