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

Journal Article · Wed Nov 30 00:00:00 EST 2016 · Nuclear Materials and Energy

DOI:https://doi.org/10.1016/j.nme.2016.10.026· OSTI ID:1648924

Bobkov, V. ^[1]; Aguiam, D. ^[2]; Baruzzo, M. ^[3]; Borodin, D. ^[4]; Borodkina, I. ^[5]; Brezinsek, S. ^[4]; Coffey, I. ^[6]; Colas, L. ^[7]; Czarnecka, A. ^[8]; Delabie, E.  ^[9]; Dumortier, P. ^[10]; Durodie, F. ^[10]; Dux, R. ^[1]; Faugel, H. ^[1]; Fünfgelder, H. ^[1]; Giroud, C. ^[6]; Goniche, M. ^[7]; Hobirk, J. ^[1]; Herrmann, A. ^[1]; Jacquot, J. ^[1] ; Jacquet, Ph ^[6]; Kallenbach, A. ^[1]; Krivska, A. ^[10]; Klepper, C. C.  ^[9]; Lerche, E. ^[10]; Menmuir, S. ^[6]; Milanesio, D.  ^[11]; Maggiora, R. ^[11]; Monakhov, I. ^[6]; Nave, F. ^[2]; Neu, R.  ^[12]; Noterdaeme, J.-M. ^[13]; Ochoukov, R. ^[1]; Pütterich, Th ^[1]; Reinke, M.  ^[9]; Tuccilo, A. ^[3]; Tudisco, O. ^[3]; Van Eester, D. ^[10]; Wang, Y. ^[14]; Yang, Q. ^[14]; Zhang, W. ^[13]

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1. Max-Planck-Inst. für Plasmaphysik, Garching (Germany)
2. Univ. de Lisboa (Portugal). Inst. de Plasmas e Fusão Nuclear, Inst. Superior Técnico,
3. ENEA, Frascati (Italy)
4. Forschungszentrum Juelich (Germany). Inst. fur Energie- und Klimaforschung (IEK)
5. Forschungszentrum Juelich (Germany). Inst. fur Energie- und Klimaforschung (IEK); National Research Nuclear Univ. (Mephi). Moscow (Russia)
6. Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE)
7. Commissariat a l'Energie Atomique (CEA), Saint-Paul-Lez-Durance (France). IRFM
8. Inst. of Plasma Physics and Laser Microfusion Warsaw (Poland)
9. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
10. LPP-ERM-KMS, Brussels (Belgium)
11. Politecnico de Torino (Italy)
12. Max-Planck-Inst. für Plasmaphysik, Garching (Germany); Technische Univ. Munchen, Garching (Germany)
13. Max-Planck-Inst. für Plasmaphysik, Garching (Germany); Univ. of Ghent (Belgium). Applied Physics Dept.
14. Chinese Academy of Sciences (CAS), Hefei (China). ASIPP, Inst. of Plasma Physics

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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE; Euratom
• Grant/Contract Number: AC05-00OR22725; 633053
• OSTI ID: 1648924
• Journal Information: Nuclear Materials and Energy, Vol. 12; ISSN 2352-1791
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
1CRF
RF sheath
three-strap
3-strap
ASDEX upgrade
JET
ILW
A2 antenna
1LA
sputtering