JET-C(98)33

Stability of Alpha Particle Driven Alfvén Eigenmodes in High Performance JET D-T Plasmas

The transport of fusion-born alpha particles (a's) is a key issue for deuterium-tritium (DT) plasma in a tokamak reactor, as it influences the plasma heating profile, the magnitude of alpha losses and the distribution of the helium ash. Over the a-particle slowing down time the fast ion radial transport can be significantly enhanced over the neoclassical level by the presence of Alfvén Eigenmodes (AEs) which resonate with fast ions. These modes, which are associated with the frequency gaps of the shear Alfvén spectrum in toroidal plasmas, were extensively studied in JET deuterium plasmas using various excitation methods [1]. High fusion power DT experiments on JET (Table I) have made feasible direct experimental investigations of AE stability in the presence of a-population with MW.
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JETC98033 103.11 Kb