Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

Vl V. Bobkov; F. Braun; D. A. Hartmann; P. Lamalle; I. Monakhov; J. M. Noterdaeme; E. Würsching

doi:10.1016/j.jnucmat.2004.10.109

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

Vl V. Bobkov, F. Braun, D. A. Hartmann, P. Lamalle, I. Monakhov, J. M. Noterdaeme, E. Würsching

Laboratory for Plasma Physics

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

Abstract

The coupling characteristics of the ion cyclotron range of frequencies antenna during type I edge localized modes (ELMs), asymmetries in the reaction of toroidally distributed antennas to ELMs and arcing phenomena following ELMs are studied for ASDEX Upgrade. The maximum change of the antenna resistance due to ELMs increases with triangularity δ_L in the on-axis minority heating. In the cases with off-axis heating, the change of the resistance is less sensitive to δ_L. Time-resolved RF measurements show asymmetries in times of response of the toroidally distributed antennas to the rising edge of ELMs and in the further evolution of this response. Toroidal propagation of ELM perturbations in counter-current direction with times ≈₅₀ μs for one toroidal turn is observed. ELM-induced arcing is observed during ELMs and with delays after ELMs. Conditioning takes place as the arc number during ELMs decreases and time delay between ELM and arc increases.

Original language	English
Pages (from-to)	776-780
Number of pages	5
Journal	Journal of Nuclear Materials
Volume	337-339
Issue number	1-3 SPEC. ISS.
DOIs	https://doi.org/10.1016/j.jnucmat.2004.10.109
Publication status	Published - 1 Mar 2005

Keywords

ASDEX Upgrade
ELM
ICRF antenna
RF discharge

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10.1016/j.jnucmat.2004.10.109

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title = "Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade",

abstract = "The coupling characteristics of the ion cyclotron range of frequencies antenna during type I edge localized modes (ELMs), asymmetries in the reaction of toroidally distributed antennas to ELMs and arcing phenomena following ELMs are studied for ASDEX Upgrade. The maximum change of the antenna resistance due to ELMs increases with triangularity δL in the on-axis minority heating. In the cases with off-axis heating, the change of the resistance is less sensitive to δL. Time-resolved RF measurements show asymmetries in times of response of the toroidally distributed antennas to the rising edge of ELMs and in the further evolution of this response. Toroidal propagation of ELM perturbations in counter-current direction with times ≈50 μs for one toroidal turn is observed. ELM-induced arcing is observed during ELMs and with delays after ELMs. Conditioning takes place as the arc number during ELMs decreases and time delay between ELM and arc increases.",

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author = "Bobkov, \{Vl V.\} and F. Braun and Hartmann, \{D. A.\} and P. Lamalle and I. Monakhov and Noterdaeme, \{J. M.\} and E. W{\"u}rsching",

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T1 - Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

AU - Bobkov, Vl V.

AU - Braun, F.

AU - Hartmann, D. A.

AU - Lamalle, P.

AU - Monakhov, I.

AU - Noterdaeme, J. M.

AU - Würsching, E.

PY - 2005/3/1

Y1 - 2005/3/1

N2 - The coupling characteristics of the ion cyclotron range of frequencies antenna during type I edge localized modes (ELMs), asymmetries in the reaction of toroidally distributed antennas to ELMs and arcing phenomena following ELMs are studied for ASDEX Upgrade. The maximum change of the antenna resistance due to ELMs increases with triangularity δL in the on-axis minority heating. In the cases with off-axis heating, the change of the resistance is less sensitive to δL. Time-resolved RF measurements show asymmetries in times of response of the toroidally distributed antennas to the rising edge of ELMs and in the further evolution of this response. Toroidal propagation of ELM perturbations in counter-current direction with times ≈50 μs for one toroidal turn is observed. ELM-induced arcing is observed during ELMs and with delays after ELMs. Conditioning takes place as the arc number during ELMs decreases and time delay between ELM and arc increases.

AB - The coupling characteristics of the ion cyclotron range of frequencies antenna during type I edge localized modes (ELMs), asymmetries in the reaction of toroidally distributed antennas to ELMs and arcing phenomena following ELMs are studied for ASDEX Upgrade. The maximum change of the antenna resistance due to ELMs increases with triangularity δL in the on-axis minority heating. In the cases with off-axis heating, the change of the resistance is less sensitive to δL. Time-resolved RF measurements show asymmetries in times of response of the toroidally distributed antennas to the rising edge of ELMs and in the further evolution of this response. Toroidal propagation of ELM perturbations in counter-current direction with times ≈50 μs for one toroidal turn is observed. ELM-induced arcing is observed during ELMs and with delays after ELMs. Conditioning takes place as the arc number during ELMs decreases and time delay between ELM and arc increases.

KW - ASDEX Upgrade

KW - ELM

KW - ICRF antenna

KW - RF discharge

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M3 - Article

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SP - 776

EP - 780

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

IS - 1-3 SPEC. ISS.

ER -

Influence of ELMs on operation of ICRF antennas in ASDEX Upgrade

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Keywords

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