Study Of Mechanics Of Dust Plasma With Numerical Simulation

Dust plasma is the ionized gas containing colloid nano/microscopic particles (dust). Generally, the dust plasma, composing of electrons, ions and charged dust particles exist in both the space and the laboratory. In the present paper, two main aspects: the dust elimination in plasma application and dust crystals in basic colloid physics have been discussed with simulation method.Firstly, a new method to eliminate dust particles wa"s designed. For a cylindrical plasma discharge chamber, a devise to eliminate the dust with the aid of the E×B drag force was schemed out and validated with a three fluid model.Then, the one dimensional and two dimensional sheath characteristics have been studied. In the dust crystal experiments, the dust particles are normally confined in a two dimensional sheath of a concave electrode. The sheath characteristics affect and determine the dust particles' characteristics and there motions, which makes it necessary to obtain the sheath characteristics to study the dust particles. So a two fluid model has been preformed" to study the one dimensional and two dimensional sheaths, which provides the basal information for the later works.A molecular dynamics equation of dust particles has been presented to study the dust crystals. Considering that there are few dust particles so that the dust particles do not influence the sheath formation, a bold dust molecular dynamics model has been established, in which the gravities of dust particles, dust charging, ion drag force and wake wield have been included. Through the model, different crystalline structures of dust particles have been simulated and discussed.At last, formation of dust void has been simulated and discussed. A numerical dust void experiment has been preformed comparing to the experiment of [R. P. Dahiya et al., Phys. Rev. Lett. 89, 125001 (2002)]. The results of the two experiments agree extremely well. Then from the simulation, It is found that the formation of the dust void in the axisymmetric three dimensional sheath is due to a gentle potential bump in the central region of the electrode caused by the cylindrical geometry.