A remotely steered millimetre wave launcher for electron cyclotron heating and current drive on ITER

TitleA remotely steered millimetre wave launcher for electron cyclotron heating and current drive on ITER
Publication TypeJournal Article
Year of Publication2010
AuthorsW.A Bongers, MF Graswinckel, A.PH Goede, W. Kasparek, I. Danilov, A.F Curto, MR de Baar, M.A van den Berg, A.JH Donne, B.SQ Elzendoorn, R. Heidinger, P. Ivanov, O.G Kruijt, B. Lamers, A. Meier, B. Piosczyk, B. Plaum, D.MS Ronden, D.J Thoen, M. Schmid, A.GA Verhoeven
JournalFusion Engineering and Design
Volume85
Number1
Pagination69-86
Date PublishedJan
Type of ArticleArticle
ISBN Number0920-3796
Accession NumberISI:000274284900012
Keywords140 GHZ, ANTENNA, BEAMS, DESIGN, ECRH, electron cyclotron heating and current drive, GUIDE, ITER, LOSSES, Remote steering launcher, SYSTEM, TEARING MODE STABILIZATION, TESTS
Abstract

High-power millimetre wave beams employed on ITER for heating and Current drive at the 170 GHz electron cyclotron resonance frequency require agile steering and tight focusing of the beams to suppress neoclassical tearing modes. This paper presents experimental validation of the remote steering (RS) concept of the ITER upper port millimetre wave beam launcher. Remote steering at the entrance of the upper port launcher rather than at the plasma side offers advantages in reliability and maintenance of the mechanically Vulnerable steering system. A one-to-one scale mock-up consisting of a transmission line, mitre bends, remote steering unit, vacuum window, square corrugated waveguide and front mirror simulates the ITER launcher design configuration. Validation is based on low-power heterodyne measurements of the complex amplitude and phase distribution of the steered Gaussian beam. High-power (400 kW) short Pulse (10 ms) operation under vacuum, diagnosed by calorimetry and thermography of the near- and far-field beam patterns, confirms high-power operation, but shows increased power loss attributed to deteriorating input beam quality compared with low-power operation. Polarization measurements show little variation with steering, which is important for effective current drive requiring elliptical polarization for O-mode excitation. Results show that a RS range Of LIP to -12 to +12 can be achieved with acceptable beam quality. These measurements confirm the back-up design of the ITER ECRH&CD launcher with future application for DEMO. (C) 2009 Elsevier B.V. All rights reserved.

URL<Go to ISI>://000274284900012
Division

Fusion Physics

PID

922bc04c5c84732968401eafc73145e5

Alternate TitleFusion Eng. Des.

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