Fluid and kinetic (Vlasov) numerical simulations of the wave-plasma interaction in conditions of relevance for RF heating

The interaction of electrostatic waves of finite amplitude with the plasma which characterizes the edge region of a magnetic confinement device during radiofrequency (rf) heating experiments is investigated on the basis of fluid and kinetic models. In the former case, the time evolution of a two-dimensional initial distribution of the rf energy, coupled with the slow plasma density motion through the action of ponderomotive forces, is investigated. A fluid magnetized plasma is considered and the electric field evolution is treated in the frame of the slowly varying envelope approximation. In the latter case, the Vlasov equations for electrons and ions are integrated together with the Poisson equation in a one-dimensional geometry. An externally applied a.c. forcing term acts on both the species with given frequency and wavevector spectrum, which can be either monochromatic or broad. It is shown that, under conditions typical of the lower hybrid or ion Bernstein heating experiments of tokamak plasmas, numerous nonlinear effects are expected to accompany the wave-plasma interaction, as for example, the formation of strong plasma non-uniformities, the acceleration of charged particles, the nonlinear plasma heating.