EVOLUTION OF THE POTENTIAL IN COSMOLOGICAL GRAVITATIONAL CLUSTERING

The gravitational potential is constant to linear order in cosmologica l gravitational clustering. In this paper we present results of testin g the conjecture, proposed by Pauls & Melott, that the effect of nonli near evolution on the potential can be better described by smoothing i t on the scale of nonlinearity. We show two-dimensional simulations co nsisting of an N-body code in which particles are accelerated not by t heir mutual attraction, but by the gradient of the initial potential s moothed on the current scale of nonlinearity. This approximation produ ces results considerably improved over using a constant potential to m ove particles, and it is generally better than any scheme we have test ed, lending further support to the smoothing description of the evolve d potential.