The weak collision effect on bounce-resonance dissipation in magnetized toroidal plasmas

The asymptotic solution of the Vlasov equation under the drift approximation with a simplified Fokker-Planck collision operator (Boltzmann equation) is presented for an axially symmetric toroidal plasma configuration with a circular cross section of magnetic surfaces. Analytical expressions for the parallel component of the dielectric permittivity tensor are obtained. These expressions are used for theoretical analyses of the collision effect on the bounce-resonance wave dissipation. Conditions of a collisionless description of radio-frequency (rf) oscillations are found. The evaluated dielectric tensor components can be used for computer calculations of the rf field structure and the collisionless dissipated power related to trapped and untrapped electrons in tokamak plasmas. (author)