Landau damping of an electron plasma wave in a plasma with modulated density

The collisionless Landau damping is analyzed for a homogeneous plasma with a sinusoidal density perturbation. The exact damping values are obtained by numerically solving the kinetic dispersion relation of the electron plasma mode. Quantitative results are provided on the influence of the amplitude and the wave vector of the density modulation. Within a simplified fluid framework, a fit is given to these data.