We present molecular dynamics simulations of driven vortices in layered
superconductors in the presence of an external homogeneous force and point
disorder. 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
considered and the Josephson interlayer coupling is neglected. We numerically
evaluate the long-range magnetic interaction between pancake vortices exactly.
We analyze the vortex correlation along the field direction on (c-axis). We
find that above the critical current, in the ``plastic flow'' regime, pancakes
are completely uncorrelated in the c-direction. When increasing the current,
there is an onset of correlation along the c-axis at the transition from
plastic flow to a moving smectic phase. This transition coincides with the peak
in the differential resistance.Comment: 4 pages, 3 figures, needs espcrc2.sty. Submitted to the proceedings
of the M2S-HTSC-IV Conferenc