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Abstract

Sawtooth instabilities are periodic relaxations of the plasma core parameters in standard tokamak scenarios. They have beneficial effects such as the ejection of impurities, the removal of Helium ashes, or can have negative effects such as the trigger of pressure limiting neo-classical tearing modes or of other coupled MHD (e.g. X-event leading to disruption). The prediction of the sawtooth period or the possibility of controlling their amplitude in ITER is therefore of importance.

Energetic particles resulting from either ion cyclotron resonance heating (ICRH) or fusion reactions are known to have a strong stabilising influence on the behaviour of sawtooth oscillations in tokamaks. The role of the lower-energy fast particles in neutral beam injection (NBI) is less apparent, although stabilisation was observed directly. It has also been observed indirectly in tritium experiments in the Joint European Torus (JET) with (NBI), where an increase of the sawtooth period with tritium concentration was explained as a stabilising effect of NBI. In such an interpretation the NBI fast ion energy content is changing due to the mass dependence of the slowing-down time. .

Additional information

Authors: POCHELON A, Centre de Recherches en Physique des Plasmas, EURATOM Association-Confederation Suisse, Ecole Polytechnique Federale de Lausanne (CH);ANGIONI C, Centre de Recherches en Physique des Plasmas, EURATOM Association-Confederation Suisse, Ecole Polytechnique Federale de Lausanne (CH);SAUTER O, Centre de Recherches en Physique des Plasmas, EURATOM Association-Confederation Suisse, Ecole Polytechnique Federale de Lausanne (CH);MANTSINEN M, Helsinki University of Technology, Association-EURATOM-Tekes, Espoo (FI);GORELENKOV N, Princeton Plasma Physics Laboratory, New Jersey (US);BUDNY R, Princeton Plasma Physics Laboratory, New Jersey (US);HOWELL D.F, EURATOM/UKAEA Fusion Association, Abington (UK);SHARAPOV S, EURATOM/UKAEA Fusion Association, Abington (UK);DE VRIES P.C, FOM-Instituut voor Plasmafysica, Nieuwegein (NL);NAVE M.F.F, Associacao Euratom/IST, Centro de Fusao Nuclear, Lisbon (PT)
Bibliographic Reference: An oral report given at: The 28th EPS Conference of Controlled Fusion and Plasma Physics. Held in: Madeira (PT) June 2001
Record Number: 200013700 / Last updated on: 2001-09-18
Category: PUBLICATION
Original language: en
Available languages: en