Optimisation of the ITER ECRH top launcher
The ITER ECRH system is presently foreseen to transfer the EC power to the plasma through two different launching structures: a midplane launcher mainly designed for heating and current drive in the core plasma, and a top launcher especially aimed at the stabilisation of MHD instabilities, most prominently the Neoclassical Tearing Mode (NTM). The study presented in this paper should assess how the top launcher can be optimised to best fulfil its tasks. For an ITER-FEAT reference scenario (Elmy-H mode, Q=10), results from different codes for a benchmark case are presented, referred to a common definition of the ECW beam. The possibility to control the (1,1) mode by localised ECRH/ECCD near the q=1 surface is considered for the reference frequency f=170 Ghz. For (3,2) and (2,1) NTMs stabilisation, the advisability to minimize the beam width by launching focussed beams is pointed out. Moreover, both the location of the launcher and the gyrotron frequency are varied to find the best solution in terms of the "figures of merit" for NTMs stabilisation, IECCD/d and IECCD/d2, where d is the deposition width. The poloidal steering range required to change the radial position of the ECCD location is also shown.
Bibliographic Reference: An oral paper given at: 2nd IAEA Technical Meeting on ECRH Physics and Technology for ITER Organised by: International Atomic Energy Agency Held at: Kloster Seeon, Germany, July 14-16, 2003
Availability: Available free of charge online at: http://www.rijnh.nl/ITERECRH/archief/P067.pdf
Record Number: 200317044 / Last updated on: 2003-10-29
Original language: en
Available languages: en