DocumentCode :
2760154
Title :
Progress in the Development of RF Driven Negative Ion Sources for ITER NBI
Author :
Fröschle, M. ; Speth, E. ; Falter, H. ; Fantz, U. ; Franzen, P. ; Riedl, R. ; Heinemann, B. ; Kraus, W. ; Martens, Ch. ; McNeely, P. ; Tanga, A. ; Holtum, D. ; Encheva, A.
Author_Institution :
EURATOM Assoc., Max-Planck-Inst. fur Plasmaphys., Garching
fYear :
2005
fDate :
Sept. 2005
Firstpage :
1
Lastpage :
4
Abstract :
The neutral beam injection (NBI) system for ITER is at present based on arc sources which suffer up to now from a limited lifetime of the tungsten filaments and from unacceptable plasma non-uniformity. Inductively coupled radio frequency (RF) sources, which have successfully been developed at IPP Garching for positive ion based NBI, offer substantial advantages for ITER. Since December 2002 the development of a large area RF source for negative ions is supported through an official EFDA task agreement. This development is carried out at IPP on three different test facilities: "BATMAN" is devoted to the physical understanding of the underlying processes of the negative ion formation, but with small extraction areas (<100 cm2) and short pulses (<10 s). The calorimetric H- and D- current density has already exceeded ITER requirements. Source filling pressure and electron to ion ratio are compatible with ITER requirements. Test facility "MANITU" focuses mainly on long pulse operation (3600 s) and larger extraction areas (300 cm2). The system has been operational since spring 2005 but still requires improvements with respect to reliability. The "RADI" test bed is dedicated to demonstrate plasma uniformity and the modular concept of the RF source, by scaling up the size of the source to half the size of the ITER source. The new "Half-Size Source" with about the width and half the height of the ITER source will be delivered within the next weeks. Full size extraction however will not be possible, but a dummy grid will simulate the gas conductance of the ITER source
Keywords :
Tokamak devices; arcs (electric); fusion reactor design; fusion reactor ignition; fusion reactor operation; ion sources; plasma beam injection heating; plasma density; plasma radiofrequency heating; plasma sources; tungsten; BATMAN; D-; EFDA task agreement; H-; Half-Size Source; IPP Garching; ITER; MANITU; NBI; RADI test bed; RF driven negative ion sources; arc sources; calorimetric current density; electron-ion ratio; gas conductance; inductively coupled radio frequency sources; long pulse operation; negative ion formation; neutral beam injection; plasma nonuniformity; plasma uniformity; positive ion; source filling pressure; test facilities; tungsten filaments; Current density; Electrons; Filling; Ion sources; Particle beam injection; Particle beams; Plasma sources; Radio frequency; Test facilities; Tungsten; BATMAN test bed; Half-Size Source; ITER NBI; ITER source; MANITU test bed; NNBI; RADI test bed; RF ITER source; RF source; negative ion source;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Fusion Engineering 2005, Twenty-First IEEE/NPS Symposium on
Conference_Location :
Knoxville, TN
Print_ISBN :
0-4244-0150-X
Electronic_ISBN :
0-4244-0150-X
Type :
conf
DOI :
10.1109/FUSION.2005.252938
Filename :
4018972
Link To Document :
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