@inproceedings{5b5863cf4630444b859baf806e8e36fb,
title = "The dedicated ICRH system for the stellarator Wendelstein 7-X",
abstract = "The current status of the mechanical and electromagnetic design for the ICRF antenna system for W7-X is presented. Two antenna plugins are discussed: one consisting of a pair of straps with pre-matching to cover the first frequency band 25-38 MHz and a second one consisting of two short strap triplets to cover a frequency band around 76 MHz. This paper focusses on the two strap antenna for the lower frequency band. Power coupling of the antenna to a reference plasma profile is studied with the help of the codes TOPICA and Microwave Studio, that deliver the scattering matrix needed for the optimization of the geometric parameters of the straps and antenna box. Radiation power spectra for different phasings of the two straps are obtained using the code ANTITER II and different heating scenarii are discussed. The potential for heating, fast particle generation and current drive is discussed. The problem of RF coupling through the plasma edge and of edge power deposition is summarized. The system contains a prematching capacitor to limit the maximum voltage in the system, and the large mutual coupling between the 2 straps is counterbalanced by the use of a decoupler. The mechanical design highlights the challenges encountered with this antenna: adaptation to a large variety of plasma configurations, the limited space within the port to accommodate the necessary matching components and the watercooling needed for long pulse operation.",
keywords = "5-ports junction, ICRH, W7-X. coupling, decoupler, matching",
author = "J. Ongena and A. Messiaen and P. Dumortier and F. Durodie and Kazakov, {Y. O.} and F. Louche and B. Schweer and M. Vervier and {Van Eester}, D. and R. Koch and A. Krivska and A. Lyssoivan and {Van Schoor}, M. and T. Wauters and V. Borsuk and O. Neubauer and O. Schmitz and G. Offermans and Y. Tenburg and C. Baylard and D. Birus and S. Bozhenkov and Hartmann, {D. A.} and J. Kallmeyer and S. Renard and R. Wolf",
year = "2014",
doi = "10.1063/1.4864508",
language = "English",
isbn = "9780735412101",
series = "AIP Conference Proceedings",
publisher = "American Institute of Physics Inc.",
pages = "105--112",
booktitle = "Radiofrequency Power in Plasmas - Proceedings of the 20th Topical Conference",
note = "20th Topical Conference on Radiofrequency Power in Plasmas ; Conference date: 25-06-2013 Through 28-06-2013",
}