We present molecular dynamics simulations of driven vortices in layered sup
erconductors in the presence of an external homogeneous force and point dis
order. We use a model introduced by J.R.Clem for describing 3D vortex lines
as stacks of 2D pancake Vortices where only magnetic interactions are cons
idered and the Josephson interlayer coupling is neglected. We numerically e
valuate the long-range magnetic interaction between pancake vortices exactl
y. We analyze the vortex correlation along the field direction on (c-axis).
We find that above the critical current, in the "plastic flow" regime, pan
cakes are completely uncorrelated in the c-direction. When increasing the c
urrent, there is an onset of correlation along the c-axis at the transition
from plastic flow to a moving smectic phase. This transition coincides wit
h the peak in the differential resistance.