Design of the ITER Upper Port Electron Cyclotron Heating and Current Drive System Based on Remote Steering

Graswinckel, M.F.; Berg, M.A. van den; Bongers, W.A.; Donné, A. J. H.; Goede, A. P. H.; Cardozo, Niek Lopes; Ronden, D.; Verhoeven, A.G.A.

doi:10.13182/fst08-a1666

Cited by 5 publications

(11 citation statements)

References 17 publications

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“…Here, the poloidal (vertical) beam dimensions at the location of wave absorption serve as a proxy to η ntm [15]. Spatial envelope and heat load on the individual beam line components serve as a constraint.…”

Section: Methods Of Launcher Performance Analysis and Optimisationmentioning

confidence: 99%

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Advanced launcher design options for electron cyclotron current drive on ITER based on remote steering

Graswinckel¹,

Bongers²,

Baar³

et al. 2008

Nucl. Fusion

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Abstract. Electron Cyclotron Current Drive (ECCD) will become the main scheme on ITER for the stabilization of neoclassical tearing modes (NTM) and the control of sawtooth oscillations. The effectiveness of this scheme forms the basis for the requirements of the ITER Upper Port Launcher (UPL). These requirements include the need for steering the mm-wave beam to the pertinent magnetic flux surfaces where the instability develops. Several concepts have been explored; Front Steering where a system of movable mirrors is situated at the plasma-facing end of the launcher; Remote Steering (RS) where the movable mirror system is situated at the back end of the launcher system. The advantage of the Remote Steering concept is that moving parts are placed away from the plasma in a secondary vacuum system, less exposed to plasma neutron flux, thus offering advantages in reliability and safety of the machine. Also, contamination of the beam steering unit by Be and T is less of a problem. However, beam-focusing properties of the RS launcher deteriorate with increased steering angle, which limits the NTM stabilisation performance as compared with Front Steering. In this paper, recent improvements in the RS design are presented. The stabilisation efficiency calculated reaches values that meet most of the ITER requirements. Improvements include non-spherical front mirrors and a tapered Square Corrugated Waveguide. Rather than steering all mm-wave beams over the entire vertical height range specified, RS launchers with a limited steering range are explored, yielding a performance improvement of 25 % with an acceptable mm-wave heat load of 5.7 MW/m 2 on the front mirrors. This result leads to a dual launcher concept with one set of beams dedicated to control NTMs at the outward lying q=2 surface and another set of beams dedicated to control NTMs at the inward lying q=3/2 surface in combination with saw teeth control at the innermost q=1 surface.

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Section: Methods Of Launcher Performance Analysis and Optimisationmentioning

confidence: 99%

“…Designs presented earlier include a short and a long SCW variant [15]. The long waveguide variant allows for a wider waveguide cross section that improves the beam quality at extreme steering angles.…”

Section: Increasing the Scw Dimensionsmentioning

confidence: 99%

Advanced launcher design options for electron cyclotron current drive on ITER based on remote steering

Graswinckel¹,

Bongers²,

Baar³

et al. 2008

Nucl. Fusion

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show abstract

“…Various options of the RS concept have been explored and optimised in terms of effectiveness in NTM suppression [7]. Optimisation of the quasi-optical design has been carried out by [8].…”

Section: What Are the Requirementsmentioning

confidence: 99%

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

Bongers¹,

Graswinckel²,

Goede³

et al. 2010

Fusion Engineering and Design

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“…The light-grey area indicates the present limited range. Further optimization of the optics led to a reduction of the peak power densities on the mirrors to approximately 5.9 MW/m 2 [7]. Table 1 presents the launcher performance Á NTM at the q = 2/1 and q = 3/2 surface for the three reference plasma scenarios.…”

Section: Reduced Scanning Rangementioning

confidence: 99%

“…Launcher ÁNTM of October 2005 baseline[7] (with full scanning range) and ÁNTM of the launcher with a limited range, from which q = 3/2 for scenario 3a was dropped[4] …”

mentioning

confidence: 99%

Finalization of the conceptual design of the remote steering ECH launcher for ITER

Ronden

Baar

Berg

et al. 2009

Fusion Engineering and Design

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Design of the ITER Upper Port Electron Cyclotron Heating and Current Drive System Based on Remote Steering

Cited by 5 publications

References 17 publications

Advanced launcher design options for electron cyclotron current drive on ITER based on remote steering

Advanced launcher design options for electron cyclotron current drive on ITER based on remote steering

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

Finalization of the conceptual design of the remote steering ECH launcher for ITER

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