Ion cyclotron heating of the JET plasma

The numerical code RAYIC has been used to investigate three ion cyclotron heating scenarios of the JET plasma: a) He3++ minority in a hydrogen plasma; b) first harmonic heating of a deuterium plasma; c) H+ minority in a hydrogen plasma. The dependence of absorption on the discharge parameters (density, temperature, minority concentration, etc.) is discussed in terms of elementary damping mechanisms: wave conversion, ion cyclotron damping, electron transit time and Landau damping. All three methods are found to be satisfactorily efficient for typical JET extended phase performances. Use of quadrupole antennae can further considerably enhance the single transit absorption. (orig.)