Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade

V. Bobkov; I. Stepanov; P. Jacquet; I. Monakhov; R. Bilato; L. Colas; A. Czarnecka; R. Dux; H. Faugel; A. Kallenbach; Hans Werner Müller; J. -M. Noterdaeme; S. Potzel; Th. Puetterich; W. Suttrop; ASDEX Upgrade Team

doi:10.1063/1.4864540

Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade

V. Bobkov (Corresponding author), I. Stepanov, P. Jacquet, I. Monakhov, R. Bilato, L. Colas, A. Czarnecka, R. Dux, H. Faugel, A. Kallenbach, Hans Werner Müller, J. -M. Noterdaeme, S. Potzel, Th. Puetterich, W. Suttrop, ASDEX Upgrade Team

Publications: Contribution to book › Contribution to proceedings › Peer Reviewed

Abstract

In ASDEX Upgrade H-modes with H ₉₈≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The antenna loading resistance R _a between and during ELMs can increase by more than 25% after a switch-over from a deuterium rate of 7.5·10 ²¹ D/s injected from a toroidally remote location to the same amount of deuterium injected close to an antenna. However, in contrast to L-mode, this effect is small in H-mode when the valve downstream w.r.t. parallel plasma flows is used. In L-mode, a non-linearity of R _a at P _ICRP<30 kW is observed when using the gas valve integrated in antenna. Application of magnetic perturbations (MPs) in H-mode discharges leads to an increase of R _a>30% with no effect of spectrum and phase of MPs on R _a found so far. In the case ELMs are fully mitigated, the antenna loading is higher and steadier. In the case ELMs are not fully mitigated, the value of R _a between ELMs is increased. Looking at the W source modification for the improved loading, the local gas injection is accompanied by decreased values of tungsten (W) influx Γ _W from the limiters and its effective sputtering yield Y _w, with the exception of the locations directly at the antenna gas valve. Application of MPs leads to increase of Γ _W and Y _w for some of the MP phases. With nitrogen seeding in the divertor, ICRF is routinely used to avoid impurity accumulation and that despite enhanced Γ _W and Y _W at the antenna limiters.

Original language	English
Title of host publication	Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference
Editors	AA Tuccillo, S Ceccuzzi
Publisher	American Institute of Physics
Pages	271-274
Number of pages	4
ISBN (Print)	9780735412101
DOIs	https://doi.org/10.1063/1.4864540
Publication status	Published - 2014
Externally published	Yes
Event	20th Topical Conference on Radio Frequency Power in Plasmas - Sorrento, Italy Duration: 25 Jun 2013 → 28 Jun 2013

Publication series

Series	AIP Conference Proceedings
Volume	1580
ISSN	0094-243X

Conference

Conference	20th Topical Conference on Radio Frequency Power in Plasmas
Country/Territory	Italy
City	Sorrento
Period	25/06/13 → 28/06/13

Austrian Fields of Science 2012

103022 Plasma physics

Keywords

ASDEX Upgrade
ICRF
antenna
coupling
sputtering
SCRAPE-OFF LAYER

Access to Document

10.1063/1.4864540

Cite this

Bobkov, V., Stepanov, I., Jacquet, P., Monakhov, I., Bilato, R., Colas, L., Czarnecka, A., Dux, R., Faugel, H., Kallenbach, A., Müller, H. W., Noterdaeme, J. .-M., Potzel, S., Puetterich, T., Suttrop, W., & ASDEX Upgrade Team (2014). Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade. In AA. Tuccillo, & S. Ceccuzzi (Eds.), Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference (pp. 271-274). American Institute of Physics. https://doi.org/10.1063/1.4864540

@inproceedings{221a83f5e64a4a84a0ba63ba109afcf4,

title = "Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade",

abstract = "In ASDEX Upgrade H-modes with H 98≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The antenna loading resistance R a between and during ELMs can increase by more than 25\% after a switch-over from a deuterium rate of 7.5·10 21 D/s injected from a toroidally remote location to the same amount of deuterium injected close to an antenna. However, in contrast to L-mode, this effect is small in H-mode when the valve downstream w.r.t. parallel plasma flows is used. In L-mode, a non-linearity of R a at P ICRP<30 kW is observed when using the gas valve integrated in antenna. Application of magnetic perturbations (MPs) in H-mode discharges leads to an increase of R a>30\% with no effect of spectrum and phase of MPs on R a found so far. In the case ELMs are fully mitigated, the antenna loading is higher and steadier. In the case ELMs are not fully mitigated, the value of R a between ELMs is increased. Looking at the W source modification for the improved loading, the local gas injection is accompanied by decreased values of tungsten (W) influx Γ W from the limiters and its effective sputtering yield Y w, with the exception of the locations directly at the antenna gas valve. Application of MPs leads to increase of Γ W and Y w for some of the MP phases. With nitrogen seeding in the divertor, ICRF is routinely used to avoid impurity accumulation and that despite enhanced Γ W and Y W at the antenna limiters.",

keywords = "ASDEX Upgrade, ICRF, antenna, coupling, sputtering, SCRAPE-OFF LAYER",

author = "V. Bobkov and I. Stepanov and P. Jacquet and I. Monakhov and R. Bilato and L. Colas and A. Czarnecka and R. Dux and H. Faugel and A. Kallenbach and M{\"u}ller, \{Hans Werner\} and Noterdaeme, \{J. -M.\} and S. Potzel and Th. Puetterich and W. Suttrop and \{ASDEX Upgrade Team\}",

note = " Accession Number: WOS:000339626400045 ; 20th Topical Conference on Radio Frequency Power in Plasmas ; Conference date: 25-06-2013 Through 28-06-2013",

year = "2014",

doi = "10.1063/1.4864540",

language = "English",

isbn = "9780735412101",

series = "AIP Conference Proceedings",

publisher = "American Institute of Physics",

pages = "271--274",

editor = "AA Tuccillo and S Ceccuzzi",

booktitle = "Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference",

}

Bobkov, V, Stepanov, I, Jacquet, P, Monakhov, I, Bilato, R, Colas, L, Czarnecka, A, Dux, R, Faugel, H, Kallenbach, A, Müller, HW, Noterdaeme, J-M, Potzel, S, Puetterich, T, Suttrop, W & ASDEX Upgrade Team 2014, Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade. in AA Tuccillo & S Ceccuzzi (eds), Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. American Institute of Physics, AIP Conference Proceedings, vol. 1580, pp. 271-274, 20th Topical Conference on Radio Frequency Power in Plasmas, Sorrento, Italy, 25/06/13. https://doi.org/10.1063/1.4864540

Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade. / Bobkov, V. (Corresponding author); Stepanov, I.; Jacquet, P. et al.
Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. ed. / AA Tuccillo; S Ceccuzzi. American Institute of Physics, 2014. p. 271-274 (AIP Conference Proceedings, Vol. 1580).

Publications: Contribution to book › Contribution to proceedings › Peer Reviewed

TY - GEN

T1 - Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade

AU - Bobkov, V.

AU - Stepanov, I.

AU - Jacquet, P.

AU - Monakhov, I.

AU - Bilato, R.

AU - Colas, L.

AU - Czarnecka, A.

AU - Dux, R.

AU - Faugel, H.

AU - Kallenbach, A.

AU - Müller, Hans Werner

AU - Noterdaeme, J. -M.

AU - Potzel, S.

AU - Puetterich, Th.

AU - Suttrop, W.

AU - ASDEX Upgrade Team

N1 - Accession Number: WOS:000339626400045

PY - 2014

Y1 - 2014

N2 - In ASDEX Upgrade H-modes with H 98≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The antenna loading resistance R a between and during ELMs can increase by more than 25% after a switch-over from a deuterium rate of 7.5·10 21 D/s injected from a toroidally remote location to the same amount of deuterium injected close to an antenna. However, in contrast to L-mode, this effect is small in H-mode when the valve downstream w.r.t. parallel plasma flows is used. In L-mode, a non-linearity of R a at P ICRP<30 kW is observed when using the gas valve integrated in antenna. Application of magnetic perturbations (MPs) in H-mode discharges leads to an increase of R a>30% with no effect of spectrum and phase of MPs on R a found so far. In the case ELMs are fully mitigated, the antenna loading is higher and steadier. In the case ELMs are not fully mitigated, the value of R a between ELMs is increased. Looking at the W source modification for the improved loading, the local gas injection is accompanied by decreased values of tungsten (W) influx Γ W from the limiters and its effective sputtering yield Y w, with the exception of the locations directly at the antenna gas valve. Application of MPs leads to increase of Γ W and Y w for some of the MP phases. With nitrogen seeding in the divertor, ICRF is routinely used to avoid impurity accumulation and that despite enhanced Γ W and Y W at the antenna limiters.

AB - In ASDEX Upgrade H-modes with H 98≈0.95, similar effect of the ICRF antenna loading improvement by local gas injection was observed as previously in L-modes. The antenna loading resistance R a between and during ELMs can increase by more than 25% after a switch-over from a deuterium rate of 7.5·10 21 D/s injected from a toroidally remote location to the same amount of deuterium injected close to an antenna. However, in contrast to L-mode, this effect is small in H-mode when the valve downstream w.r.t. parallel plasma flows is used. In L-mode, a non-linearity of R a at P ICRP<30 kW is observed when using the gas valve integrated in antenna. Application of magnetic perturbations (MPs) in H-mode discharges leads to an increase of R a>30% with no effect of spectrum and phase of MPs on R a found so far. In the case ELMs are fully mitigated, the antenna loading is higher and steadier. In the case ELMs are not fully mitigated, the value of R a between ELMs is increased. Looking at the W source modification for the improved loading, the local gas injection is accompanied by decreased values of tungsten (W) influx Γ W from the limiters and its effective sputtering yield Y w, with the exception of the locations directly at the antenna gas valve. Application of MPs leads to increase of Γ W and Y w for some of the MP phases. With nitrogen seeding in the divertor, ICRF is routinely used to avoid impurity accumulation and that despite enhanced Γ W and Y W at the antenna limiters.

KW - ASDEX Upgrade

KW - ICRF

KW - antenna

KW - coupling

KW - sputtering

KW - SCRAPE-OFF LAYER

UR - https://www.scopus.com/pages/publications/84906351102

U2 - 10.1063/1.4864540

DO - 10.1063/1.4864540

M3 - Contribution to proceedings

SN - 9780735412101

T3 - AIP Conference Proceedings

SP - 271

EP - 274

BT - Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference

A2 - Tuccillo, AA

A2 - Ceccuzzi, S

PB - American Institute of Physics

T2 - 20th Topical Conference on Radio Frequency Power in Plasmas

Y2 - 25 June 2013 through 28 June 2013

ER -

Bobkov V, Stepanov I, Jacquet P, Monakhov I, Bilato R, Colas L et al. Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade. In Tuccillo AA, Ceccuzzi S, editors, Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. American Institute of Physics. 2014. p. 271-274. (AIP Conference Proceedings, Vol. 1580). doi: 10.1063/1.4864540

Influence of Gas Injection Location and Magnetic Perturbations on ICRF Antenna Performance in ASDEX Upgrade

Abstract

Publication series

Conference

Austrian Fields of Science 2012

Keywords

Access to Document

Other files and links

Fingerprint

Cite this