Multi-fluid MHD model and calculations of Alfvén wave spectrum and dissipation in tokamaks

The numerical method is developed for calculations of wave excitation and dissipation in Alfven and in Ion Cyclotron Range of Frequency (ICRF) in axisymmetric tokamaks. Multi-fluid magneto-hydrodynamic plasma model is used and two-dimensional inhomogeneity of plasma parameters with arbitrary cross section of magnetic surfaces is considered. The difference scheme for the wave equation is not connected to magnetic field geometry and is suitable for the method extensions to nonlinear and three-dimensional case. Special care is taken to avoid the spectrum distortion and pollution. Relevant benchmark cases are presented. Finally, the results of numerical calculations of Alfven wave absorption are presented for the experimental conditions foreseen for the Tokamak Chauffage Alfven wave experiment in Brazil (TCABR) [Nucl. Fusion 30 (1996) 503]. In particular, the effect of toroidal mode coupling on the power deposition of Global Alfven Wave (GAW) eigenmodes is demonstrated.