A damping mechanism for collective oscillations in plasmas. If the velocity of the wave associated with the collective oscillation is comparable to the velocities of individual electrons in plasmas, with the velocities of the electrons being determined by their thermal motion, there is a transfer of energy from the wave motion to the electrons. This causes damping (attenuation) and eventually destruction of the wave motion. The process is named after the Soviet physicist Lev Davidovich Landau, who postulated this type of damping in 1946. A similar mechanism occurs for the damping of collective excitations in the quantum theory of many-body systems by energy transfer to individual quasiparticles.