  We investigated the electrostatic interaction between two identical dust
grains of an infinite mass immersed in homogeneous plasma by employing
first-principles N-body simulations combined with the Ewald method. We
specifically tested the possibility of an attractive force due to overlapping
Debye spheres (ODSs), as was suggested by Resendes et al. (1998). Our
simulation results demonstrate that the electrostatic interaction is repulsive
and even stronger than the standard Yukawa potential. We showed that the
measured electric field acting on the grain is highly consistent with a model
electrostatic potential around a single isolated grain that takes into account
a correction due to the orbital motion limited theory. Our result is
qualitatively consistent with the counterargument suggested by Markes and
Williams (2000), indicating the absence of the ODS attractive force.
