  When a laser field is incident on an overdense plasma it is unable to
penetrate inside it. Nevertheless, a part of its energy gets transferred to the
electrons through a variety of mechanisms (e.g. vacuum and $\vec{J}\times
\vec{B}) heating [1, 2]). The dynamics of these energetic electrons inside the
plasma is a field of great interest. It is demonstrated here using 2-D PIC
(Particle-In-Cell) simulation that when a high intensity laser pulse is
incident on an overdense target, energetic electrons get generated which
spontaneously organize themselves to form coherent structures. These coherent
structures are observed to have similar dynamical traits as displayed by the
solutions of the EMHD (Electron Magnetohydrodynamic) model [3]. This is
noteworthy that EMHD is an approximate model and is applicable for the dynamics
of non-relativistic electrons. However, in these simulations, the electron
energy is in the relativistic regime as the laser intensity is significantly
high. Thus, it shows that the relativistic dynamics also permits the existence
of robust coherent structures. Interesting kinetic behaviour at particle level
is observed in the simulation which shows that the coherent structures take
background electrons in its fold and subsequently emit them at a higher energy.
