Two body interactions between charged grains in a dusty plasma

摘要

Under the assumption of invariant surface potential, the interaction potential between two charged grains immersed in a plasma has been obtained. Based on the potential, the coagulation cross-section of two grains is deduced. The results indicate that the changes in grain charge with the intergrain distance benefit the coagulation process. The interaction between two dressed grains is studied and a modified Debye potential is obtained by taking the cross terms of shield effects into account. A potential well is found at the intergrain distance r = (1 + 3~(1/2)) #lambda#_D on the potential. The creterion of grain trapping in the well leads a molecule formation or solidification condition #GAMMA# > 115.