Effect of density profile on beam control of intense laser-generated fast electrons

Abstract

Divergent relativistic electrons are produced during the intense laser interacting with overdense or solid targets. When these energetic electrons propagate through a structured two-layer target, a strong interface magnetic field will be generated due to the plasma density difference near the interface. This field will affect the motions of the electrons and can be utilized to control the beam divergence. In this paper, the effect of the target density profile on beam control is explored via a physical model as well as two-dimensional particle-in-cell simulations. It is shown that the fast electron number and forward current can be greatly concentrated and enhanced if the plasma density of the inner layer is suitably lower than that of the outer layer.