Status and future development of Heating and Current Drive for the EU DEMO

Tran, M.Q.; Agostinetti, P.; Aiello, G.; Avramidis, Konstantinos A.; Baiocchi, B.; Barbisan, M.; Bobkov, V.; Briefi, S.; Bruschi, A.; Chavan, R.; Chelis, Ioannis; Day, C.; Delogu, R.; Ell, Benjamin; Fanale, F.; Fassina, A.; Fantz, U.; Faugel, H.; Figini, L.; Fiorucci, D.; Friedl, R.; Franke, T.; Gantenbein, G.; Garavaglia, S.; Granucci, G.; Hanke, S.; Hogge, J.‐P.; Hopf, C.; Kostic, A.; Illy, S.; Ioannidis, Zisis C.; Jelonnek, John; Jin, Jianbo; Latsas, George P.; Louche, F.; Maquet, V.; Maggiora, Riccardo; Messiaen, A.; Milanesio, Daniele; Mimo, A.; Moro, A.; Ochoukov, R.; Ongena, J.; Pagonakis, I.; Peponis, Dimitrios V.; Pimazzoni, A.; Ragona, R.; Rispoli, N.; Ruess, Tobias; Rzesnicki, T.; Scherer, T.; Spaeh, P.; Starnella, G.; Strauß, D.; Thumm, M.; Tierens, W.; Tigelis, I. G.; Tsironis, C.; Usoltceva, M.; Eester, D. Van; Veronese, F.; Vincenzi, P.; Wagner, F.; Wu, Chuanren; Zeus, F.; Zhang, W.

doi:10.1016/j.fusengdes.2022.113159

Cited by 33 publications

(16 citation statements)

References 92 publications

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“…The other inner surfaces (excluding the acceleration system) are protected by a molybdenum foil; multipole magnet systems reduce the plasma-surface interaction. The source needs to be operated at gas pressure levels that are higher than the 0.3 Pa target level for ITER (and likely DEMO) [[8]- [10]], because the mean free path of electrons must be kept within the dimensions of the source, which are smaller than other ITER/DEMO relevant negative ion sources [[8]- [10]]. The negative ions are extracted through a 4-grid system (plasma grid -PG, extraction grid -EG, post acceleration grid -PA, repeller grid -REP); co-extracted electrons are mostly dumped to the EG thanks to the magnetic field generated by its embedded magnets.…”

Section: Introductionmentioning

confidence: 99%

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Barbisan

Delogu

Pimazzoni

et al. 2022

IEEE Trans. Plasma Sci.

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The compact radio frequency negative ion source NIO1 (Negative Ion Optimization phase 1) has been designed, built and operated by Consorzio RFX and INFN-LNL in order to study and optimize the production and acceleration of Hions in continuous operation. In 2020 Cs was evaporated in the source to increase the total extracted ion current. After an initial reduction of extracted electron to ion ratio and subsequently an increase of extracted negative ion current, the source performances progressively worsened, because of the excessive amount of Cs evaporated in the source; the extracted electron to ion ratio increased from below 1 to more than 10, while ion current density reduced from max. 67 A/m 2 ion current to not more than 30 A/m 2 ). The paper presents the experimental observations collected during Cs evaporation (reduction of plasma light, Cs emission and Hβ/Hγ ratio, etc.) that can help stopping the process before an excessive amount of Cs is introduced in the source. The paper also reports the cleaning techniques tested to remove the Cs excess by the action of hydrogen or argon plasmas; while argon was predictably more effective in surface sputtering, a 3 h Ar plasma treatment was not sufficient to recover from overcesiation.

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Section: Introductionmentioning

confidence: 99%

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Barbisan

Delogu

Pimazzoni

et al. 2022

IEEE Trans. Plasma Sci.

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“…No information on net toroidal plasma rotation v i is available in the adopted equilibrium, nor is any heating or current drive from neutral beam injection (NBI) envisaged in the adopted plasma scenario or in the current plans for the baseline heating system of DEMO in general [23]. Some intrinsic turbulence-driven rotation might be expected in DEMO even in the absence of auxuliary torque input [24][25][26][27]; however, since this is challenging to predict quantitatively, we have here generally assumed v i = 0 when generating or inverting the synthetic spectra.…”

Section: Plasma Scenario and Raytracingmentioning

confidence: 99%

Core ion measurements with collective Thomson scattering for DEMO burn control

Rasmussen,

Korsholm

2024

Nucl. Fusion

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DEMO burn control will require measurements of a range of plasma parameters, but the suite of feasible diagnostics for this purpose is limited. Here we assess the accuracy with which a collective Thomson scattering (CTS) diagnostic can provide key measurements for burn control in the planned European DEMO (EU-DEMO). This is based on estimated signal-to-noise ratios for a conceptual diagnostic design and trial fits to synthetic DEMO CTS spectra. We show that a diagnostic with a single probe- and receiver beam setup will be able to provide simultaneous measurements of core fusion alpha density and ion temperature to mean accuracies better than 5 and 10%, respectively, along with detecting intrinsic toroidal rotation velocities down to within ∼5 km s-1. Adding a second CTS receiver view furthermore enables inference of the core fuel-ion ratio, allowing discrimination between, e.g., a 50/50% and 55/45% D/T mixture, while also providing useful information on the thermalized He content. A DEMO CTS diagnostic would thus be able to monitor fusion alpha densities as well as anomalous transport of fast alphas and heat from the plasma core, quantify plasma rotation for confinement enhancement, and track the core isotope mix for optimum fusion performance. This versatility makes such a diagnostic a potentially valuable tool for real-time burn control on DEMO.

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“…Among the auxiliary systems adopted in present-day experiments towards the realisation of controlled nuclear fusion with magnetic confinement, Ion Cyclotron (IC) antennas are certainly one of the most promising options to deliver high power to the plasma. As a matter of fact, IC antennas are currently installed and routinely operated in almost all the existing fusion experiments and are foreseen for the next generation of tokamaks like ITER, SPARC [1] and DEMO [2]. An IC system is to be designed also for the Divertor Tokamak Test facility (DTT) [3][4][5], a new tokamak under realization at the ENEA Frascati Research Center.…”

Section: Motivation and Backgroundmentioning

confidence: 99%

The tunable resonant IC antenna concept and its design for DTT experiment

Milanesio,

Galindo Huertas,

Ceccuzzi

et al. 2023

Nucl. Fusion

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The intrinsic poor loading of Ion Cyclotron (IC) plasma-facing antennas makes the use of Tuning and Matching Systems (TMS) a necessity. The antenna plus TMS is a resonant system; in the TMS and access lines high voltages (tens of kV) must be accounted for in the unavoidable unmatched part of the feeding lines. In this work, we propose and test an innovative type of IC launcher; it is based on achieving resonance of the self-standing antenna, i.e. without the TMS. A mechanical full-metal tuning mechanism is described and demonstrated to allow wide-band operation. A systematic analysis of possible antenna topologies has led to identifying a structure that can allow good impedance matching along with compliance with maximum electric field constraints.Most of the design is carried out using a simplified plasma and a commercial analysis tool and then validated with a realistic plasma using TOPICA code.

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Status and future development of Heating and Current Drive for the EU DEMO

Cited by 33 publications

References 92 publications

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Cs Evaporation in a Negative Ion Source and Cs Cleaning Tests by Plasma Sputtering

Core ion measurements with collective Thomson scattering for DEMO burn control

The tunable resonant IC antenna concept and its design for DTT experiment

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