Landau damping
In physics, Landau damping is a mechanism by which oscillations in a charged medium (typically a plasma) are damped by non-collisional interactions with said medium. It is named after its discoverer, Soviet physicist Lev Davidovich Landau (1908–68). As the oscillation moves through the medium with phase velocity it will accelerate slightly slower particles and decelerate slightly faster particles; if the former outnumber the latter (such as if the oscillation is travelling faster than the modal velocity of a Maxwell–Boltzmann distribution) the oscillation will lose its energy to drag and thus be damped. This phenomenon prevents an instability from developing, and creates a region of stability in the parameter space. It was later argued by Donald Lynden-Bell that a similar phenomenon was occurring in galactic dynamics, where the gas of electrons interacting by electrostatic forces is replaced by a "gas of stars" interacting by gravitational forces. Landau damping can be manipulated exactly in numerical simulations such as particle-in-cell simulation. It was proved to exist experimentally by Malmberg and Wharton in 1964, almost two decades after its prediction by Landau in 1946.
