Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6746350 | Fusion Engineering and Design | 2015 | 4 Pages |
Abstract
Ion Cyclotron Resonance Heating (ICRH) is a promising heating and wall conditioning method considered for the W7-X stellarator and a dedicated ICRH antenna has been designed. This antenna must perform several tasks in a long term physics programme: fast particles generation, heating at high densities, current drive and ICRH physics studies. Various minority heating scenarios are considered and two frequency bands will be used. In the present work a design for the low frequency range (25-38Â MHz) only is developed. The antenna is made of 2 straps with tap feeds and tuning capacitors with DC capacitance in the range 15-200Â pF. These capacitors introduce additional constraints on the optimisation and on the maximum amount of power that can be coupled to the plasma: not only the capacitor voltages cannot exceed a certain value (42Â kV) but also the currents are limited to approximately 740Â A rms to ensure sufficient heat dissipation for the considered duty cycle. Starting from an initial geometry we used the tridimensional electromagnetic software CST MicroWave Studio (MWS) to assess and optimise its coupling properties. By modifying some geometrical parameters of the front face (strap width, antenna box depth, strap length, strap feeders shape), we show that a substantial increase in maximum coupled power can be obtained accounting for the technical constraints on the capacitors. The various steps of the optimisation are validated with TOPICA simulations. For a given density profile the RF power coupling expectancy can be precisely computed.
Related Topics
Physical Sciences and Engineering
Energy
Energy Engineering and Power Technology
Authors
F. Louche, A. KÅivská, A. Messiaen, J. Ongena, V. Borsuk, F. Durodié, B. Schweer,