Particle Control in Tore Supra with Pump Limiters and Ergodic Divertor

Tore Supra is a superconducting limiter tokamak designed for long and high-power discharges. In its initial phase, the plasma density control was handled by a set of seven modular limiters (total area [approximately]1.5 m²) equipped with pumps. An inner wall ([approximately]10 m²), covered with actively cooled carbon tiles, was used to handle high-power discharges. An ergodic divertor (ED), composed of six modules, was installed on the low-field side to create a stochastic edge layer for enhancing the edge radiation; all the modules were equipped with neutralizer plates and a pumping system. The performances, in terms of pumping capabilities and density control, are reported for the modular pump limiters and the ED modules, equipped with neutralizer plates for particle collection. Throat and vented geometries, respectively collecting ions and neutrals, were tested for the modular limiters and the ED. After 12 years of operation, a major upgrade (Composants Internes et Limiteur project) resulted in the replacement of all these plasma-facing components by a flat toroidal pump limiter (total area [approximately]7.6 m²) actively cooled and located at the bottom of the machine. Long discharges (6 min) with high energy input (>1.0 GJ) have been performed repetitively, in steady-state conditions.