Kinetic theory of dusty plasmas. III. Dust-dust collision integrals

The dust-dust collision integrals found in the kinetic theory of dusty plasmas [Tsytovich and de Angelis, Phys. Plasmas 6, 1093 (1999); 7, 554 (2000)] are analyzed. Analytic expressions are derived and numerical results are given for the case of thermal distributions to assess their importance and dependence on dusty plasma parameters. Modifications of Debye screening by collective dust effects are obtained. A study of the forces between two test dust particles is presented and the appearance of weakly screened attraction forces at distances larger than the Debye screening length is analyzed. These forces are related to the collective shadow effect in dust charging and operate at distances larger than the previously known noncollective shadow attraction forces. The dependence of the collective attraction forces on dust temperature is analyzed. (C) 2001 American Institute of Physics.