Fuelling and particle exhaust in present day and next step tokamaks

Particle control in next step tokamaks is required to ensure balanced D and T concentrations in the plasma core (burn control), high divertor density (highly radiating divertor, detached operation) and not too large scrape off density conditions (access to H mode and critical density). This requires proper exhaust and fuelling schemes to be operated, compatible with helium ash removal requirements. Particle transport, as well as exhaust and fuelling methods, are reviewed. The present scheme foreseen for ITER and related prospects are also discussed. Copyright (C) 1996 Elsevier Science Ltd.