DUSTY PLASMAS IN THE VICINITY OF A LARGE DIELECTRIC OBJECT IN SPACE

The mutual interaction of plasma and dust is an important feature of the extraterrestrial environment. We investigate modifications of this interaction in the presence of a large material body. In our study we assume the dust density to be low, with a random, Maxwellian velocity distribution and a dynamically determined dust density distribution. We have also assumed spherical symmetry to simplify the problem and find that the magnitudes of both the charge on the body and its potential are reduced by the presence of dust. We also find a significant reduction of the dust density near the body due to electrostatic repulsion. Both the reduced magnitude of charge on the body and the repulsion of dust are sensitive to the mean dust velocity; more slowly moving dust is more effectively repelled and also results in a greater magnitude of charge on the body. In addition, some effects depend strongly on the size of the body with respect to the Debye length. The dust density as a function of radial distance from the body approaches its asymptotic value most slowly when the size of the body is of the order of 1-10 Debye lengths.