@inproceedings{7c0f7c15e0004d1dbfaa8834d2a0c557,
title = "Estimation of sheath potentials in front of ASDEX Upgrade ICRF antenna with SSWICH asymptotic code",
abstract = "Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating became problematic in ASDEX Upgrade (AUG) tokamak after coating of ICRF antenna limiters and other plasma facing components by tungsten. Strong impurity influx was indeed produced at levels of injected power markedly lower than in the previous experiments. It is assumed that the impurity production is mainly driven by parallel component of Radio-Frequency (RF) antenna electric near-field E//that is rectified in sheaths. In this contribution we estimate poloidal distribution of sheath Direct Current (DC) potential in front of the ICRF antenna and simulate its relative variations over the parametric scans performed during experiments, trying to reproduce some of the experimental observations. In addition, relative comparison between two types of AUG ICRF antenna configurations, used for experiments in 2014, has been performed. For this purpose we use the Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code and asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating (SSWICH) code. Further, we investigate correlation between amplitudes of the calculated oscillating sheath voltages and the E//fields computed at the lateral side of the antenna box, in relation with a heuristic antenna design strategy at IPP Garching to mitigate RF sheaths.",
author = "\{ASDEX Upgrade Team\} and A. K{\v r}ivsk{\'a} and V. Bobkov and L. Colas and J. Jacquot and D. Milanesio and R. Ochoukov",
note = "Funding Information: 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 was carried out using the HELIOS supercomputer system at Computational Simulation Centre of Inter-national Fusion Energy Research Centre (IFERC-CSC), Aomori, Japan, under the Broader Approach collaboration between Euratom and Japan, implemented by Fusion for Energy and JAEA.; 21st Topical Conference on Radiofrequency Power in Plasmas ; Conference date: 27-04-2015 Through 29-04-2015",
year = "2015",
month = dec,
day = "10",
doi = "10.1063/1.4936490",
language = "English",
series = "AIP Conference Proceedings",
publisher = "American Institute of Physics Inc.",
editor = "Pinsker, \{Robert I.\}",
booktitle = "Radio Frequency Power in Plasmas",
}