Real time capable infrared thermography for ASDEX Upgrade

Sieglin, B.; Faitsch, M.; Herrmann, A.; Brucker, B.; Eich, T.; Kammerloher, L.; Martinov, S.

doi:10.1063/1.4935580

Cited by 76 publications

(60 citation statements)

References 6 publications

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“…The temperature evolution of both strike zones is measured using two infrared (IR) thermography systems [14]. Heat flux is calculated using the THEODOR code [36,37]. Target electron temperature T e,t and density n e,t are estimated using Langmuir probes (LP) [38].…”

Section: Upstream and Target Conditions As Function Of Upper Triangulmentioning

confidence: 99%

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Faitsch

Maurizio

Gallo

et al. 2018

Plasma Phys. Control. Fusion

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This paper reports on experimental observations on TCV with a scan in upper triangularity δup, including negative triangularity, focusing on the power fall-off length λq in L-Mode. The upper triangularity is scanned from -0.28 to 0.47. Smaller λ out q is measured at the outer divertor target for decreasing δup together with higher edge temperature T e,edge leading to increased confinement. This effect is observed for both magnetic drift directions for discharges in deuterium and helium. In helium larger λq values are observed compared to deuterium. The power fall-off length at the inner divertor target λ in q has a non monotonic behaviour with changing triangularity. The largest values are around δup = 0. The ratio λ in q /λ out q increases for decreasing δup for positive triangularity and is approximately constant for negative triangularity. λ out q is compared to available scaling laws. Partial agreement is only observed for a scaling law containing a proxy for T e,edge at ASDEX Upgrade [Sieglin, PPCF 2016]. Extending this scaling to TCV and using T e,edge at ρ pol = 0.95 suggests that λ out q is independent of machine size λ L−Mode q [mm] = 165 · B pol [T] −0.66 · A[u] −0.15 · T e,edge [eV] −0.93 · R[m] −0.03 . Possible explanations for smaller λ out q for decreasing δup is a reduction in turbulence or a direct effect of increasing T e,edge .

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Section: Upstream and Target Conditions As Function Of Upper Triangulmentioning

confidence: 99%

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Faitsch

Maurizio

Gallo

et al. 2018

Plasma Phys. Control. Fusion

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“…For the study of the heat transport in the scrape-off layer (SOL) L-Mode discharges in ASDEX Upgrade with stable divertor conditions were conducted. The heat flux profiles on target are measured using infrared (IR) thermography [4]. The values for S and λ q are obtained by fitting the model (Equation 1) to the data, taking into account the poloidal flux expansion f x [1].…”

Section: Introductionmentioning

confidence: 99%

Investigation of scrape-off layer and divertor heat transport in ASDEX Upgrade L-mode

Sieglin

Eich

Faitsch

et al. 2016

Plasma Phys. Control. Fusion

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Power exhaust is one of the major challenges for the development of a fusion power plant. Predictions based upon a multi machine database give a scrapeoff layer power fall-off length λ q ≤ 1 mm for large fusion devices such as ITER. The power deposition profile on the target is broadened in the divertor by heat transport perpendicular to the magnetic field lines. This profile broadening is described by the power spreading S. Hence both λ q and S need to be understood in order to estimate the expected divertor heat load for future fusion devices. For the investigation of S and λ q L-Mode discharges with stable divertor conditions in hydrogen and deuterium were conducted in ASDEX Upgrade. A strong dependence of S on the divertor electron temperature and density is found which is the result of the competition between parallel electron heat conductivity and perpendicular diffusion in the divertor region. For high divertor temperatures it is found that the ion gyro radius at the divertor target needs to be considered. The dependence of the in/out asymmetry of the divertor power load on the electron density is investigated. The influence of the main ion species on the asymmetric behaviour is shown for hydrogen, deuterium and helium. A possible explanation for the observed asymmetry behaviour based on vertical drifts is proposed.

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“…During the course of the campaign, also a result of our measurements, this was increased to 4 MJ. Infrared camera systems are used in magn etic fusion experiments, world-wide, to measure heat loads on vessel components [3][4][5][6]. Due to the helical symmetry with five modules in W7-X, there will eventually be on the order of 10-20 camera systems (2 or more IR cameras viewing in each module) to cover the entire vessel for long pulse operation, all with real-time analysis and large data streams.…”

Section: International Atomic Energy Agencymentioning

confidence: 99%

Limiter observations during W7-X first plasmas

et al. 2017

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During the first operational phase (referred to as OP1.1) of the new Wendelstein 7-X (W7-X) stellarator, five poloidal graphite limiters were mounted on the inboard side of the vacuum vessel, one in each of the five toroidal modules which form the W7-X vacuum vessel. Each limiter consisted of nine specially shaped graphite tiles, designed to conform to the last closed field line geometry in the bean-shaped section of the standard OP1.1 magnetic field configuration (Sunn Pedersen et al 2015 Nucl. Fusion 55 126001). We observed the limiters with multiple infrared and visible camera systems, as well as filtered photomultipliers. Power loads are calculated from infrared (IR) temperature measurements using THEODOR, and heating patterns (dual stripes) compare well with field line mapping and EMC3-EIRENE predictions. While the poloidal symmetry of the heat loads was excellent, the toroidal heating pattern showed up to a factor of 2× variation, with peak heat loads on Limiter 1. The total power intercepted by the limiters was up to ~60% of the input ECRH heating power. Calorimetry using bulk tile heating (measured via post-shot IR thermography) on Limiter 3 showed a difference between short high power discharges, and longer lower power ones, with regards to the fraction of energy deposited on the limiters. Finally, fast heating transients, with frequency >1 kHz were detected, and their visibility was enhanced by the presence of surface coatings which developed on the limiters by the end of the campaign.

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Real time capable infrared thermography for ASDEX Upgrade

Cited by 76 publications

References 6 publications

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Dependence of the L-Mode scrape-off layer power fall-off length on the upper triangularity in TCV

Investigation of scrape-off layer and divertor heat transport in ASDEX Upgrade L-mode

Limiter observations during W7-X first plasmas

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