Particle simulations of high-intensity laser interaction with cone targets

Abstract

Hollow cone-shaped overdense plasma targets were used to investigate the generation and transport of fast particles in a high-intensity laser-matter interaction. Using 2d PIC simulations we examine cone, cone-wire and cone with an open tip target designs. Localization of electron jets and an angular spread are found in all cases of the laser-cone interaction. However, in the cone-wire geometry, at later times, the charge separation and radial electric fields around the wire collimate electron streams with an electron hot spot at the front end of the wire. The main mechanism of the electron transport in the targets is the reflection of electrons from the potential walls of the cone surface, and no significant surface electron transport is observed. Furthermore, the presence of harmonics in the reflected light suggests that the field intensity in the cone can be enhanced not only by simple multiple reflection but also by the field modulation due to harmonics generation. Moreover, it is found that the laser interaction with the open-tip cone can efficiently generate trains of short (<λ) attosecond electron sheets close to the laser axis.