Divertor detachment during pure helium plasmas in JET

M. Wischmeier; D. Coster; X. Bonnin; T. Eich; A. Huber; C. Ingesson; S. Jachmich; A. Kukushkin; A. Loarte; G. F. Matthews; R. A. Pitts; J. Rapp; D. Reiter; E. Tsitrone

doi:10.1016/S0022-3115(02)01427-7

Divertor detachment during pure helium plasmas in JET

M. Wischmeier, D. Coster, X. Bonnin, T. Eich, A. Huber, C. Ingesson, S. Jachmich, A. Kukushkin, A. Loarte, G. F. Matthews, R. A. Pitts, J. Rapp, D. Reiter, E. Tsitrone

Research output: Contribution to journal › Conference article › peer-review

16 Scopus citations

Abstract

A campaign of pure helium discharges in the JET tokamak equipped with the MarkIIGB divertor has been performed. This paper describes some of the experimental observations of divertor detachment obtained in L-mode density ramp He discharges and presents a selection of results from the application of B2.5-Eirene code modelling to a JET He plasma. Detachment is very different from that observed in equivalent D discharges. Particle fluxes remain attached up to higher densities and, with decreasing input power, particle detachment occurs earlier in density. However, in contrast to comparable D plasmas, the low measured target T_e at all but the lowest n_e in helium leads to an earlier decrease in power flux. Simulations show that detachment is caused by the escape of He neutrals from the target vicinity where, together with the He⁺ ions they radiate along the separatrix and above the X-point area, starving regions downstream of power.

Original language	English
Pages (from-to)	980-985
Number of pages	6
Journal	Journal of Nuclear Materials
Volume	313-316
Issue number	SUPPL.
DOIs	https://doi.org/10.1016/S0022-3115(02)01427-7
State	Published - Mar 2003
Externally published	Yes
Event	Plasma - Surface Interactions in Controlled Fusion Devices - Gifu, Japan Duration: May 26 2002 → May 31 2002

Funding

This work was performed under the European Fusion Development Agreement and was supported in part by the Swiss National Science Foundation, EURATOM and the UK Department of Trade and Industry.

Keywords

B2.5-Eirene
Detachment
Divertor
Helium
JET
Tokamak

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/S0022-3115(02)01427-7

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title = "Divertor detachment during pure helium plasmas in JET",

abstract = "A campaign of pure helium discharges in the JET tokamak equipped with the MarkIIGB divertor has been performed. This paper describes some of the experimental observations of divertor detachment obtained in L-mode density ramp He discharges and presents a selection of results from the application of B2.5-Eirene code modelling to a JET He plasma. Detachment is very different from that observed in equivalent D discharges. Particle fluxes remain attached up to higher densities and, with decreasing input power, particle detachment occurs earlier in density. However, in contrast to comparable D plasmas, the low measured target Te at all but the lowest ne in helium leads to an earlier decrease in power flux. Simulations show that detachment is caused by the escape of He neutrals from the target vicinity where, together with the He+ ions they radiate along the separatrix and above the X-point area, starving regions downstream of power.",

keywords = "B2.5-Eirene, Detachment, Divertor, Helium, JET, Tokamak",

author = "M. Wischmeier and D. Coster and X. Bonnin and T. Eich and A. Huber and C. Ingesson and S. Jachmich and A. Kukushkin and A. Loarte and Matthews, {G. F.} and Pitts, {R. A.} and J. Rapp and D. Reiter and E. Tsitrone",

year = "2003",

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doi = "10.1016/S0022-3115(02)01427-7",

language = "English",

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journal = "Journal of Nuclear Materials",

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TY - JOUR

T1 - Divertor detachment during pure helium plasmas in JET

AU - Wischmeier, M.

AU - Coster, D.

AU - Bonnin, X.

AU - Eich, T.

AU - Huber, A.

AU - Ingesson, C.

AU - Jachmich, S.

AU - Kukushkin, A.

AU - Loarte, A.

AU - Matthews, G. F.

AU - Pitts, R. A.

AU - Rapp, J.

AU - Reiter, D.

AU - Tsitrone, E.

PY - 2003/3

Y1 - 2003/3

N2 - A campaign of pure helium discharges in the JET tokamak equipped with the MarkIIGB divertor has been performed. This paper describes some of the experimental observations of divertor detachment obtained in L-mode density ramp He discharges and presents a selection of results from the application of B2.5-Eirene code modelling to a JET He plasma. Detachment is very different from that observed in equivalent D discharges. Particle fluxes remain attached up to higher densities and, with decreasing input power, particle detachment occurs earlier in density. However, in contrast to comparable D plasmas, the low measured target Te at all but the lowest ne in helium leads to an earlier decrease in power flux. Simulations show that detachment is caused by the escape of He neutrals from the target vicinity where, together with the He+ ions they radiate along the separatrix and above the X-point area, starving regions downstream of power.

AB - A campaign of pure helium discharges in the JET tokamak equipped with the MarkIIGB divertor has been performed. This paper describes some of the experimental observations of divertor detachment obtained in L-mode density ramp He discharges and presents a selection of results from the application of B2.5-Eirene code modelling to a JET He plasma. Detachment is very different from that observed in equivalent D discharges. Particle fluxes remain attached up to higher densities and, with decreasing input power, particle detachment occurs earlier in density. However, in contrast to comparable D plasmas, the low measured target Te at all but the lowest ne in helium leads to an earlier decrease in power flux. Simulations show that detachment is caused by the escape of He neutrals from the target vicinity where, together with the He+ ions they radiate along the separatrix and above the X-point area, starving regions downstream of power.

KW - B2.5-Eirene

KW - Detachment

KW - Divertor

KW - Helium

KW - JET

KW - Tokamak

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U2 - 10.1016/S0022-3115(02)01427-7

DO - 10.1016/S0022-3115(02)01427-7

M3 - Conference article

AN - SCOPUS:17444442855

SN - 0022-3115

VL - 313-316

SP - 980

EP - 985

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

IS - SUPPL.

T2 - Plasma - Surface Interactions in Controlled Fusion Devices

Y2 - 26 May 2002 through 31 May 2002

ER -

Divertor detachment during pure helium plasmas in JET

Abstract

Funding

Keywords

UN SDGs

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