We study a smoothing effect of a non-linear degenerate parabolic probl
em, the Vlasov-Poisson-Fokker-Planck system, in three dimensions. We p
rove that a solution gives rise actually to very smooth macroscopic de
nsity and force field for positive time. This is obtained by analyzing
the effect of the Fokker-Planck kernel on the force term in the Vlaso
v equation and using classical convolution inequalities. (C) 1995 Acad
emic Press, Inc.