  In this paper, I test by numerical simulations the results of Del Popolo &
Gambera (1998),dealing with the extension of Chandrasekhar and von Neumann's
analysis of the statistics of the gravitational field to systems in which
particles (e.g., stars, galaxies) are inhomogeneously distributed. The paper is
an extension of that of Ahmad & Cohen (1974), in which the authors tested some
results of the stochastic theory of dynamical friction developed by
Chandrasekhar & von Neumann (1943) in the case of homogeneous gravitational
systems. It is also a continuation of the work developed in Del Popolo
(1996a,b), which extended the results of Ahmad & Cohen (1973), (dealing with
the study of the probability distribution of the stochastic force in
homogeneous gravitational systems) to inhomogeneous gravitational systems.
Similarly to what was done by Ahmad & Cohen (1974) in the case of homogeneous
systems, I test, by means of the evolution of an inhomogeneous system of
particles, that the theoretical rate of force fluctuation d F/dt describes
correctly the experimental one, I find that the stochastic force distribution
obtained for the evolved system is in good agreement with the Del Popolo &
Gambera (1998) theory. Moreover, in an inhomogeneous background the friction
force is actually enhanced relative to the homogeneous case.
