Static behavior of fine particle clouds in fine particle (dusty) plasmas under gravity

Static behavior of fine particle cloud in fine particle (dusty) plasmas under gravity is analyzed numerically on the basis of the drift-diffusion equations. The system is assumed to have one-dimensional structure and the effect of the ion drag force is taken into account. The results confirm the analytically obtained prediction that we have an enhanced charge neutrality in fine particle clouds under gravity as well as under microgravity. They are also compared with a simple model based on the enhanced charge neutrality in clouds to show its applicability.