The present role of small tokamaks

Small tokamaks have provided close support to their bigger brothers since the beginning of tokamak research, leading to improvements in operation and understanding through programmes of work aimed at elucidating the basic plasma physics underlying tokamak phenomena. They have proved flexible and quick to respond to testing new ideas and have pioneered a number of advanced concepts now being pursued on the major tokamaks. Many of the experimentalists, operators and diagnosticians of tomorrow's large machines will have trained on the small tokamaks of today. These devices have an important role to play in providing input to the ITER physics R&D tasks and to the development and implementation of new diagnostics. About 50 'small' tokamaks are currently in operation, focusing on a wide range of physics issues. Assessment of the output from these small devices shows that there need to be stronger links between the small and large tokamaks.