2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade

L. Colas; V. Bobkov; D. Carralero; M. Kocan; Hans Werner Müller; P. Manz; M. Kubic; J. P. Gunn; A. Herrmann; V. Rohde; ASDEX Upgrade Team

doi:10.1063/1.4864537

2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade

L. Colas (Corresponding author), V. Bobkov, D. Carralero, M. Kocan, Hans Werner Müller, P. Manz, M. Kubic, J. P. Gunn, A. Herrmann, V. Rohde, ASDEX Upgrade Team

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

Abstract

Using a reciprocating Retarding Field Analyser (RFA), Scrape-Off Layer (SOL) modifications were investigated on ASDEX-Upgrade during heating with waves in the Ion Cyclotron Range of Frequencies (ICRF), suspected for enhanced impurity production in this all-metal machine. Two quantities involved in the sputtering were measured: the current I _slit on a saturated slit plate, proportional to the parallel ion flux and the mean parallel energy <W _∥> _t of collected ions, averaged over many RF cycles. Combining multiple RFA reciprocations over a scan of q ₉₅ provided 2D poloidal/radial resolution. In the outer SOL a localized RF-perturbed zone was evidenced on the RFA side magnetically connected to an active ICRF antenna. A flat 2D I _slit pattern surrounded by steep gradients was observed, correlatively with <W _∥> _t exceeding 150eV. The centre of the zone is connected radially slightly behind the leading edge of antenna side limiters, with a radial extension up to ±2cm. The zone is broadest and <W _∥> _t is largest near the bottom of the active antenna. This is interpreted as a zone of local plasma biasing via sheath rectification, creating density convection around it. The I _slit pattern is qualitatively consistent with simple considerations about E×B particle convection.

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	259-262
Number of pages	4
ISBN (Print)	9780735412101
DOIs	https://doi.org/10.1063/1.4864537
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

ICRH
RF-sheaths
sputtering
ExB convection
ASDEX-Upgrade
Retarding Field Analyser
TORE-SUPRA TOKAMAK
ALCATOR C-MOD
PLASMA
E×B convection

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10.1063/1.4864537

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Colas, L., Bobkov, V., Carralero, D., Kocan, M., Müller, H. W., Manz, P., Kubic, M., Gunn, J. P., Herrmann, A., Rohde, V., & ASDEX Upgrade Team (2014). 2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade. In AA. Tuccillo, & S. Ceccuzzi (Eds.), Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference (pp. 259-262). American Institute of Physics. https://doi.org/10.1063/1.4864537

Colas, L. ; Bobkov, V. ; Carralero, D. et al. / 2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade. Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. editor / AA Tuccillo ; S Ceccuzzi. American Institute of Physics, 2014. pp. 259-262 (AIP Conference Proceedings, Vol. 1580).

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title = "2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade",

abstract = "Using a reciprocating Retarding Field Analyser (RFA), Scrape-Off Layer (SOL) modifications were investigated on ASDEX-Upgrade during heating with waves in the Ion Cyclotron Range of Frequencies (ICRF), suspected for enhanced impurity production in this all-metal machine. Two quantities involved in the sputtering were measured: the current I slit on a saturated slit plate, proportional to the parallel ion flux and the mean parallel energy ∥> t of collected ions, averaged over many RF cycles. Combining multiple RFA reciprocations over a scan of q 95 provided 2D poloidal/radial resolution. In the outer SOL a localized RF-perturbed zone was evidenced on the RFA side magnetically connected to an active ICRF antenna. A flat 2D I slit pattern surrounded by steep gradients was observed, correlatively with ∥> t exceeding 150eV. The centre of the zone is connected radially slightly behind the leading edge of antenna side limiters, with a radial extension up to ±2cm. The zone is broadest and ∥> t is largest near the bottom of the active antenna. This is interpreted as a zone of local plasma biasing via sheath rectification, creating density convection around it. The I slit pattern is qualitatively consistent with simple considerations about E×B particle convection.",

keywords = "ICRH, RF-sheaths, sputtering, ExB convection, ASDEX-Upgrade, Retarding Field Analyser, TORE-SUPRA TOKAMAK, ALCATOR C-MOD, PLASMA, E×B convection",

author = "L. Colas and V. Bobkov and D. Carralero and M. Kocan and M{\"u}ller, \{Hans Werner\} and P. Manz and M. Kubic and Gunn, \{J. P.\} and A. Herrmann and V. Rohde and \{ASDEX Upgrade Team\}",

note = " Accession Number: WOS:000339626400042 ; 20th Topical Conference on Radio Frequency Power in Plasmas ; Conference date: 25-06-2013 Through 28-06-2013",

year = "2014",

doi = "10.1063/1.4864537",

language = "English",

isbn = "9780735412101",

series = "AIP Conference Proceedings",

publisher = "American Institute of Physics",

pages = "259--262",

editor = "AA Tuccillo and S Ceccuzzi",

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

}

Colas, L, Bobkov, V, Carralero, D, Kocan, M, Müller, HW, Manz, P, Kubic, M, Gunn, JP, Herrmann, A, Rohde, V & ASDEX Upgrade Team 2014, 2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on 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. 259-262, 20th Topical Conference on Radio Frequency Power in Plasmas, Sorrento, Italy, 25/06/13. https://doi.org/10.1063/1.4864537

2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade. / Colas, L. (Corresponding author); Bobkov, V.; Carralero, D. et al.
Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. ed. / AA Tuccillo; S Ceccuzzi. American Institute of Physics, 2014. p. 259-262 (AIP Conference Proceedings, Vol. 1580).

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

TY - GEN

T1 - 2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade

AU - Colas, L.

AU - Bobkov, V.

AU - Carralero, D.

AU - Kocan, M.

AU - Müller, Hans Werner

AU - Manz, P.

AU - Kubic, M.

AU - Gunn, J. P.

AU - Herrmann, A.

AU - Rohde, V.

AU - ASDEX Upgrade Team

N1 - Accession Number: WOS:000339626400042

PY - 2014

Y1 - 2014

N2 - Using a reciprocating Retarding Field Analyser (RFA), Scrape-Off Layer (SOL) modifications were investigated on ASDEX-Upgrade during heating with waves in the Ion Cyclotron Range of Frequencies (ICRF), suspected for enhanced impurity production in this all-metal machine. Two quantities involved in the sputtering were measured: the current I slit on a saturated slit plate, proportional to the parallel ion flux and the mean parallel energy ∥> t of collected ions, averaged over many RF cycles. Combining multiple RFA reciprocations over a scan of q 95 provided 2D poloidal/radial resolution. In the outer SOL a localized RF-perturbed zone was evidenced on the RFA side magnetically connected to an active ICRF antenna. A flat 2D I slit pattern surrounded by steep gradients was observed, correlatively with ∥> t exceeding 150eV. The centre of the zone is connected radially slightly behind the leading edge of antenna side limiters, with a radial extension up to ±2cm. The zone is broadest and ∥> t is largest near the bottom of the active antenna. This is interpreted as a zone of local plasma biasing via sheath rectification, creating density convection around it. The I slit pattern is qualitatively consistent with simple considerations about E×B particle convection.

AB - Using a reciprocating Retarding Field Analyser (RFA), Scrape-Off Layer (SOL) modifications were investigated on ASDEX-Upgrade during heating with waves in the Ion Cyclotron Range of Frequencies (ICRF), suspected for enhanced impurity production in this all-metal machine. Two quantities involved in the sputtering were measured: the current I slit on a saturated slit plate, proportional to the parallel ion flux and the mean parallel energy ∥> t of collected ions, averaged over many RF cycles. Combining multiple RFA reciprocations over a scan of q 95 provided 2D poloidal/radial resolution. In the outer SOL a localized RF-perturbed zone was evidenced on the RFA side magnetically connected to an active ICRF antenna. A flat 2D I slit pattern surrounded by steep gradients was observed, correlatively with ∥> t exceeding 150eV. The centre of the zone is connected radially slightly behind the leading edge of antenna side limiters, with a radial extension up to ±2cm. The zone is broadest and ∥> t is largest near the bottom of the active antenna. This is interpreted as a zone of local plasma biasing via sheath rectification, creating density convection around it. The I slit pattern is qualitatively consistent with simple considerations about E×B particle convection.

KW - ICRH

KW - RF-sheaths

KW - sputtering

KW - ExB convection

KW - ASDEX-Upgrade

KW - Retarding Field Analyser

KW - TORE-SUPRA TOKAMAK

KW - ALCATOR C-MOD

KW - PLASMA

KW - E×B convection

UR - https://www.scopus.com/pages/publications/84906330575

U2 - 10.1063/1.4864537

DO - 10.1063/1.4864537

M3 - Contribution to proceedings

SN - 9780735412101

T3 - AIP Conference Proceedings

SP - 259

EP - 262

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 -

Colas L, Bobkov V, Carralero D, Kocan M, Müller HW, Manz P et al. 2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade. In Tuccillo AA, Ceccuzzi S, editors, Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference. American Institute of Physics. 2014. p. 259-262. (AIP Conference Proceedings, Vol. 1580). doi: 10.1063/1.4864537

2-Dimensional Mapping of ICRF-Induced Scrape-Off Layer Modifications with a Retarding Field Analyser on ASDEX-Upgrade

Abstract

Publication series

Conference

Austrian Fields of Science 2012

Keywords

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