Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD

LHD Experiment Group; B.J. Peterson; G. Kawamura; Peter van de Giessen; K. Mukai; H. Tanaka; R. Sano; S.N. Pandya; S.Y. Dai; S. Masuzaki; T. Akiyama; M. Kobayashi; M. Gota; G. Motojima; R. Sakomoto; N. Ohno; T. Morisaki; J. Miyazawa

doi:10.1016/j.nme.2020.100848

Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD

LHD Experiment Group, B.J. Peterson (Corresponding author), G. Kawamura, Peter van de Giessen, K. Mukai, H. Tanaka, R. Sano, S.N. Pandya, S.Y. Dai, S. Masuzaki, T. Akiyama, M. Kobayashi, M. Gota, G. Motojima, R. Sakomoto, N. Ohno, T. Morisaki, J. Miyazawa

Science and Technology of Nuclear Fusion

Research output: Contribution to journal › Article › Academic › peer-review

8 Citations (Scopus)

Abstract

N2 gas has been seeded in the Large Helical Device (LHD) to reduce the divertor heat load through enhanced radiation. Radiation is observed by two imaging bolometers, viewing the same poloidal cross-section from top and bottom ports, at a location which is 36°toroidally removed from the N2 gas puff nozzle located at the bottom of the machine. During N2 seeding, these measurements both confirm that additional radiation from the outboard side is coming exclusively from the top of the cross-section, indicating up/down asymmetry, which is also reproduced by modelling with EMC3-EIRENE using a half torus model. In addition, a toroidally localized, magnetic field direction-dependent radiation enhancement is observed with N2 seeding, but is not reproducible by the model.

Original language	English
Article number	100848
Pages (from-to)	1-8
Number of pages	8
Journal	Nuclear Materials and Energy
Volume	26
DOIs	https://doi.org/10.1016/j.nme.2020.100848
Publication status	Published - 1 Mar 2021

Keywords

Bolometer
Impurity seeding
Magnetic fusion
Plasma
Radiation

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LHD Experiment Group, Peterson, B. J., Kawamura, G., van de Giessen, P., Mukai, K., Tanaka, H., Sano, R., Pandya, S. N., Dai, S. Y., Masuzaki, S., Akiyama, T., Kobayashi, M., Gota, M., Motojima, G., Sakomoto, R., Ohno, N., Morisaki, T., & Miyazawa, J. (2021). Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD. Nuclear Materials and Energy, 26, 1-8. Article 100848. https://doi.org/10.1016/j.nme.2020.100848

@article{1b5ee425b1a1447dadd9a1ff18586e58,

title = "Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD",

abstract = "N2 gas has been seeded in the Large Helical Device (LHD) to reduce the divertor heat load through enhanced radiation. Radiation is observed by two imaging bolometers, viewing the same poloidal cross-section from top and bottom ports, at a location which is 36°toroidally removed from the N2 gas puff nozzle located at the bottom of the machine. During N2 seeding, these measurements both confirm that additional radiation from the outboard side is coming exclusively from the top of the cross-section, indicating up/down asymmetry, which is also reproduced by modelling with EMC3-EIRENE using a half torus model. In addition, a toroidally localized, magnetic field direction-dependent radiation enhancement is observed with N2 seeding, but is not reproducible by the model.",

keywords = "Bolometer, Impurity seeding, Magnetic fusion, Plasma, Radiation",

author = "{LHD Experiment Group} and B.J. Peterson and G. Kawamura and {van de Giessen}, Peter and K. Mukai and H. Tanaka and R. Sano and S.N. Pandya and S.Y. Dai and S. Masuzaki and T. Akiyama and M. Kobayashi and M. Gota and G. Motojima and R. Sakomoto and N. Ohno and T. Morisaki and J. Miyazawa",

year = "2021",

month = mar,

day = "1",

doi = "10.1016/j.nme.2020.100848",

language = "English",

volume = "26",

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journal = "Nuclear Materials and Energy",

issn = "2352-1791",

publisher = "Elsevier",

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LHD Experiment Group, Peterson, BJ, Kawamura, G, van de Giessen, P, Mukai, K, Tanaka, H, Sano, R, Pandya, SN, Dai, SY, Masuzaki, S, Akiyama, T, Kobayashi, M, Gota, M, Motojima, G, Sakomoto, R, Ohno, N, Morisaki, T & Miyazawa, J 2021, 'Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD', Nuclear Materials and Energy, vol. 26, 100848, pp. 1-8. https://doi.org/10.1016/j.nme.2020.100848

TY - JOUR

T1 - Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD

AU - LHD Experiment Group

AU - Peterson, B.J.

AU - Kawamura, G.

AU - van de Giessen, Peter

AU - Mukai, K.

AU - Tanaka, H.

AU - Sano, R.

AU - Pandya, S.N.

AU - Dai, S.Y.

AU - Masuzaki, S.

AU - Akiyama, T.

AU - Kobayashi, M.

AU - Gota, M.

AU - Motojima, G.

AU - Sakomoto, R.

AU - Ohno, N.

AU - Morisaki, T.

AU - Miyazawa, J.

PY - 2021/3/1

Y1 - 2021/3/1

N2 - N2 gas has been seeded in the Large Helical Device (LHD) to reduce the divertor heat load through enhanced radiation. Radiation is observed by two imaging bolometers, viewing the same poloidal cross-section from top and bottom ports, at a location which is 36°toroidally removed from the N2 gas puff nozzle located at the bottom of the machine. During N2 seeding, these measurements both confirm that additional radiation from the outboard side is coming exclusively from the top of the cross-section, indicating up/down asymmetry, which is also reproduced by modelling with EMC3-EIRENE using a half torus model. In addition, a toroidally localized, magnetic field direction-dependent radiation enhancement is observed with N2 seeding, but is not reproducible by the model.

AB - N2 gas has been seeded in the Large Helical Device (LHD) to reduce the divertor heat load through enhanced radiation. Radiation is observed by two imaging bolometers, viewing the same poloidal cross-section from top and bottom ports, at a location which is 36°toroidally removed from the N2 gas puff nozzle located at the bottom of the machine. During N2 seeding, these measurements both confirm that additional radiation from the outboard side is coming exclusively from the top of the cross-section, indicating up/down asymmetry, which is also reproduced by modelling with EMC3-EIRENE using a half torus model. In addition, a toroidally localized, magnetic field direction-dependent radiation enhancement is observed with N2 seeding, but is not reproducible by the model.

KW - Bolometer

KW - Impurity seeding

KW - Magnetic fusion

KW - Plasma

KW - Radiation

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U2 - 10.1016/j.nme.2020.100848

DO - 10.1016/j.nme.2020.100848

M3 - Article

SN - 2352-1791

VL - 26

SP - 1

EP - 8

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

M1 - 100848

ER -

Experimental observations and modelling of radiation asymmetries during N2 seeding in LHD

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Keywords

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