Concept and Results of New Operation Scheme with Improved Control System for Radio Frequency Heating in JT-60U

The control system of the RF heating system in JT-60U has been improved with the concept of dispersion processing and by featuring a real-time waveform shaping method. The new dispersion processing system has higher performance and reliability than the old single-processor system before modification. Moreover, improvement of operator role sharing, using the real time waveform shaping has enabled more efficient and smooth operation. In the typical role sharing, a simple rectangular waveform of the RF heating power is set by the experiment operator, and the waveform is reshaped with the parameter set by the RF operator who is familiar with the condition of the RF system at that time. The simple and flexible composition of the new control system will also enable further improvement of hardware to enhance plasma performance and facilitate fusion experiments.