Progress in reducing ICRF-specific impurity release in ASDEX upgrade and JET

ASDEX Upgrade Team, the EUROfusion MST1 Team; JET Contributors

doi:10.1016/j.nme.2016.10.026

Progress in reducing ICRF-specific impurity release in ASDEX upgrade and JET

ASDEX Upgrade Team, the EUROfusion MST1 Team, JET Contributors

Fusion Engineering

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

16 Scopus citations

Abstract

Use of new 3-strap ICRF antennas with all-tungsten (W) limiters in ASDEX Upgrade results in a reduction of the W sources at the antenna limiters and of the W content in the confined plasma by at least a factor of 2 compared to the W-limiter 2-strap antennas used in the past. The reduction is observed with a broad range of plasma shapes. In multiple locations of antenna frame, the limiter W source has a minimum when RF image currents are decreased by cancellation of the RF current contributions of the central and the outer straps. In JET with ITER-like wall, ITER-like antenna produces about 20% less of main chamber radiation and of W content compared to the old A2 antennas. However the effect of the A2 antennas on W content is scattered depending on which antennas are powered. Experiments in JET with trace nitrogen (N₂) injection show that a presence of active ICRF antenna close to the midplane injection valve has little effect on the core N content, both in dipole and in -90° phasing. This indicates that the effect of ICRF on impurity transport across the scape-off-layer is small in JET compared to the dominant effect on impurity sources leading to increased impurity levels during ICRF operation.

Original language	English
Pages (from-to)	1194-1198
Number of pages	5
Journal	Nuclear Materials and Energy
Volume	12
DOIs	https://doi.org/10.1016/j.nme.2016.10.026
State	Published - Aug 2017

Funding

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053 . The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work is supported, in part, by the US DOE under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014?2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. This work is supported, in part, by the US DOE under Contract No. DE-AC05-00OR22725 with UT-Battelle, LLC.

Funders	Funder number
Euratom research and training programme 2014–2018
U.S. Department of Energy	DE-AC05-00OR22725
Horizon 2020 Framework Programme	633053
H2020 Euratom

Keywords

3-strap
A2 antenna
ASDEX Upgrade
ICRF
ILA
ILW
JET
RF sheath
Sputtering
Three-strap

UN SDGs

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

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10.1016/j.nme.2016.10.026

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@article{8f17cb7adb814e94ac96d40a62c1aaaa,

title = "Progress in reducing ICRF-specific impurity release in ASDEX upgrade and JET",

abstract = "Use of new 3-strap ICRF antennas with all-tungsten (W) limiters in ASDEX Upgrade results in a reduction of the W sources at the antenna limiters and of the W content in the confined plasma by at least a factor of 2 compared to the W-limiter 2-strap antennas used in the past. The reduction is observed with a broad range of plasma shapes. In multiple locations of antenna frame, the limiter W source has a minimum when RF image currents are decreased by cancellation of the RF current contributions of the central and the outer straps. In JET with ITER-like wall, ITER-like antenna produces about 20% less of main chamber radiation and of W content compared to the old A2 antennas. However the effect of the A2 antennas on W content is scattered depending on which antennas are powered. Experiments in JET with trace nitrogen (N2) injection show that a presence of active ICRF antenna close to the midplane injection valve has little effect on the core N content, both in dipole and in -90° phasing. This indicates that the effect of ICRF on impurity transport across the scape-off-layer is small in JET compared to the dominant effect on impurity sources leading to increased impurity levels during ICRF operation.",

keywords = "3-strap, A2 antenna, ASDEX Upgrade, ICRF, ILA, ILW, JET, RF sheath, Sputtering, Three-strap",

author = "{ASDEX Upgrade Team, the EUROfusion MST1 Team} and {JET Contributors} and V. Bobkov and D. Aguiam and M. Baruzzo and D. Borodin and I. Borodkina and S. Brezinsek and I. Coffey and L. Colas and A. Czarnecka and E. Delabie and P. Dumortier and F. Durodie and R. Dux and H. Faugel and H. F{\"u}nfgelder and C. Giroud and M. Goniche and J. Hobirk and A. Herrmann and J. Jacquot and Ph Jacquet and A. Kallenbach and A. Krivska and Klepper, {C. C.} and E. Lerche and S. Menmuir and D. Milanesio and R. Maggiora and I. Monakhov and F. Nave and R. Neu and Noterdaeme, {J. M.} and R. Ochoukov and Th P{\"u}tterich and M. Reinke and A. Tuccilo and O. Tudisco and {Van Eester}, D. and Y. Wang and Q. Yang and W. Zhang",

note = "Publisher Copyright: {\textcopyright} 2016 The Authors",

year = "2017",

month = aug,

doi = "10.1016/j.nme.2016.10.026",

language = "English",

volume = "12",

pages = "1194--1198",

journal = "Nuclear Materials and Energy",

issn = "2352-1791",

publisher = "Elsevier",

}

TY - JOUR

T1 - Progress in reducing ICRF-specific impurity release in ASDEX upgrade and JET

AU - ASDEX Upgrade Team, the EUROfusion MST1 Team

AU - JET Contributors

AU - Bobkov, V.

AU - Aguiam, D.

AU - Baruzzo, M.

AU - Borodin, D.

AU - Borodkina, I.

AU - Brezinsek, S.

AU - Coffey, I.

AU - Colas, L.

AU - Czarnecka, A.

AU - Delabie, E.

AU - Dumortier, P.

AU - Durodie, F.

AU - Dux, R.

AU - Faugel, H.

AU - Fünfgelder, H.

AU - Giroud, C.

AU - Goniche, M.

AU - Hobirk, J.

AU - Herrmann, A.

AU - Jacquot, J.

AU - Jacquet, Ph

AU - Kallenbach, A.

AU - Krivska, A.

AU - Klepper, C. C.

AU - Lerche, E.

AU - Menmuir, S.

AU - Milanesio, D.

AU - Maggiora, R.

AU - Monakhov, I.

AU - Nave, F.

AU - Neu, R.

AU - Noterdaeme, J. M.

AU - Ochoukov, R.

AU - Pütterich, Th

AU - Reinke, M.

AU - Tuccilo, A.

AU - Tudisco, O.

AU - Van Eester, D.

AU - Wang, Y.

AU - Yang, Q.

AU - Zhang, W.

PY - 2017/8

Y1 - 2017/8

N2 - Use of new 3-strap ICRF antennas with all-tungsten (W) limiters in ASDEX Upgrade results in a reduction of the W sources at the antenna limiters and of the W content in the confined plasma by at least a factor of 2 compared to the W-limiter 2-strap antennas used in the past. The reduction is observed with a broad range of plasma shapes. In multiple locations of antenna frame, the limiter W source has a minimum when RF image currents are decreased by cancellation of the RF current contributions of the central and the outer straps. In JET with ITER-like wall, ITER-like antenna produces about 20% less of main chamber radiation and of W content compared to the old A2 antennas. However the effect of the A2 antennas on W content is scattered depending on which antennas are powered. Experiments in JET with trace nitrogen (N2) injection show that a presence of active ICRF antenna close to the midplane injection valve has little effect on the core N content, both in dipole and in -90° phasing. This indicates that the effect of ICRF on impurity transport across the scape-off-layer is small in JET compared to the dominant effect on impurity sources leading to increased impurity levels during ICRF operation.

AB - Use of new 3-strap ICRF antennas with all-tungsten (W) limiters in ASDEX Upgrade results in a reduction of the W sources at the antenna limiters and of the W content in the confined plasma by at least a factor of 2 compared to the W-limiter 2-strap antennas used in the past. The reduction is observed with a broad range of plasma shapes. In multiple locations of antenna frame, the limiter W source has a minimum when RF image currents are decreased by cancellation of the RF current contributions of the central and the outer straps. In JET with ITER-like wall, ITER-like antenna produces about 20% less of main chamber radiation and of W content compared to the old A2 antennas. However the effect of the A2 antennas on W content is scattered depending on which antennas are powered. Experiments in JET with trace nitrogen (N2) injection show that a presence of active ICRF antenna close to the midplane injection valve has little effect on the core N content, both in dipole and in -90° phasing. This indicates that the effect of ICRF on impurity transport across the scape-off-layer is small in JET compared to the dominant effect on impurity sources leading to increased impurity levels during ICRF operation.

KW - 3-strap

KW - A2 antenna

KW - ASDEX Upgrade

KW - ICRF

KW - ILA

KW - ILW

KW - JET

KW - RF sheath

KW - Sputtering

KW - Three-strap

UR - http://www.scopus.com/inward/record.url?scp=85007482698&partnerID=8YFLogxK

U2 - 10.1016/j.nme.2016.10.026

DO - 10.1016/j.nme.2016.10.026

M3 - Article

AN - SCOPUS:85007482698

SN - 2352-1791

VL - 12

SP - 1194

EP - 1198

JO - Nuclear Materials and Energy

JF - Nuclear Materials and Energy

ER -

Progress in reducing ICRF-specific impurity release in ASDEX upgrade and JET

Abstract

Funding

Keywords

UN SDGs

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