Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak

T. Happel; M. L. Reinke; D. Silvagni; M. Bernert; O. Grover; P. Hennequin; A. E. Hubbard; U. Plank; E. Trier; D. Brida; P. David; R. Fischer; L. Gil; K. Höfler; P. Manz; R. M. McDermott; A. Merle; U. Stroth; E. Viezzer; M. Willensdorfer

doi:10.1088/1741-4326/abd7b7

Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak

T. Happel, M. L. Reinke, D. Silvagni, M. Bernert, O. Grover, P. Hennequin, A. E. Hubbard, U. Plank, E. Trier, D. Brida, P. David, R. Fischer, L. Gil, K. Höfler, P. Manz, R. M. McDermott, A. Merle, U. Stroth, E. Viezzer, M. Willensdorfer

Chair of Plasmarand- und Divertorphysik

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8 Scopus citations

Abstract

Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) are reported from the ASDEX Upgrade tokamak. When nitrogen is introduced into the divertor and radiation losses cool the divertor plasma down, a loss of core confinement is observed, concomitant with an increase in low frequency edge fluctuation levels. The loss in confinement can be compensated and the I-mode can be maintained by additional heating power input. Detachment of the inner divertor leg has been observed for the first time in an I-mode discharge. The outer divertor leg remains attached in these experiments. Good energy confinement properties (H 98(y, 2) = 0.9) during the detachment of the inner divertor leg are reported.

Original language	English
Article number	036026
Journal	Nuclear Fusion
Volume	61
Issue number	3
DOIs	https://doi.org/10.1088/1741-4326/abd7b7
State	Published - Mar 2021

Keywords

ELM-free
I-mode
confinement regime
detachment
nitrogen seeding
tokamak

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10.1088/1741-4326/abd7b7

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Happel, T., Reinke, M. L., Silvagni, D., Bernert, M., Grover, O., Hennequin, P., Hubbard, A. E., Plank, U., Trier, E., Brida, D., David, P., Fischer, R., Gil, L., Höfler, K., Manz, P., McDermott, R. M., Merle, A., Stroth, U., Viezzer, E., & Willensdorfer, M. (2021). Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak. Nuclear Fusion, 61(3), Article 036026. https://doi.org/10.1088/1741-4326/abd7b7

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title = "Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak",

abstract = "Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) are reported from the ASDEX Upgrade tokamak. When nitrogen is introduced into the divertor and radiation losses cool the divertor plasma down, a loss of core confinement is observed, concomitant with an increase in low frequency edge fluctuation levels. The loss in confinement can be compensated and the I-mode can be maintained by additional heating power input. Detachment of the inner divertor leg has been observed for the first time in an I-mode discharge. The outer divertor leg remains attached in these experiments. Good energy confinement properties (H 98(y, 2) = 0.9) during the detachment of the inner divertor leg are reported.",

keywords = "ELM-free, I-mode, confinement regime, detachment, nitrogen seeding, tokamak",

author = "T. Happel and Reinke, {M. L.} and D. Silvagni and M. Bernert and O. Grover and P. Hennequin and Hubbard, {A. E.} and U. Plank and E. Trier and D. Brida and P. David and R. Fischer and L. Gil and K. H{\"o}fler and P. Manz and McDermott, {R. M.} and A. Merle and U. Stroth and E. Viezzer and M. Willensdorfer",

note = "Publisher Copyright: {\textcopyright} EURATOM 2021.",

year = "2021",

month = mar,

doi = "10.1088/1741-4326/abd7b7",

language = "English",

volume = "61",

journal = "Nuclear Fusion",

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number = "3",

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Happel, T, Reinke, ML, Silvagni, D, Bernert, M, Grover, O, Hennequin, P, Hubbard, AE, Plank, U, Trier, E, Brida, D, David, P, Fischer, R, Gil, L, Höfler, K, Manz, P, McDermott, RM, Merle, A, Stroth, U, Viezzer, E & Willensdorfer, M 2021, 'Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak', Nuclear Fusion, vol. 61, no. 3, 036026. https://doi.org/10.1088/1741-4326/abd7b7

TY - JOUR

T1 - Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak

AU - Happel, T.

AU - Reinke, M. L.

AU - Silvagni, D.

AU - Bernert, M.

AU - Grover, O.

AU - Hennequin, P.

AU - Hubbard, A. E.

AU - Plank, U.

AU - Trier, E.

AU - Brida, D.

AU - David, P.

AU - Fischer, R.

AU - Gil, L.

AU - Höfler, K.

AU - Manz, P.

AU - McDermott, R. M.

AU - Merle, A.

AU - Stroth, U.

AU - Viezzer, E.

AU - Willensdorfer, M.

PY - 2021/3

Y1 - 2021/3

N2 - Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) are reported from the ASDEX Upgrade tokamak. When nitrogen is introduced into the divertor and radiation losses cool the divertor plasma down, a loss of core confinement is observed, concomitant with an increase in low frequency edge fluctuation levels. The loss in confinement can be compensated and the I-mode can be maintained by additional heating power input. Detachment of the inner divertor leg has been observed for the first time in an I-mode discharge. The outer divertor leg remains attached in these experiments. Good energy confinement properties (H 98(y, 2) = 0.9) during the detachment of the inner divertor leg are reported.

AB - Experiments on nitrogen assisted divertor detachment in the improved energy confinement mode (I-mode) are reported from the ASDEX Upgrade tokamak. When nitrogen is introduced into the divertor and radiation losses cool the divertor plasma down, a loss of core confinement is observed, concomitant with an increase in low frequency edge fluctuation levels. The loss in confinement can be compensated and the I-mode can be maintained by additional heating power input. Detachment of the inner divertor leg has been observed for the first time in an I-mode discharge. The outer divertor leg remains attached in these experiments. Good energy confinement properties (H 98(y, 2) = 0.9) during the detachment of the inner divertor leg are reported.

KW - ELM-free

KW - I-mode

KW - confinement regime

KW - detachment

KW - nitrogen seeding

KW - tokamak

UR - http://www.scopus.com/inward/record.url?scp=85102195420&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/abd7b7

DO - 10.1088/1741-4326/abd7b7

M3 - Article

AN - SCOPUS:85102195420

SN - 0029-5515

VL - 61

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 3

M1 - 036026

ER -

Approaching detachment in I-mode - Response of core confinement and the edge pedestal in the ASDEX Upgrade tokamak

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Keywords

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