Numerical diffusion is introduced by any numerical scheme as soon as small
scales fluctuations, generated during the dynamical evolution of a
collisionless plasma, become comparable to the grid size. Here we investigate
the role of numerical dissipation in collisionless plasma simulations by
studying the non linear regime of the two stream instability. We show that the
long time evolution of the Vlasov - Poisson system can be affected by the used
algorithm.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France