Present experiments with ion-cyclotron heating are mainly devoted to study ion-cyclotron resonance heating of hydrogen and 3He in a deuterium plasma. However, for a thermonuclear fusion experiment this frequency range has the undesirable feature of turning into α-particle heating as soon as alpha particles are created. Because of the large Doppler broadening of their resonance, a significant amount of power is then absorbed in the outer part of the plasma. To avoid this drawback, the use of second-harmonic minority heating of hydrogen or 3He is suggested. Second-harmonic heating of 3He in a deuterium plasma can also be used to study fusion and α-particle confinement without creating a large neutron flux. The absorption for these scenarios is found to be strong as long as mode conversion occurs between the fast magneto-acoustic wave and the ion Bernstein wave. The propagation of the fast wave and its interaction with the ion Bernstein wave have been calculated with a finite-element code in plane geometry.
Fast wave heating at intermediate ion cyclotron harmonics on the JIPP T-IIU tokamak