The dedicated ICRH system for the stellarator Wendelstein 7-X

Journal Article · Wed Feb 12 00:00:00 EST 2014 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4864508· OSTI ID:22263843

Ongena, J.; Messiaen, A.; Dumortier, P.; Durodie, F.; Kazakov, Ye. O.; Louche, F.; Schweer, B.; Vervier, M.; Van Eester, D.; Koch, R.; Krivska, A.; Lyssoivan, A.; Van Schoor, M.; Wauters, T. ^[1]; Borsuk, V.; Neubauer, O.; Schmitz, O. ^[2]; Offermans, G. ^[3]; Altenburg, Y.; Baylard, C. ^[4] ; others, and

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1. Laboratory for Plasmaphysics, Ecole Royale Militaire - Koninklijke Militaire School, TEC Partner, Brussels (Belgium)
2. IEK-4 / Plasmaphysik, Forschungszentrum Juelich, TEC Partner, Juelich (Germany)
3. ZEA-1, Forschungszentrum Juelich, Juelich (Germany)
4. Max-Planck Institute für Plasmaphysik, Teilinstitut Greifswald, Greifswald (Germany)

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.

• OSTI ID: 22263843
• Journal Information: AIP Conference Proceedings, Vol. 1580, Issue 1; Conference: 20. topical conference on radiofrequency power in plasmas, Sorrento (Italy), 25-28 Jun 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANTENNAS
CAPACITORS
COUPLING
DEPOSITION
ELECTRIC POTENTIAL
ICR HEATING
ION CYCLOTRON-RESONANCE
MHZ RANGE
PLASMA RADIAL PROFILES
PULSES
SCATTERING
SPECTRA
TRIPLETS