Nearing final design of the ITER EC H&amp;CD Upper Launcher

Strauß, D.; Aiello, G.; Bertizzolo, R.; Bruschi, A.; Casal, N.; Chavan, R.; Farina, D.; Figini, L.; Gagliardi, Mario; Goodman, T. P.; Grossetti, G.; Heemskerk, C.J.M.; Henderson, M.; Kasparek, W.; Koning, J.F.; Landis, J.‐D.; Leichtle, D.; Meier, Andreas; Moro, A.; Nowak, S.; Pacheco, Jardel Pizzatto; Platania, P.; Plaum, B.; Poli, E.; Ramseyer, Florian; Ronden, D.; Saibene, G.; Más-Sanchez, A.; Silva, Phillip Santos; Sauter, O.; Scherer, T.; Schreck, S.; Sozzi, C.; Spaeh, P.; Vagnoni, Matteo; Vaccaro, A.; Weinhorst, B.

doi:10.1016/j.fusengdes.2018.11.013

Cited by 17 publications

(4 citation statements)

References 19 publications

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“…In particular the equatorial launcher, which is foreseen for central EC-heating, will not be available. This means that for the initial plasma breakdown the upper launcher [1] has to be used.…”

Section: Introductionmentioning

confidence: 99%

Calculations for the optical system for the first ITER plasma

2023

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A dedicated optical system is designed for the breakdown of the first ITER plasma, when the machine will not be equipped with the equatorial ECRH-launcher. Seven beams from the upper launcher will be transmitted via several in-vessel mirrors through the resonance layer to a beam-dump. The whole system was simulated with the PROFUSION package to obtain the beam parameters, estimate spill-over effects and determine the required polarization in the launcher in order to have X-mode polarization in the resonance.

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Section: Introductionmentioning

confidence: 99%

Calculations for the optical system for the first ITER plasma

2023

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“…• Front steering (e.g. ITER upper launcher [10,11]) involves fast tilting of water-cooled heavy mirrors close to the plasma. The mechanics must tolerate high neutron loading.…”

Section: Introductionmentioning

confidence: 99%

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

Aiello

Avramidis

et al. 2021

Fusion Engineering and Design

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An Electron Cyclotron Wave (ECW) system will be used in the European DEMO for the stabilization of Neoclassical Tearing Modes (NTMs). In order to avoid movable mirrors in the harsh environment close to the plasma and to simplify the NTM launcher integration, the tuning of the ECW deposition location can be achieved by launching frequency-tunable ECWs from fixed mirrors while the frequency is tuned in discrete steps of 2-3 GHz. An overview of the frequency step-tunable ECW system for NTM stabilization is presented. The design considerations are discussed based on the current DEMO baseline parameters and the status of technologies. A simulation of NTM stabilization with an idealized frequency tunable ECW system on an analytical NTM model is shown. The simulation takes into account a realistic tuning speed based on the present technology and considers the current NTM launcher configurations in DEMO. A simple sweeping strategy is adapted for the control of frequency. Various uncertainties, which will affect the feasibility, need to be further investigated.

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“…This phenomenon is greatly exploited in the heating of fusion plasmas. 9,10 While the aforementioned considerations and models approximately capture the global phenomena, they do not provide any detailed spatiotemporal information. Spatially resolved kinetic models may accurately predict these dynamics, limited by their computational requirements.…”

Section: Introductionmentioning

confidence: 99%

Kinetic simulation of electron cyclotron resonance assisted gas breakdown in split-biased waveguides for ITER collective Thomson scattering diagnostic

et al. 2021

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For the measurement of the dynamics of fusion-born alpha particles E a 3:5 MeV in ITER using collective Thomson scattering (CTS), safe transmission of a gyrotron beam at mm-wavelength (1 MW, 60 GHz) passing the electron cyclotron resonance (ECR) in the in-vessel tokamak "port plug" vacuum is a prerequisite. Depending on neutral gas pressure and composition, ECR-assisted gas breakdown may occur at the location of the resonance, which must be mitigated for diagnostic performance and safety reasons. The concept of a split electrically biased waveguide (SBWG) has been previously demonstrated in C.P. Moeller, U.S. patent 4, 687,616 (1987). The waveguide is longitudinally split and a kV bias voltage is applied between the two halves. Electrons are rapidly removed from the central region of high radio frequency electric field strength, mitigating breakdown. As a full scale experimental investigation of gas and electromagnetic field conditions inside the ITER equatorial port plugs is currently unattainable, a corresponding Monte Carlo simulation study is presented. Validity of the Monte Carlo electron model is demonstrated with a prediction of ECR breakdown and the mitigation pressure limits for the above-quoted reference case with 1 H 2 (and pollutant high Z elements). For the proposed ITER CTS design with a 88.9 mm inner diameter SBWG, ECR breakdown is predicted to occur down to a pure 1 H 2 pressure of 0.3 Pa, while mitigation is shown to be effective at least up to 10 Pa using a bias voltage of 1 kV. The analysis is complemented by results for relevant electric/magnetic field arrangements and limitations of the SBWG mitigation concept are addressed.

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Nearing final design of the ITER EC H&CD Upper Launcher

Cited by 17 publications

References 19 publications

Calculations for the optical system for the first ITER plasma

Calculations for the optical system for the first ITER plasma

Basic design considerations for a frequency step-tunable electron cyclotron wave system to suppress NTMs in DEMO

Kinetic simulation of electron cyclotron resonance assisted gas breakdown in split-biased waveguides for ITER collective Thomson scattering diagnostic

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