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Abstract

Since 1994, an Electron Cyclotron Resonance Heating and Current Drive (ECRH/ECCD) 118GHz-2.4MW-10min, is under development for the Tore Supra (TS) tokamak. The antenna has three plane mobile mirrors to control torodial and poloidal injection angles of the beam. The polarization control system is located at the gyrotron output in the MOU (Matching Optic Unit) after the cryogenic window. This MOU allows complete control of the polarization of the wave using two corrugated mirrors. Ordinary mode (O mode: E parallel to Bt) injection is used on TS at the maximum toroidal field; by reducing the toroidal field extraordinary mode (X mode: E vertical to Bt) can also be used. To study: transport, MHD control, co-current and counter-current ECCD, synergy heating and current drive with Lower Hybrid waves in plasma experiments, it is important to change the power deposition profile by adjustment of the injected beam direction. Thus, the polarization of the injected beam is a function of four parameters: the two polarization mirror angles and the two injection angles. We can calculate, for each set of injection angles, the required settings for the two polarization mirrors to achieve the desired polarization of the injected wave. In the present TS ECHR power measurement system, situated after the polarization system, only one electric field direction is measured. In order to always have a good signal/ noise ratio when we change the polarization, we must turn the rectangular measurement horn by 90 degrees in certain cases. As a consequence, we have three difficulties: this intervention is not practical, not very reproducible and the coupling in the two directions is different. This leads to doubts about the injected power when we change the polarization and a difficulty to test X mode or O mode. In order to improve the precision of the beam injected in the plasma we have proposed: to measure the transfer function of the MOU in laboratory, to compare it with the calculation using

Additional information

Authors: BERGER-BY G ET AL, Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: An oral paper given at: 13th Joint Workshop on ECE and ECRH Held in: Russia
Availability: Available from Association EURATOM-CEA, Departement de Recherches sur la Fusion Controlee, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: dirdrfc@drfc.cad.cea.fr
Record Number: 200417522 / Last updated on: 2004-06-11
Category: PUBLICATION
Original language: en
Available languages: en
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