Characteristics of Ion Bernstein Wave heating on the JIPP T-IIU tokamak

Ion Bernstein Wave (IBW) heating has been examined on the JIPP T-IIU tokamak under two different conditions referred to as Mode-I and Mode-II. In the Mode-I regime, a wave is launched on an IBW branch between the third and fourth cyclotron harmonics of deuterium ions. In the Mode-II regime, a wave is launched on a branch between the second and third cyclotron harmonics. These two modes show quite different heating characteristics. The causes of this difference are analysed by using a simple model to determine the kparallel spectrum of the excited wave and by applying a ray tracing code. In connection with the Mode-I experiment as discussed in a previous report (1985), two important new experimental results are obtained. It is shown that an IBW heats the core of the plasma rather than causing plasma-edge interactions, as anticipated. It is also shown that the energy tail of the hydrogen ions is higher than that of the deuterium ions, which indicates that the responsible heating mechanisms are different. (author). 18 refs, 15 figs