Individual Sawtooth pacing by synchronized ECCD in TCV

Previous real-time sawtooth control scenarios using EC actuators have attempted to shorten [1] or lengthen [2] the sawtooth period by optimally positioning the EC absorption near the q=1 surface. In new experiments we demonstrate for the first time that individual sawtooth crashes can be repetitively induced at predictable times by reducing the stabilizing ECCD power after a predetermined time from the preceding crash. Other stabilizing actuators ( e. g. ICRF, NBI) are expected to produce similar effects. Armed with these results, we present a new sawtooth / NTM control paradigm for improved performance in burning plasmas. The potential appearance of neo-classical tearing modes, triggered by long period sawtooth crashes even at low beta, becomes predictable and therefore amenable to preemptive ECCD. The ITER Electron Cyclotron Upper Launcher (EC-UL) design incorporates the needed functionalities for this method to be applied. The methodology and associated TCV experiments will be presented.


Published in:
Radio Frequency Power in Plasmas: Proceedings of the 19th Topical Conference, 1406
Presented at:
19th Topical Conference on Radio Frequency Power in Plasmas, US-Japan Workshop on RF Physics, Newport, USA, June 1-3, 2011
Year:
2011
Publisher:
AIP conference Proceedings
ISBN:
978-0-7354-0978-1
Keywords:
Laboratories:
SPC
CRPP




 Record created 2012-05-04, last modified 2018-01-28


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