ANALYSIS OF FAST MINORITY ION DISTRIBUTION AND CURRENT GENERATION FORICRF AND LH HEATING

Dynamics of fast minority ions energized by ion cyclotron resonance an d lower hybrid heating in tokamaks is investigated by cylindrical 2D F okker-Planck and toroidal 3D Monte Carlo calculations. The power excha nge between the waves and minority ions, the ensuing fast ion bootstra p current and the power deposition are calculated in the presence of f ast ion radial diffusion and thermal minority ion source near the plas ma edge. Both lower hybrid and ion cyclotron heating are observed to i ncrease by increasing overlapping of the heating regimes and by radial diffusion, because of the enhanced diffusion of the ion cyclotron hea ted ions from their resonance region to the peripheral lower hybrid wa ve region, and diffusion of thermal ions from the plasma edge to the i on cyclotron heating region. The fast minority ion current is found to be strongly modified by the bootstrap current generation in the cyclo tron heating region. An analytical expression to describe the RF-induc ed bootstrap current is presented.