Final steps to an all tungsten divertor tokamak

R. Neu; V. Bobkov; R. Dux; A. Kallenbach; Th Pütterich; H. Greuner; O. Gruber; A. Herrmann; Ch Hopf; K. Krieger; C. F. Maggi; H. Maier; M. Mayer; V. Rohde; K. Schmid; W. Suttrop

doi:10.1016/j.jnucmat.2006.12.021

Final steps to an all tungsten divertor tokamak

R. Neu, V. Bobkov, R. Dux, A. Kallenbach, Th Pütterich, H. Greuner, O. Gruber, A. Herrmann, Ch Hopf, K. Krieger, C. F. Maggi, H. Maier, M. Mayer, V. Rohde, K. Schmid, W. Suttrop

Max Planck Institute for Plasma Physics

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

92 Scopus citations

Abstract

Currently 85% of the plasma facing components of ASDEX Upgrade are tungsten coated. Carbon influx from W PFCs is still observed but a reduction of the C content is found in plasma discharges and a lower C fraction is measured in deposited layers in agreement with modelling. W sputtering from the low field side guard and ICRF limiters is mainly due to fast particles from NBI as well as from ions accelerated in the rectified sheath during ICRF operation. The increase of the W source area is reflected in increased W concentrations. For medium to high density discharges the techniques developed so far, namely central heating and ELM pace-making, allow keeping the W concentration in the range of 10^-5. Boronisation strongly reduces the W influxes and similarly the W content especially during ICRF operation, but this reduction is only temporary and equilibrium is reached already after about 100 discharges.

Original language	English
Pages (from-to)	52-59
Number of pages	8
Journal	Journal of Nuclear Materials
Volume	363-365
Issue number	1-3
DOIs	https://doi.org/10.1016/j.jnucmat.2006.12.021
State	Published - 15 Jun 2007
Externally published	Yes

Keywords

ASDEX Upgrade
C0100
Carbon impurity
D0500
F0400
Impurity source
Impurity transport
L0200
T1000
Tungsten

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10.1016/j.jnucmat.2006.12.021

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title = "Final steps to an all tungsten divertor tokamak",

abstract = "Currently 85% of the plasma facing components of ASDEX Upgrade are tungsten coated. Carbon influx from W PFCs is still observed but a reduction of the C content is found in plasma discharges and a lower C fraction is measured in deposited layers in agreement with modelling. W sputtering from the low field side guard and ICRF limiters is mainly due to fast particles from NBI as well as from ions accelerated in the rectified sheath during ICRF operation. The increase of the W source area is reflected in increased W concentrations. For medium to high density discharges the techniques developed so far, namely central heating and ELM pace-making, allow keeping the W concentration in the range of 10-5. Boronisation strongly reduces the W influxes and similarly the W content especially during ICRF operation, but this reduction is only temporary and equilibrium is reached already after about 100 discharges.",

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language = "English",

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T1 - Final steps to an all tungsten divertor tokamak

AU - Neu, R.

AU - Bobkov, V.

AU - Dux, R.

AU - Kallenbach, A.

AU - Pütterich, Th

AU - Greuner, H.

AU - Gruber, O.

AU - Herrmann, A.

AU - Hopf, Ch

AU - Krieger, K.

AU - Maggi, C. F.

AU - Maier, H.

AU - Mayer, M.

AU - Rohde, V.

AU - Schmid, K.

AU - Suttrop, W.

PY - 2007/6/15

Y1 - 2007/6/15

N2 - Currently 85% of the plasma facing components of ASDEX Upgrade are tungsten coated. Carbon influx from W PFCs is still observed but a reduction of the C content is found in plasma discharges and a lower C fraction is measured in deposited layers in agreement with modelling. W sputtering from the low field side guard and ICRF limiters is mainly due to fast particles from NBI as well as from ions accelerated in the rectified sheath during ICRF operation. The increase of the W source area is reflected in increased W concentrations. For medium to high density discharges the techniques developed so far, namely central heating and ELM pace-making, allow keeping the W concentration in the range of 10-5. Boronisation strongly reduces the W influxes and similarly the W content especially during ICRF operation, but this reduction is only temporary and equilibrium is reached already after about 100 discharges.

AB - Currently 85% of the plasma facing components of ASDEX Upgrade are tungsten coated. Carbon influx from W PFCs is still observed but a reduction of the C content is found in plasma discharges and a lower C fraction is measured in deposited layers in agreement with modelling. W sputtering from the low field side guard and ICRF limiters is mainly due to fast particles from NBI as well as from ions accelerated in the rectified sheath during ICRF operation. The increase of the W source area is reflected in increased W concentrations. For medium to high density discharges the techniques developed so far, namely central heating and ELM pace-making, allow keeping the W concentration in the range of 10-5. Boronisation strongly reduces the W influxes and similarly the W content especially during ICRF operation, but this reduction is only temporary and equilibrium is reached already after about 100 discharges.

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KW - C0100

KW - Carbon impurity

KW - D0500

KW - F0400

KW - Impurity source

KW - Impurity transport

KW - L0200

KW - T1000

KW - Tungsten

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JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

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ER -

Final steps to an all tungsten divertor tokamak

Abstract

Keywords

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