Ray Trace Study for Visible Spectroscopy Reference System (VSRS) Diagnostics in ITER

Kajita, Shin; Bock, Maarten De; Desjardins, Michel; Barnsley, R.

doi:10.1585/pfr.14.1405042

Cited by 4 publications

(4 citation statements)

References 21 publications

(28 reference statements)

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“…As was discussed previously [16], a slight increase in 𝜃 𝑒 could degrade the image quality significantly. Of course, an increase in the diffuse reflection decreases the detector intensity.…”

Section: Divergencementioning

confidence: 70%

Performance of first mirrors for divertor impurity monitor in ITER: compensation of misalignment and effect of beam divergence

Kajita¹,

Ogawa²,

Kitazawa³

et al. 2020

J. Inst.

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We investigated feasibility of an alignment method using first mirrors of the divertor impurity monitor (DIM) in ITER based on ray tracing analysis. A misalignment could occur between the divertor cassette and measurement system. It is shown that the misalignment can be compensated to some extent by rotating the first mirror. The maximum compensable misalignment and the required accuracy in the alignment are discussed. It is likely that the surface roughness of the first mirrors gradually increases during ITER operation. We investigated the required quality of the first mirror as focusing on the beam divergence using the ray tracing model. Moreover, to check the performance, helium plasma irradiation was performed on molybdenum mirror samples, and the beam divergence was measured using a laser and a detector. Based on the simulations and experiments, it is shown that the helium effect does not harm the performance of the mirror when the mirror temperature is less than 800 K.

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Section: Divergencementioning

confidence: 70%

Performance of first mirrors for divertor impurity monitor in ITER: compensation of misalignment and effect of beam divergence

Kajita¹,

Ogawa²,

Kitazawa³

et al. 2020

J. Inst.

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“…It is one of the first systems to issue a warning when the conditions of the nuclear fusion plasma are out of operational bounds and damage to the machine is imminent. As many of ITER's subsystems, the VSRS implements exotic technologies and materials, and its design involves highly specialized scientific analyses (Kajita et al, 2019;Ushakov et al, 2020). Our goal is to improve the organizational communication by identifying critical interfaces that are managed by multiple parties.…”

Section: Demonstrationmentioning

confidence: 99%

Challenges Of Big-science: A Matrix-based Interface Model To Manage Technical Integration Risks In Multi-organizational Engineering Projects

Beernaert¹,

Etman²,

Bock³

et al. 2022

DS 121: Proceedings of the 24th International DSM Conference (DSM 2022), Eindhoven, the Netherlands, October, 11 - 13, 2022

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Tomorrow's big science systems are in development today. Success depends on global collaboration in which multiple international parties produce unique assemblies. Inter-organizational barriers, interests and technical conflicts often complicate the design and realization process. It is especially difficult to manage a system's interfaces over such boundaries. We propose a model-based approach to support integrators in such situations. Combining a system architecture model, Integration Readiness Levels (IRLs) and a network of actors, we can derive a newly introduced Collaborative Interface Risk Index (CIRI) that highlights risky interfaces, the organizational patterns that are required for successful integration and a progress indicator that tracks how many interfaces have been defined sufficiently. We demonstrate the method for one of ITER's diagnostic subsystems, which is being developed by six distributed organizations. The result is a Multi-Domain Matrix (MDM) that gives a complete overview on the complexity and risks of the collaborative engineering project.

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“…Here R is the major radius and r e is the classical electron radius. The second term on the right-hand side of equation (10) is the synchrotron loss and has been taken into account for the calculation of E max RE . The calculated E max RE for the RE#1 scenario data increases from 0 to 23 MeV at 2.4 s with the RE current increasing from 0 to 630 kA during this time period.…”

Section: Simulation Of Runaway Electron Formation and Their Detectionmentioning

confidence: 99%

“…The aim of this paper is to assess if this set of diagnostics is capable to detect the early plasma formation process, diagnose it and importantly that this is possible in realtime, such that it can be assessed if the signals are of use for the ITER PCS. Those ITER FP diagnostics that provide realtime data are: the magnetic diagnostics [6], H α visible spectroscopy [7], interferometry [8], hard x-ray monitor (HXRM) [9], visible camera [10] and Penning gauges. The latter diagnostic has been omitted form the assessment here, because this system does not directly diagnose the plasma, although it provides real-time data relevant to the overall plasma initiation process, importantly the pre-fill pressure.…”

Section: Introductionmentioning

confidence: 99%

Development of synthetic diagnostics for ITER First Plasma operation

Sinha

Vries

Zabeo

et al. 2021

Plasma Phys. Control. Fusion

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ITER First Plasma (FP) operation aims to produce a plasma with current higher than 100 kA for a duration longer than 100 ms. However, the low values of plasma density and temperature associated with the initiation phase make it difficult to diagnose the plasma accurately. It is therefore essential to develop models for the available diagnostics for ITER FP operation in order to determine the necessary measurement ranges for plasma initiation and use them as inputs for controller development and assessment within the plasma control system (PCS). The use of accurate diagnostic models also helps to optimally prepare for, and analyse, ITER FP operation. A model developed for the H α main chamber visible spectroscopy for FP shows that it is possible to measure H α emission soon after breakdown for plasma temperatures higher than 3 eV and average plasma densities higher than 10 17 m −3 . The diagnostic model for the interferometer shows that for the proposed ITER FP scenarios, accurate measurements are possible for average plasma densities higher than 5 × 10 17 m −3 . The results from modelling of the hard x-ray monitor demonstrate that it can provide signals useful for runaway electron detection and can measure current levels typically down to 3 kA. Thus, these measurements can thus be used effectively by the PCS for runaway electron (RE) detection during FP operation. Improved diagnosis of the plasma state deducing, for example, parameters such as the plasma size and position, is possible by combining the measurements from the different FP diagnostics (density interferometer polarimeter and H α main chamber visible spectroscopy), which will be available for ITER FP operation.

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Ray Trace Study for Visible Spectroscopy Reference System (VSRS) Diagnostics in ITER

Cited by 4 publications

References 21 publications

Performance of first mirrors for divertor impurity monitor in ITER: compensation of misalignment and effect of beam divergence

Performance of first mirrors for divertor impurity monitor in ITER: compensation of misalignment and effect of beam divergence

Challenges Of Big-science: A Matrix-based Interface Model To Manage Technical Integration Risks In Multi-organizational Engineering Projects

Development of synthetic diagnostics for ITER First Plasma operation

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