ECE for NTM control on ITER

Brand, H. van den; Baar, M.R. de; Cardozo, N.J. Lopes; Westerhof, E.

doi:10.1051/epjconf/20123203004

Cited by 6 publications

(6 citation statements)

References 15 publications

(23 reference statements)

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“…The real challenge for the ITER control system (for scenarios in which ECCD is applied after NTM detection and not pre-emptively) will be rather to determine [57,58] and reach the correct location in a sufficiently short time, so as to avoid mode locking [53,55]. The plasma parameters considered here have been taken from a snapshot (close to the end of the current flattop phase) of a simulated plasma discharge for the standard I p = 15 MA, Q = 10 ITER scenario [59], while the ECCD parameters have been computed with the code TORBEAM [60] (a detailed analysis of the ECCD performance for this and other simulated ITER discharges will be presented in Ref.…”

Section: Below)mentioning

confidence: 99%

“…This means that even in the case of no broadening, the steering mechanism should ensure sufficient compensation for possible misalignments (a more detailed analysis of this issue will be presented elsewhere [56]). The real challenge for the ITER control system (for scenarios in which ECCD is applied after NTM detection and not pre-emptively) will be rather to determine [57,58] and reach the correct location in a sufficiently short time, so as to avoid mode locking [53,55].…”

Section: Impact Of Profile Broadening and Misalignment On The Power R...mentioning

confidence: 99%

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On recent results in the modelling of neoclassical-tearing-mode stabilization via electron cyclotron current drive and their impact on the design of the upper EC launcher for ITER

et al. 2015

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Electron cyclotron wave beams injected from a launcher placed in the upper part of the vessel will be used in ITER to control MHD instabilities, in particular neoclassical tearing modes (NTMs). Simplified NTM stabilization criteria have been used in the past to guide the optimization of the launcher. Their derivation is reviewed in this paper and their range of applicability clarified. Moreover, possible effects leading to a deterioration of the predicted performance are discussed. Particularly critical in this context is the broadening of the EC deposition profiles. It is argued that the most detrimental effect for ITER is likely to be the scattering of the EC beams from density fluctuations due to plasma turbulence, resulting in a beam broadening by about a factor of two. The combined impact of these effects with that of beam misalignment (with respect to the targeted surface) is investigated by solving the Rutherford equation in a form that retains the most relevant terms. The perspectives for NTM stabilization in the Q = 10 ITER scenario are discussed.

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Section: Below)mentioning

confidence: 99%

Section: Impact Of Profile Broadening and Misalignment On The Power R...mentioning

confidence: 99%

On recent results in the modelling of neoclassical-tearing-mode stabilization via electron cyclotron current drive and their impact on the design of the upper EC launcher for ITER

et al. 2015

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“…If discrepancies in some time sections are found, diagnostic data could be streamed remotely, and more accurate (but computationally expensive) analyses could be performed to quickly drill down on potential causes. For example, diagnostics such as electron cyclotron emission and magnetics could be analyzed for magnetohydrodynamic (MHD) mode activity [e.g., neoclassical tearing modes 17,18 (NTMs)] and more complete MHD simulations (e.g., including nonlinear coupling of NTMs and internal kink modes 19 ) launched on remote compute resources to more accurately determine mode growth and stability. With the more accurate information in hand, the faster integrated modeling simulation can be updated, and operators and scientists armed with the updated data can make better determinations of which segments to select for the next plasma discharge.…”

Section: Federated Frameworkmentioning

confidence: 99%

A Framework for International Collaboration on ITER Using Large-Scale Data Transfer to Enable Near-Real-Time Analysis

Churchill

Chang

Choi

et al. 2021

Fusion Science and Technology

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The global nature of the ITER project along with its projected approximately petabyte-per-day data generation presents not only a unique challenge but also an opportunity for the fusion community to rethink, optimize, and enhance our scientific discovery process. Recognizing this, collaborative research with computational scientists was undertaken over the past several years to create a framework for large-scale data movement across wide-area networks to enable global near-real-time analysis of fusion data. This would broaden the available computational resources for analysis/simulation and increase the number of researchers actively participating in experiments.An official demonstration of this framework for fast, large data transfer and real-time analysis was carried out between the KSTAR tokamak in Daejeon, Korea, and Princeton Plasma Physics Laboratory (PPPL) in Princeton, New Jersey. Streaming large data transfer, with near-real-time movie creation and analysis of the KSTAR electron cyclotron emission imaging data, was performed using the Adaptable Input Output (I/O) System (ADIOS) framework, and comparisons were made at PPPL with simulation results from the XGC1 code. These demonstrations were made possible utilizing an optimized network configuration at PPPL, which achieved over 8.8 Gbps (88% utilization) in throughput tests from the National Fusion Research Institute to PPPL. This demonstration showed the feasibility for large-scale data analysis of KSTAR data and provides a nascent framework to enable use of globally distributed computational and personnel resources in pursuit of scientific knowledge from the ITER experiment.

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“…The isolated input port of the diplexer can be used to receive ECE radiation from the plasma by sharing the NTM launchers with the (forward) ECRH [27]. After appropriate processing, the in-line ECE signal can be implemented into the control system of the experiment to steer the launchers for optimum deposition of the power in the NTM islands [28]. This port is also available for using the connected launcher for any microwave diagnostics operating around the EC frequency.…”

Section: Outlook: Options For Applications In Large-scale Ecrh Systemsmentioning

confidence: 99%

NTM stabilization by alternating O-point EC current drive using a high-power diplexer

et al. 2016

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At the tokamak ASDEX Upgrade, experiments to stabilize neoclassical tearing modes (NTMs) by electron cyclotron (EC) heating and current drive in the O-points of the magnetic islands were performed. For the first time, injection into the O-points of the revolving islands was performed via a fast directional switch, which toggled the EC power between two launchers synchronously to the island rotation. The switching was performed by a resonant diplexer employing a sharp resonance in the transfer function, and a small frequency modulation of the feeding gyrotron around the slope of the resonance. Thus, toggling of the power between the two outputs of the diplexer connected to two articulating launchers was possible. Phasing and control of the modulation were performed via a set of Mirnov coils and appropriate signal processing. In the paper, technological issues, the design of the diplexer, the tracking of the diplexer resonance to the gyrotron frequency, the generation and processing of control signals for the gyrotron, and the typical performance concerning switching contrast and efficiency are discussed. The plasma scenario is described, and plasma experiments are presented, where the launchers scanned the region of the resonant surface continuously and also where the launchers were at a fixed position near to the q = 1.5-surface. In the second case, complete stabilization of a 3/2 NTM could be reached. These experiments are also seen as a technical demonstration for the applicability of diplexers in large-scale ECRH systems.

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ECE for NTM control on ITER

Cited by 6 publications

References 15 publications

On recent results in the modelling of neoclassical-tearing-mode stabilization via electron cyclotron current drive and their impact on the design of the upper EC launcher for ITER

On recent results in the modelling of neoclassical-tearing-mode stabilization via electron cyclotron current drive and their impact on the design of the upper EC launcher for ITER

A Framework for International Collaboration on ITER Using Large-Scale Data Transfer to Enable Near-Real-Time Analysis

NTM stabilization by alternating O-point EC current drive using a high-power diplexer

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