Neutral beam heating of tokamaks: Past performance and future applications

Neutral beam heating of tokamak plasmas has now a history of about one decade. The evolution of these heating systems from those of the early 1970’s to those of the present has been most impressive in terms of size, power, voltage, etc., but also in terms of performance in the sense of the plasma parameters achieved. Future needs for tokamak heating systems have highlighted certain shortcomings of neutral beam systems as they presently exist, and have been the driver behind an effort which has led to many conceptual improvements which should make neutral beams a serious contender for future tokamak heating requirements. A brief history of the highlights of neutral beam–tokamak systems of the last decade and some projections of future applications will be presented.