Potential of a Dust Grain in a Nitrogen Plasma with a Condensed Disperse Phase at Room and Cryogenic Temperatures

The first numerical study is presented of the self-consistent potential of a dust grain in a nitrogen plasma with a condensed disperse phase at room and cryogenic temperatures and at high gas pressures for which the electron and ion transport in the plasma can be described in the hydrodynamic approximation. It is shown that the potential of the dust grain is described with good accuracy by the Debye potential, in which case, however, the screening radius turns out to be larger than the electron Debye radius. The difference between the radii is especially large in a plasma with high ionization rates (about 10[sup 16]–10 [sup 18]cm[sup –3]s[sup –1]) at room temperature. It is found that, in a certain range of the parameters of a nitrogen dusty plasma, the parameter describing the interaction between the grains exceeds the critical value above which one would expect the formation of plasma–dust structures such as Coulomb crystals. For a plasma at cryogenic temperature (T = 77 K), this range is significantly wider.