Performance and development of heating and current drive systems in JT-60U

Fujii, Tsuneyuki; Kasugai, Atsushi; JT-60 Team

The key factors to realize highly integrated performance plasma performances are control of profiles of current, pressure, rotation and so on. Therefore, several types of heating and current drive systems, ECH, LH, ICH, negative and positive ion based NBI systems, have been introduced into JT-60U. The ECH system with output power 4MW at 110 GHz has been developed using four 1 MW gyrotrons. The gyrotron has achieved 1MW-5sec output of the designed value by suppressing the parasitic oscillation with SiC RF absorber built-in. This gyrotron may get higher output power because it can adjust the anode voltage and extend the range of oscillation parameters. The NBI system has been attained 5.8 MW at 400 kV of beam energy with the negative ion based one and 28 MW with the positive ion based one. In a development work of the negative ion based NBI system, a detailed study on beamlet steering for multi-beam focusing was done, including of the space charge effects among beamlets. Then, 2.6 MW for 10s has been achieved.