Spontaneous formation of magnetic dipoles by interaction of intense laser with overdense plasma

When a laser radiation is incident on an overdense plasma it is unable to penetrate inside it. Nevertheless, a part of its energy gets transferred to the electrons. The dynamics of these energetic electrons inside the plasma is often a field of great interest. It has often been conjectured that the dynamics of the electrons in the plasma can be suitably described by the Electron Magnetohydrodynamic (EMHD) prescription. It is demonstrated here using PIC (Particle - In - Cell) simulation studies with the help of Osiris4.0 framework that this is indeed true. In 2-D simulations we observe a spontaneous formation of a variety of coherent solutions which essentially follow the dynamics of EMHD and its generalized fluid descriptions. We discuss the conditions for the formation of such structures and also identify their particulate kinetic behaviour in this study.