Ambipolar diffusion in an inhomogeneous dusty plasma

The ambipolar diffusion of plasma particles in a column of inhomogeneous plasma containing dust grains is investigated analytically as well as numerically. The grains act as charge sinks and behave like an immobile but charge-varying negative background. They can lead to significant depletion of the electron density and decrease the diffusion scale length. The theoretically obtained election density distribution agrees well with that from experiment.