  The thermal motion of a dust particle levitated in a plasma chamber is
similar to that described by Brownian motion in many ways. The primary
differences between a dust particle in a plasma system and a free Brownian
particle is that in addition to the random collisions between the dust particle
and the neutral gas atoms, there are electric field fluctuations, dust charge
fluctuations, and correlated motions from the unwanted continuous signals
originating within the plasma system itself. This last contribution does not
include random motion and is therefore separable from the random motion in a
normal temperature measurement. In this paper, we discuss how to separate
random and coherent motion of a dust particle confined in a glass box in a
Gaseous Electronic Conference radio frequency reference cell employing
experimentally determined dust particle fluctuation data analyzed using the
mean square displacement technique.
