Power Transfer and Current Generation of Fast Ions with Large-k(sub theta) Wavesin Tokamak Plasmas

摘要

Transfer of energy and momentum between fast ions and electrostatic wavespropagating in one preferential poloidal direction in tokamaks is investigated. The results indicate that net power transfer from the ions to the spatially localized wave by the free expansion of ions sustained by an isotropic steady ion source is not possible unless there are special absorbing boundaries on the low energy side or reflecting boundaries on the high energy side of the ion diffusion paths for a well localized wave structure. In the absence of such boundaries, only reduction of Landau damping is obtained in comparison to values found in an infinite homogeneous system. Irrespective of the direction of power transfer, i.e., wave damping or amplification, momentum generation in toroidal systems follows from the toroidal momentum conservation when the ions experience radial diffusion by the wave. Quantitative results are obtained by deriving collision and ion-wave interaction operators for Monte Carlo simulations in slab and toroidal systems.