  In this paper we have studied the influence of reversed shear on the
improvement of the confinement's quality in the plasma of tokamak and
especially in reducing the anomalous transport. For that, we have used a
special model for the drift wave fields. Comparison between particles
trajectories for normal and reversed shear is carried out in 2 D and 3 D
presentation. Also, the diffusion coefficient of particles for the two cases,
normal and negative shear, is evaluated.
