Elsevier

Fusion Engineering and Design

Volume 123, November 2017, Pages 285-288
Fusion Engineering and Design

Commissioning and first results of the reinstated JET ICRF ILA

https://doi.org/10.1016/j.fusengdes.2017.05.050Get rights and content
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Highlights

  • The JET ICRF ITER-like Antenna (ILA) has been reinstated.

  • A comprehensive calibration and verification of all RF measurements has been performed.

  • New algorithms were implemented for the second stage matching and the – toroidal and poloidal – phase control of the array.

  • The operating space has been extended towards lower and upper frequencies (29–51 MHz) and to toroidal dipole and current drive phasings.

Abstract

The JET ICRF ITER-like Antenna (ILA) has been operated at 33, 42 and 47 MHz in 2008–2009 but stopped operation in 2009 due to the failure of one of the tuning capacitors inside the antenna. Tests on a spare capacitor showed that a micro-leak was caused by the cycle wear of a capacitor’s internal bellows. The ILA was reinstated with a new operating scheme minimizing the full stroke requests of the capacitor.

This contribution gives an overview of the works undertaken to reinstate the JET ILA up to the first results on plasma.

The capacitors were replaced and high voltage tests of the capacitors were performed. An extensive calibration of all the measurements in the RF circuit was carried out. New simulation tools were created and control algorithms were implemented for the – toroidal and poloidal – phase control of the array as well as for the matching of the second stage. New protections are being implemented for the thermal and voltage protection of the capacitors. Low voltage matching tests were performed before the high power commissioning. Finally the first results on plasma are presented, showing that the new controls allow extending the range of the operation to lower (29 MHz) and higher (51 MHz) frequencies than previously achieved.

Keywords

JET
ICRF
ICRH
ILA
Antenna

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1

See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia.