Large Amplitude Oscillations Sustained by Stochastic Plasma Density Fluctuations in Plasma Sheaths

We have examined the dynamics of a dust grain immersed in a plasma sheath. It is shown that the presence of stochastic plasma density variations can sustain a large amplitude dust grain oscillations once these have been induced by a slow plasma number density variation. Such dust oscillations have been observed in the sheath region of an radio-frequency or a dc plasma discharge at very low pressures. A physical mechanism for the excitation and maintenance of large amplitude grain oscillations is discussed.