Feasibility study and CXRS synthetic diagnostic model for COMPASS upgrade based on Cherab and Raysect framework

Tomeš, M.; Carr, M.; Meakins, A.; Imríšek, M.; Jaulmes, F.; Balner, V.; Bogár, K.; Bílková, P.; Weinzettl, V.; Hron, M.; Pánek, R.

doi:10.1016/j.fusengdes.2021.112498

Cited by 5 publications

(6 citation statements)

References 8 publications

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“…The passing fraction f pass is fitted by equation ( 8) with parameters given in (10). This allows us to calculate the provided auxiliary heating power P AUX into the tokamak even if Doppler spectra measurements are not available.…”

Section: Beam Scrapingmentioning

confidence: 99%

“…the ratio P NBI /P tot , where P tot is a result of the spectroscopic measurements in figure 6, represents a fraction of all the fast neutrals produced, which are successfully ionized and confined inside the plasma. This is compared with the expected passing fraction f pass through the narrow port causing the scraping, equations ( 8) and (10), which is based on the beamlet model (figure 13…”

Section: Nbi Power From the Power Balancementioning

confidence: 99%

“…These NBIs are unique for their small beam width, which is beneficial for beam-based diagnostics. Therefore, one of them will become a dedicated diagnostic beam [10]. The second intended to be used for plasma heating, at least in the initial phase of the COMPASS-Upgrade operation, see details in [9].…”

Section: Introductionmentioning

confidence: 99%

“…= c(P tot − p) , f = a + bP tot , P tot = 0.85U beam I beam , (9) c = 0.0258 , p = 320 , a = −1.286 , b = 0.00558 (10). …”

mentioning

confidence: 99%

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Characterisation of the auxiliary heating power delivered by the 40 keV neutral beam injectors on the COMPASS tokamak

Bogár¹,

Varju²,

Havlíček³

et al. 2022

Plasma Phys. Control. Fusion

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Two identical neutral beam injectors (NBI) have been installed on the COMPASS tokamak. Each of them is capable of producing a deuterium (or hydrogen, helium) neutral beam with nominal power of up to 400 kW at 40 keV. Since the COMPASS tokamak is a compact machine the neutral beams’ design was carefully optimized to fit the neutral beam through the narrow ports of the tokamak. However, once the neutral beams are operated out of the scope of their optimal parameters, additional power losses due to the neutral beam scraping occur. The article investigates the amount of power losses due to neutral beam scraping. The losses are calculated by the neutral beam models and measured neutral beams parameters. The calculation results are compared with the measured power delivered into the plasma. There are two different neutral beam models employed. One describes neutral beam as a sum of small beamlets, which are Gaussian-like. Second one describes neutral beam a single Gaussian beam. The amount of the power lost to scraping is determined by both models and compared. Neutral beam parameters, input parameters for both models, are derived from the Doppler-shifted spectra emitted by fast neutral atoms. It is shown that when operating NBIs at nominal parameters, the scraping losses are negligible (<5% ). If the NBIs are operated to far from the nominal parameters, the scraping losses can reach up to ∼60% of the NBI output power. As the highest fractional losses occur with low power NBI, the beam duct is capable to withstand the corresponding power loads. The expected auxiliary heating power PAUX, the power entering the tokamak chamber carried by fast neutrals, is benchmarked against the additional plasma input power observed on the measured plasma parameters PNBI. The additional plasma input power PNBI is derived from the plasma power balance....

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Section: Beam Scrapingmentioning

confidence: 99%

Section: Nbi Power From the Power Balancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…= c(P tot − p) , f = a + bP tot , P tot = 0.85U beam I beam , (9) c = 0.0258 , p = 320 , a = −1.286 , b = 0.00558 (10). …”

mentioning

confidence: 99%

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Characterisation of the auxiliary heating power delivered by the 40 keV neutral beam injectors on the COMPASS tokamak

Bogár¹,

Varju²,

Havlíček³

et al. 2022

Plasma Phys. Control. Fusion

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show abstract

“…The experimental setup was modeled using a ray-tracing simulation environment based on the Python package Raysect [5]. This simulation environment has been previously used to model the 2020 JINST 15 C01022…”

Section: Ray-tracing Simulationmentioning

confidence: 99%

Assessment of tomography signals in view of neural network reconstruction at ISTTOK

et al. 2020

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The detector measurements that serve as a basis for the tomographic reconstruction of plasma radiation profiles can be affected by a number of issues. In this work, we are especially concerned about reflections inside the vessel that appear as direct incidences, when in fact those contributions come from points that are outside the line of sight of a detector. This problem occurs in devices such as ISTTOK, where the surface of the inner vessel acts as an optical system capable of reflecting light. To assess the contribution of those reflections to the detector signals, we used an experimental setup comprising a cylindrical gas-discharge lamp placed at several radial and angular positions inside the vessel. As detectors, we used two photodiode arrays, one placed on the equatorial plane and the other at the top of the vessel. At the same time, we modelled this experimental setup in a ray-tracing simulation software so that, once the experimental data agrees with the simulation data, we can use this simulated environment to study the effect of reflections in realistic plasma profiles. When properly calibrated, such simulated environment can be used to generate large volumes of high-quality data to train a neural network for plasma tomography.

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Development of the diagnostic tools for the COMPASS-U tokamak and plans for the first plasma

Weinzettl

Bílková

Ďuran

et al. 2023

Fusion Engineering and Design

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Feasibility study and CXRS synthetic diagnostic model for COMPASS upgrade based on Cherab and Raysect framework

Cited by 5 publications

References 8 publications

Characterisation of the auxiliary heating power delivered by the 40 keV neutral beam injectors on the COMPASS tokamak

Characterisation of the auxiliary heating power delivered by the 40 keV neutral beam injectors on the COMPASS tokamak

Assessment of tomography signals in view of neural network reconstruction at ISTTOK

Development of the diagnostic tools for the COMPASS-U tokamak and plans for the first plasma

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