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Abstract

Precise control of the plasma position and shape during a discharge is important for several reasons. The vertical movement, unstable in shaped TCV plasmas, must be under optimised feedback control in order to achieve the highest performance. The radial position must be maintained to respect plasma-wall spacing. The elongation and triangularity must be closely controlled at high current to maintain the safety factor close to its limits. These requirements are met in the steady state by precise measurement algorithms, but when the plasma shape or internal parameters are changing rapidly, the dynamic properties of the different feedback loops become crucial. In order to study these effects, perturbation injection experiments have been performed. A linear interpretation of the results requires simple models of the plasma behaviour and of the coil and vessel system. The shape of the TCV vacuum vessel is such that more than one vessel eigenmode must be retained. The control loops can have integral feedback as well as proportional and derivative terms.

Additional information

Authors: LISTER J B, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH);MARTIN Y, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH);MORET J-M, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne (CH)
Bibliographic Reference: Article: Proceedings of the 21st EPS Conference on Controlled Fusion and Plasma Physics, pp. 1558-1561
Record Number: 199510148 / Last updated on: 1995-08-22
Category: PUBLICATION
Original language: en
Available languages: en