Recent advances of RF systems for magnetic fusion

The physics and technology advances in ECRF, ICRF and LHCD systems for the next steps in fusion research are reviewed. The areas where further progress is necessary are identified and discussed. Although many difficulties in technology and physics understanding have been solved, all systems proposed for ITER require specific R&D and no single system can accomplish all the tasks required for its mission. This is particularly true for long pulse operation which is challenging due to demanding plasma beta requirements and off-axis current drive efficiency. Such a regime requires several efficient plasma actuators working at the same time to provide central heating (preferably ions), local instability stabilisation and off-axis current drive. Valuable experience is available from presently operating facilities and will be considerably strengthened by several new super conducting devices becoming on line.