Spatial distribution measurement of atomic radiation with an astigmatism-corrected Czerny-Turner-type spectrometer in the Large Helical Device

Goto, M.; Morita, S.

doi:10.1063/1.2216987

Cited by 29 publications

(22 citation statements)

References 8 publications

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“…Distribution of the plasma source in Fig. 4(c) reflects those processes and consistent with observation of H α radiation [12]. • with open divertor configuration.…”

Section: Simulation Results and Discussionsupporting

confidence: 80%

First EMC3‐EIRENE Simulations with Divertor Legs of LHD in Realistic Device Geometry

Kawamura

Feng

Kobayashi

et al. 2014

Contrib. Plasma Phys.

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An extended mesh system for EMC3-EIRENE has been developed to simulate peripheral plasma including the ergodic and the divertor leg regions of LHD. Both the open and the closed divertor configurations are available. A series of simulations for 8MW input power, five different electron densities at the LCFS (last closed flux surface) and the open/closed configurations were carried out. Approximately 10 times larger neutral pressure was observed under the dome structure compared with the open configuration, which is in good agreement with experimental measurements. In the case of the closed configuration, the leg regions have a large contribution of ionization to hydrogen recycling. In the case of high density discharges, however, electron temperature in the legs becomes low and the major contribution of ionization moves to the ergodic region. Significant influence of configurations is observed in the inboard side of LHD, where closed divertor components are installed but little influence is seen near the LCFS.

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“…Distribution of the plasma source in Fig. 4(c) reflects those processes and consistent with observation of H α radiation [12]. • with open divertor configuration.…”

Section: Simulation Results and Discussionsupporting

confidence: 80%

First EMC3‐EIRENE Simulations with Divertor Legs of LHD in Realistic Device Geometry

Kawamura

Feng

Kobayashi

et al. 2014

Contrib. Plasma Phys.

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“…16. ͑Color online͒ ͑a͒ Chord-integrated bremsstrahlung intensity, ͑b͒ bremsstrahlung emissivity after Abel inversion for two different fitting curves, ͑c͒ normalized errors of intensity ͑solid circles͒, Err I = ͑I fit1 -I fit2 ͒ / I fit1 , and emissivity ͑open circles͒, Err = ͑ fit1 -fit2 ͒ / fit1 , between two fitting profiles.…”

Section: Analysis Of Z Eff Profilementioning

confidence: 99%

Z eff profile diagnostics using visible bremsstrahlung continuum for nonaxisymmetric plasmas with finite β in large helical device

Zhou

Morita

Goto

et al. 2010

Journal of Applied Physics

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An astigmatism-corrected Czerny–Turner-type visible spectrometer coupled with a charge-coupled device has been installed in large helical device (LHD) to measure visible bremsstrahlung continuum. A full vertical profile has been observed from the elliptical plasmas at horizontally elongated plasma cross section through a 44 fiber parallel array with vertical observation length of ∼1 m. Line emissions can be easily eliminated by use of the visible spectrometer instead of an interference filter. A nonmonotonic bremsstrahlung emission profile, which is originated in the thick ergodic layer surrounding the main plasma, has been observed for normal discharges in all the magnetic configurations of LHD. After analyzing the detailed structure, the lower half of the vertical bremsstrahlung emission profile is found to be free of the strong edge bremsstrahlung emission in inwardly shifted magnetic configurations (Rax≤3.60 m). The nonmonotonic bremsstrahlung emission disappeared in extremely high-density discharges (ne≥1014 cm−3) because of the reduction of the plasma outside boundary. When the local emissivity is calculated using Abel inversion, the solution is very sensitive to the distortion of the magnetic surface structure. The influence of the magnetic surface distortion based on the finite β effect is examined as error estimation in addition to unclear edge plasma boundary due to the presence of the ergodic layer. The result indicates that the determination of the normalized minor radius for each observation chord gives a larger influence on the Abel inversion rather than the determination of the chord length. When the observed chord-integrated bremsstrahlung intensity profile is flat, the resultant uncertainty seen in the bremsstrahlung emissivity profile becomes large, in particular, at the plasma center. The Zeff profile calculated with consideration of density and temperature profiles is verified in neutral-beam-heated discharges with H2 and C pellet injections, where the Zeff values should be close to 1 and 6, respectively. Analysis on the flat and hollow electron density profiles results in a fairly flat Zeff profile.

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“…La óptica externa forma imagen de una escena sobre la rendija de entrada del sistema dispersivo que separa el espectro de la luz proveniente de dicha rendija en ángulos diferentes en función de su longitud de onda en una dirección perpendicular a la misma y forma imagen sobre la unidad de detención. Entre algunos de los sistemas estudiados y utilizados como unidad dispersiva en un sensor hiperespectral tipo pushbroom, se pueden destacar el sistema Offner [13][14][15][16], el sistema Dyson [17,18], los sistemas PGP (Prism-Grating-Prism) [19,20] o modificaciones del sistema Czerny-Turner [21,22]. Fig.2.…”

Section: A Espectrómetros De Imagen Dispersivos Tipo Pushbroom: Siunclassified

Offner imaging spectrometers

Carballo¹,

Núñez²

2017

Opt. Pura Apl.

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ABSTRACT:A hyperspectral sensor or imaging spectrometer is a device that collects spatial and spectral information in hundreds of contiguous and closely spectral bands. Hyperspectral imagers have many applications in several areas such as agriculture, geology, oceanography, forestry, medicine, colorimetry, security, military and others. Most of the existing hyperspectral systems were developed considering satellite or high altitude flying aircrafts applications. However, the specific development of these technologies allows their use in many other less expensive applications. In this context, the work presented in this thesis allows building high quality and low cost Offner imaging spectrometers. Rapid and efficient methods were used for the design, assembly and characterization of this type of spectrometers. Two laboratory setups developed from analytical model-based designs have been assembled showing high spectral and spatial resolutions and low distortions without specific aberrations corrected gratings nor non-spherical elements.Key words: Imaging spectrometry, Offner spectrometer, Optical design. RESUMEN:Un sensor hiperespectral o espectrómetro de imagen es un dispositivo que recoge información espacial y espectral en cientos de bandas contiguas y espectralmente estrechas. Los sensores hiperespectrales tienen muchas aplicaciones en diversas áreas como agricultura, geología, oceanografía, silvicultura, medicina, colorimetría, seguridad o aplicaciones militares entre otras. La mayor parte de los equipos hiperespectrales existentes fueron construidos pensando en aplicaciones desde satélites y/o aviones sobrevolando a gran altitud. No obstante, el desarrollo específico de estas tecnologías permite su uso en muchas otras aplicaciones con menor presupuesto. En este contexto, el trabajo presentado en esta de tesis doctoral permite la construcción de espectrómetros de imágenes Offner de alta calidad y bajo coste mediante métodos rápidos y eficientes de diseño, montaje y caracterización. Se han realizado dos montajes de laboratorio a partir de diseños basados en modelos analíticos mostrando unas altas resoluciones espectrales y espaciales y bajas distorsiones sin el uso de redes de difracción corregidas en aberraciones ni de elementos asféricos.Palabras clave: Espectrometría de imagen, Espectrómetro Offner, Diseño óptico. REFERENCES AND LINKS / REFERENCIAS Y ENLACES[1] A. F. H. Goetz, "Three decades of hyperspectral remote sensing of the earth: A personal view," Remote Sens. Environ., 113, S5-S16 (2009).

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Spatial distribution measurement of atomic radiation with an astigmatism-corrected Czerny-Turner-type spectrometer in the Large Helical Device

Cited by 29 publications

References 8 publications

First EMC3‐EIRENE Simulations with Divertor Legs of LHD in Realistic Device Geometry

First EMC3‐EIRENE Simulations with Divertor Legs of LHD in Realistic Device Geometry

Z eff profile diagnostics using visible bremsstrahlung continuum for nonaxisymmetric plasmas with finite β in large helical device

Offner imaging spectrometers

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