Application of intermediate frequency range fast wave to JIPP T-IIU plasma

A series of experiments using a newly constructed 130 MHz RF system has been conducted on the JIPP T-IIU tokamak since 1989. It is predicted theoretically that the fast wave in this range of frequency weakly interacts with particles. Though weak, two mechanisms of wave absorption were identified in the experiment: electron Landau/transit-time damping and 3rd ion cyclotron harmonic heating. The former has an intimate connection with fast wave current drive and the latter can provide a new regime of plasma heating or a possible method of controling transport of α-particles. It was found that the efficiency of the 3rd cyclotron heating is improved by using it in the combination with NBI and ICRF heating. The heating efficiency obtained is as high as that of conventional heating. The experimental results are also analyzed on the basis of a theory of the global wave which takes into account wave particle interactions. These mechanism of wave particle interactions are competing with each other as they will be under more realistic reactor conditions. (author)