Steady State of the Dusty Plasma in a dc Discharge

The steady state formed by the diffusion of plasma particles in an inhomogeneous dusty plasma is investigated theoretically and compared with our previous experimental results Nucl. Fusion Plasma Phys. 20(2000)180 (in Chinese); Phys. Plasmas 8(2001)1459. The negatively charged dust grains with average charge number of the order of 10⁵ on a single grain enhance the plasma inhomogeneity by decreasing the diffusion velocity, and can cause significant depletion of electrons. The theoretical electron density profile is in good agreement with the experiment, and the theoretical profile of the electron-to-ion density ratio is in reasonable agreement with experimentally estimated data.