Propagation properties of density pulses and ion acoustic waves in collisionless plasmas calculated from the linearized Vlasov equation

Calculations of the propagation properties of ion density perturbations and waves through collisionless plasmas with Maxwellian velocity distribution functions are presented. The calculations are based on the linearized Vlasov equation, which is solved with the perturbation as a boundary value. Solutions are presented for various values of the ratio between electron and ion temperature and for various drift velocities of the background plasma and of the perturbations at the boundary. Some of the results are compared with those obtained in a simple Landau treatment of the problem.