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S. Martini, R. Piovan1, T. Bolzonella,
G. Chitarin, P. Innocente, P. Sonato, D. Terranova,
P. Zanca, G. Zollino
Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
1 also at INFM unità di Padova
Abstract. The RFP configuration is maintained by an intrinsic dynamo mechanism
associated to resistive MHD tearing modes. These dynamo modes are responsible
for field line stochasticity and have a strong influence on plasma
confinement. RFX results relevant to the subject are discussed both in terms
of the influence of the magnetic boundary and of the characteristics of the
RFP enhanced confimenement regimes. The dynamo modes are often locked in phase
and to the wall, which spoils the stabilising effect of the conducting shell
and leads to severe plasma-wall interactions. The driven rotation of the
locked dynamo modes has been studied in RFX by means of a new Toroidal Field
Modulation System. A rotating toroidally localised perturbation of the
toroidal magnetic field couples to the modes and induces their rotation.
IAEA 2001
